FR2775537A1 - Wide temperature range thermistor especially useful as a temperature sensor for automobile exhaust gas - Google Patents

Abstract

A sintered thermistor body is produced by sintering a powder obtained from a liquid precursor metal compound mixture. An Independent claim is also included for a temperature sensor comprising a thermistor produced by the above process, the grain size of the sintered body being less than 1 mu .

Description

N of European publication: N of application N and date of

  European Patent Bulletin in which the grant was issued:

  THERMISTOR DEVICE, METHOD FOR MANUFACTURING

  THERMISTORIES AND TEMPERATURE SENSOR

BACKGROUND OF THE INVENTION

  FIELD OF THE INVENTION The present invention relates to a thermistor device which can detect temperatures in the range from room temperature to

  high temperature of approximately 1000 C, i.e.

  a wide range thermistor device, as well as a method of manufacturing such a thermistor device, and which is particularly well suited for use in a temperature sensor for

  automobile exhaust.

2. Description of the prior art

  Thermistor devices for temperature sensors are used for measuring temperatures in the range of 400 to 1300 C, ie medium temperature at high temperatures, for the measurement of exhaust gas temperatures. automobiles, gas flame temperatures in gas-fired boilers and the like, and

heated ovens.

  The resistance value and the resistance-temperature coefficient (temperature dependence of the resistance value) indicate the characteristics of this type of thermistor device. Here, so that the temperature sensing circuits which constitute a temperature sensor correspond to a range of practical resistance value, the resistance value of the thermistor device is preferably within a stipulated range. For this reason, perovskite and equivalent materials are mainly used as materials which have adequate strength value characteristics for a

wide range thermistor.

  Examples of proposed thermistor devices that use perovskite-type materials are provided in Japanese patent applications.

  published unexamined JP-A-6-325 907 and JP-A-7-201 528.

  In order to achieve a thermistor device that is usable over a wide temperature range, oxides of Y, Sr, Cr, Fe, Ti and other elements are mixed in a stipulated composition ratio, ground, granulated and fired to obtain a thermistor device that is a perfect solid solution to

  medium of the solid phase method.

  The resistance value and the resistance-temperature coefficients represent the characteristics

  resistance value of a thermistor device.

  Considering the resistance value range of the temperature sensing circuit in a normal temperature sensor, the resistance value of the thermistor device must be 50Ω to kΩ in the operating temperature range. In addition, if a thermistor device is subject to heating from room temperature to 1000 C or equivalent, it is preferable that the change between the initial resistance value and the resistance value.

  after heating is as small as possible.

  Each of the unexamined Japanese patent applications mentioned above (Kokai) proposes thermistor devices consisting of various perfect solid solutions, but only the data concerning thermistor resistance values at 300 C or higher are described. For this reason, the present inventors have sought the resistance value characteristics of the various thermistor devices in the various unexamined Japanese patent publications (Kokai) to

  temperatures close to the ambient temperature.

  As a result, these thermistor devices which exhibit characteristics of stable resistance values in heating from room temperature to 1000 C or equivalent, have shown a high resistance value in the region of room temperature at 300 ° C. , being indistinguishable from a resistor, so the temperature could not be detected. On the other hand, these thermistor devices that meet the low resistance value requirement of 50 D at 100 kn showed a change in resistance value in the heater which varied by 10% or more over the initial resistance value, so that they

lacked stability.

  In any case, there was no thermistor device (a "wide range" thermistor device) that satisfies both conflicting resistance characteristics, low resistance value characteristics in the temperature range. ambient at 1000 C and stability of the

  low resistance value in a heating.

  In view of the problems mentioned above, the first object of the present invention is to provide a thermistor device which has stable characteristics and which shows a small change in its resistance value even in heating from room temperature to room temperature. at 1000 C or equivalent, and which also has a resistance value of 50 n to 100 kΩ in the range of

  temperatures from room temperature to 1000 C.

  On the other hand, in recent temperature sensors for automotive exhaust (exhaust temperature sensors), there is a strong demand to incorporate these exhaust temperature sensors into systems for detecting the exhaust temperature. Exhaust gas temperature before and after the catalyst to detect the deterioration of the catalyst used for the change of exhaust gases from non-toxic gasoline vehicles, and in systems for detecting the exhaust temperature before and after the catalyst to control the catalyst temperature to clean the exhaust gas, particularly NOx at

from diesel vehicles.

  However, temperature sensors that use conventional thermistor devices have a large amount of dispersion in their

  resistance-temperature characteristics (characteristics

  R-T ticks), for example, their temperature accuracy is 20 to 30 C (from room temperature to 600 C), which is not sufficient for the control of high precision systems. Thus, in order to be incorporated in such systems, the development of thermistor devices that can achieve such high temperature accuracy is desirable. To this end, the present inventors have conducted background studies of the structure, methods of manufacture and other aspects of conventional thermistor devices, and have encountered the following problems with

  increasing the temperature accuracy.

  Namely, in the solid-phase method mentioned above, the mixing and grinding of a plurality of oxide materials is carried out by means of a ball mill or the like, but because of inadequate grinding capacity, the average grain size of the thermistor materials after grinding has a limit of 1-2 μm, so that uniform mixing is not achieved. In addition, because of this difference in the average grain size of the oxide materials, the reactions are not uniformly conducted in the calcination, sintering, and other temperature treatments, so that the composition of the raw materials of the thermistor produced by the reactions

thermal becomes non-uniform.

  Moreover, in the mixing and grinding operations mentioned above carried out by a ball mill or the like, the constitutive elements of the aluminum balls or the equivalent of the grinding media mix with the thermistor material as impurities, causing Thus, a dispersion of resistance or a divergence from the desired composition of the thermistor device Therefore, the dispersion of the resistance value of the obtained thermistor device becomes significant and a temperature sensor that uses this thermistor device will have a dispersion in its characteristic RT, bringing

  degradation in temperature accuracy.

  In the current state, the systems mentioned in

  above can not be achieved with the temperature accuracy of temperature sensors that use conventional thermistor devices, so that thermocouples or platinum (or equivalent) resistors with high accuracy but high cost,

  are used as temperature sensors instead.

  However, in each case, there is no temperature sensor that uses thermistor devices that has a temperature accuracy

  (for example, 5 C over the ambient temperature range -

  600 C) of a level that can be applied to the system

  mentioned above and equivalent.

  To this end, in view of the problems mentioned

  above, the second object of the present invention is to provide a method of manufacturing a thermistor device from a sintered body so that the dispersion of the resistance value of the

thermistor be reduced.

  On the other hand, when the thermistor device mentioned above is used in a temperature sensor that detects the exhaust gas temperature of an automobile, the thermistor devices located at the detector sensor tip Temperature sensors are typically covered with a metal cover to prevent the accumulation of debris, soot or the like from the controlled gas. Here, since the metal cover is subject to thermal oxidation due to the heating of the hot exhaust gas to generally 900 C, the inside of the metal cover is a reducing environment, and so the thermistor device inside is subject to a reduction action and its resistance value may change, causing problems. For this reason, the temperature sensors are typically placed in electric furnaces and subject to thermal aging treatment at 900-1000 C for 100 hours. However, while the temperature sensor is in use, if air enters the lid due to a hole in the lid or the lid has losses, there is a risk that the thermistor device itself be again subject to a

  reducing environment and the change mentioned in

  in it will occur.

  In JP-A-9-69417, even if special metallic materials, for example, Inconel 600TM or other materials, are selected for the metal cover and machining is performed, the problem of changing the value resistance is still not solved in the case where the thermistor device itself is subject to a reducing environment. In any case, it is not possible to propose a thermistor device which exhibits a resistance value stability when the thermistor device itself, in a temperature sensor or

  equivalent, is subject to a reducing environment.

  In light of the above-mentioned problems, the third object of the present invention is to provide a device structure that has a resistance value stability even in the case where the thermistor device is subject to a reducing environment.

SUMMARY OF THE INVENTION

  Conventional thermistor devices are perfect solid solutions having a perovskite-like structure, but the present inventors have considered that obtaining resistance characteristics that tend to conflict as described above would be

  difficult with a perfect solution of a single compound.

  For this purpose, the inventors intended to make the first object mentioned above by using a new thermistor material consisting of a mixed sintered body formed by mixing two types of compounds: a perovskite-like material (oxide) which comprises a relatively low resistance value and a material that has a resistance value

relatively high.

  As a result of these studies of various perovskite-type materials, the inventors have experimentally discovered that the materials which comprise the

J 2775537

  characteristics of resistance suitable for making the object mentioned above, should preferably have the composition (MlM2) O3 (where M1 is at least one or more elements selected from the elements of Group 2A or Group 3A of the Periodic Table of Elements , except for La, and o M2 is at least one or more elements selected from the elements of Group 2B, Group 3B, Group 4A, Group 5A, Group 6A,

  Group 7A or Group 8 of the Periodic Table).

  Here, La is highly hygroscopic and reacts with moisture in the atmosphere to produce unstable hydroxides that could create damage to the thermistor device, so it is not

used as Ml.

  On the other hand, it appears from the study that A1203 (aluminum oxide), which has a relatively high resistance value, and stabilizes the resistance value of the thermistor, has been experimentally found to be the complementary material the

more interesting in the mix.

  Therefore, the first aspect of the present invention is a thermistor device made of a mixed sintered body of (MlM2) O3. A1203 obtained by sintering

  a mixture of (MlM2) O3 and Al203 mentioned above.

  When this thermistor device is incorporated into a temperature sensor and the resistance value characteristics of the device have been checked, the change in the resistance value even on a thermal evolution from room temperature up to 1000 C was small at a few% and stable, and the resistance value was confirmed from 50 f to 100 kQ in the temperature range

  from room temperature up to 1000 C.

  Therefore, with this thermistor device, it is possible to provide a "wide range" thermistor device, which is capable of detecting temperatures over the wide temperature range from room temperature to 1000 C, and which has stable characteristics, in that its change in the resistance value is small on the evolution of heating from room temperature to

1000 C or equivalent.

  In addition, from the studies performed by the present inventors, such as the various elements in the pervoskite compound mentioned above (M1M2) O3, M1 should preferably be one or more elements selected from the group Y, Ce, Pr , Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, Mg, Ca, Sr, Ba and Sc, while M2 should preferably be one or more elements selected from the group Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Ga, Zr, Nb, Mo, Hf, Ta and W. Moreover, it results from these studies on the mixing ratio of (M1M2) O3 and Al2O3, that it has been found that as long as the mixing ratio is within a stipulated range, that is, when considering the molar fraction of (MlM2) O3 mentioned above

  as a and the fraction of A1203 mentioned above

  above as b, as long as the relation among these mole fractions a and b are 0.05 <a <1.0, O <b <0.95 and a + b = 1, then the effects mentioned above thermistor device can be realized from

more reliable way.

  In this way, these mole fractions a and b can be varied over a wide range, so the

  resistance value and resistance coefficients

  temperature can be controlled over a wide range by mixing and calcining appropriately the two

elements (MM2) O3 and A1203.

  In addition, it has been experimentally determined that in the mixed sintered body mentioned above (M1M2) O3.A1203, Y203 (yttrium oxide) can be included with A1203 instead of A1203 alone, as

complement to (MlM2) O3.

  Based on this knowledge, a thermistor device made of a mixed sintered body of (MlM2) O3.Y203.A1203 is provided. This thermistor device can have the same effects as the thermistor device mentioned above made of (MlM2) O3.A1203. Moreover, it has been found that as long as the mole fraction of (MnM 2) O 3 and the total mole fraction b of Y 2 O 3 and Al 2 O 3, satisfy the relationships 0.05 a <1.0 0 <0.95 and a + b = 1, then the effects mentioned above the device of

  thermistor can be obtained more reliably.

  In a sintered body, a sintering aid is added in order to improve the sintering characteristics of the granules, and experimental studies on various sintering aids have shown that it has been found that the use of a sintering aid consisting of SiO2 and at least one member selected from CaO, CaCO3 and CaSiO3, is preferable for all of the above sintered blend bodies. By this means, a wide range thermistor device with higher sintering density and other

  higher characteristics, is obtained.

  As the experiments unfolded, it was found that temperature sensors that used thermistor devices made of the mixed sintered body mentioned above (MlM2) O3. A1203 or mixed sintered body mentioned above (MlM2) O3.Y203. A1203 (hereinafter, the two mixed sintered bodies taken together are referred to as "mixed sintered bodies A") have shown that a dispersion in the accuracy of the temperatures detected among the sensors manufactured on the levels of 20-30 C over the range of temperatures starting from the ambient temperature and

up to 1000 C.

  Here, this mixed sintered body A is normally obtained by calcining the oxides of M1 and M2 to obtain (M1M2) O3 (the first preparation step) which is

  then mixed with A1203, or Y203 and A1203 (hereinafter

  after abbreviated as "A1203, etc."), then molded and sintered

  (the second stage of preparation).

  It should be noted that in the case where Y is included in M1 in the mixed sintered body A of (M1M2) 03.Y203.A1203, an excess of Y203 can be added in advance as the ingredient of M1 in the first preparation step to obtain (MlM2) 03.Y203 in place of (M1M2) 03. In this case, an appropriate amount of Al 2 O 3 is mixed with (M 1 M 2) O 3 .Y 2 O 3 obtained during calcination to provide a mixed sintered body A which ultimately has the desired composition ratio. Here, from the point of view of the further increase in temperature accuracy (reducing the dispersion in the detected temperature accuracy among the sensors), investigations were made under various conditions in the steps of making thermistor devices such as the formulation, molding,

  heating (cooking) and other conditions.

  As a result, it has been found that the aforementioned dispersion in the temperature accuracy increases when the average grain size of (M1M2) 03 or (M1M2) 03.Y203 obtained by calcination (hereinafter referred to as " calcine A "when taken together) is larger than the average grain size of Al 2 O 3, etc., so that the two do not mix uniformly and there is a dispersion in the composition of the mixed sintered body A , finally increasing the dispersion in the resistance of the thermistor device. Therefore, studies have been made from the point of view that the average grain size of calcine A can be made to be the same as the average grain size of Al 2 O 3 in the mixed state prior to sintering, and then a mixture uniform of the composition was realized. As a result, it has been determined experimentally that when calcine A is mixed with Al 2 O 3, etc., and ground, and that the average grain size of this mixture is brought below the average grain size of the A1203 etc. before mixing, this is enough. Namely, using a manufacturing method that includes this type of grinding (the first method of manufacture), a uniform mixture of calcine A with A1203, etc. is carried out by fine grain milling, and thus the fluctuations in the composition of the mixed sintered body A are reduced so that the dispersion in the resistance value of the thermistor device can be reduced. Therefore, a wide range thermistor device with better temperature accuracy (lower dispersion in temperature accuracy

  between sensors) can be provided.

  In addition, from the point of view of increasing the detected temperature accuracy of a temperature sensor that uses a thermistor device made from the mixed sintered body A, investigations have been conducted as to the methods of manufacturing devices. thermistor. As a result, it was found that the dispersion in the calcin A composition ultimately affected the dispersion in the composition of the mixed sintered body A (ie, the dispersion in the

  resistance value of the thermistor devices).

  Here, we present an example of a study of the cause of dispersion in the composition of calcine A itself, in the case where a calcine A of Y (Cr0.5Mn0.5) 03 is used, ie say in the case

  wherein M1 = Y and M2 = Cr, and Mn in (M1M2) O3.

  The preparation of Y (Cr0.5MnO5) O3 may for example be carried out as follows (see Figure 4). The material Ml Y203 (average grain size 1 μm) and the materials M2 Cr203 (average grain size 4% m) and Mn203 (average grain size 7 μm) are weighed to give a molar ratio of Y: Cr: Mn = 1: 0.5: 0.5, mixed and milled in a conventional ball mill or equivalent, and this mixture is calcined at 1000 C or higher, to obtain

Y (Cr 0.5Mn 0.5) 03.

  Here, the low limit of the average grain size after mixing and grinding that can be achieved with a ball mill or the like, is approximately 2 μm, and the average grain size of Cr 2 O 3 and Mn 2 O 3 is larger than the dimension.

average grain size of Y203.

  Therefore, because of the differences in the average grain size of the individual raw materials Y203, Cr203 and Mn203, the Y (Cro, 5MnO, 5) O3 obtained by the calcination reaction of the mixture of Y203 and Cr203 and Mn203 is a composition. which diverges from the ideal molecular ratio Y: Cr: Mn = 1: 0.5: 0.5, but it is a mixture of various compositions ranging from a composition of Y: Cr: Mn = 1: 0.6: 0 , 4 to a composition of

Y: Cr: Mn = 1: 0.4: 0.6.

  Each of these compositions in the range of a composition of Y: Cr: Mn = 1: 0.6: 0.4 to a composition of Y: Cr: Mn = 1: 0.4: 0.6 has a value of resistance and a different coefficient of resistance-temperature (value Δ), so that resistance varies from device to device, becoming the cause of

  dispersion in the device resistance values.

  Moreover, in the case where some of the starting materials of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 (the diverging portion of the ideal composition ratio) remain as unreacted materials, this will become the cause of dispersion.

  in the device resistance values.

  Here, it results from studies of mixing and grinding conditions in the first preparation step to obtain calcine A, that it has been experimentally determined that by mixing and grinding the M2 materials with the Ml materials in a blender of medium or equivalent, which has a greater milling capacity than that of a ball mill, if the average grain size of the mixture of the raw materials after mixing and grinding (the ground mixture) is brought below the dimension of grains

  medium of M1 material before mixing and also

  below 0.5 pun, then the difficulties mentioned above

  above can be suppressed, and better temperature accuracy than the practical level of 10 C can be achieved. Namely, a manufacturing method that includes this type of grinding (the second method of manufacture) is characterized in that during the mixing step in which the material M1 and the material M2 are mixed and ground, the material M2 is mixed and milled with the material M1, and this ground mixture is ground so that its average grain size is smaller than the average grain size of the materials M1 before mixing and also less than 0.5 μm, then the calcination is performed to obtain a calcine which is mixed with Al203, etc., molded

  in the prescribed form and sintered.

  Achieving a uniform grain size for materials M1 and M2 in this manner is intended to achieve a uniform mixture of the calcine composition to reduce dispersion in the calcine composition and suppress the presence of n unreacted raw material. Therefore, by combining the first method of manufacture with the second method of manufacture, the advantageous (meritorious) effects of the two methods of manufacture can be combined, and the dispersion in the resistance value of the thermistor device can be

reduced even more.

  As was stated in the description of

  In the above prior art, the present inventors have carried out studies of different steps in the manufacture of thermistor devices from the point of view of improving the temperature accuracy of temperature sensors that utilize thermistor devices. They discovered that the uniform mixture of raw materials is not obtained in the conventional solid phase method because of the large average grain size of the raw materials, and that there is non-uniformity of the composition after calcining , sintering and other temperature treatments. In addition, it results from other studies that in a thermistor device formed after the thermal reactions in the heat treatments mentioned above, the inventors have found that the dispersion in the composition of the crystalline phases, which predominantly dominates the value of resistance in particular ultimately affects the dispersion of the resistance value of the thermistor devices. In this connection, the case of the manufacture of a thermistor device from a mixed sintered body (mixed calcine) of 38Y (Cr 0.5MnO, 5) O 3 .62Y 2 O 3 using the phase method

  conventional solid will be described as an example.

  In 38Y (Cr0.5Mn0.5) 03.62Y203, Y203 (yttria, yttrium oxide) has characteristics close to those of an insulator, so that the crystalline phase which predominantly dominates the resistance value (domination phase of the resistance value) is the Y (Cr0.5Mn0.5) O3 which has a pervoskite structure. Thus, the dispersion in the composition of Y (CrO 5 MnO 5) O 3 is the problem. This 38Y (Cro0.5Mn0.5) O3.62Y203 may for example be prepared from

  the following way (see Figure 8).

  First, in the solid-phase method mentioned above, the Y203 oxide raw material (average grain size of approximately 1 lumen) and the other Cr203 raw materials (average grain size of approximately 4 μm) and Mn203 (average grain size of approximately 7 μm) are used as starting materials. Then, in the formulation step, Y203, Cr203 and Mn203 starting materials are weighed so that the final composition of the thermistor device can become 38Y (Cro0.5Mn0.5) O3.62Y203. Then the weighed materials are mixed and milled in a ball mill or equivalent, and the mixture of starting materials is subjected to calcination at 1000 C or higher, to obtain

  a calcine of 38Y (Cr0.5Mn0.5) 03.62Y203.

  Here, because of the difference in the grain size among Y203, Cr203 and Mn203 starting materials, limitations in the mixing and milling capacity of the ball mill or equivalent, Y (Cr 0.5Mn 0.5) which is the dominant phase of the resistance value in the calcine mentioned above, is a composition which diverges from the ideal ideal composition (Y: Cr: Mn = 1: 0.5: 0.5) and is a composition consisting of crystal grains of different compositions ranging from a composition of Y: Cr: Mn = 1: 0.6: 0.4 to one

composition of Y: Cr: Mn = 1: 0.4: 0.6.

  Each of these compositions in the range of a composition of Y: Cr: Mn = 1: 0.6: 0.4 to a composition of Y: Cr: Mn = 1: 0.4: 0.6 has a value of resistance and a coefficient of resistance-temperature (value P) different, so the resistance varies from one device to another. Moreover, in the case where some of the starting materials of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 (the diverging part of the ideal composition ratio) remain as unreacted materials, this would become the cause of dispersion in the resistance values of device. In addition, the dispersion in the resistance values of the devices due to the aforementioned dispersion in the composition occurs in Y (Cro, 5Mn0.5) O3 in calcine, so the same can be said in the case the composition of the thermistor device consisted of

  crystal of Y (Cro, 5Mno, 5) O3 or the equivalent alone.

  Here, the present inventors have thought that in order to reduce the dispersion in the calcine composition, the dispersion mentioned above in the composition, the presence of unreacted raw materials and other problems can be solved in the steps before calcination. In addition, the present inventors have focused on the use of the mixture of multiple raw materials that are not in the solid phase state for the metal oxides but rather in the liquid phase state of the precursor compounds which are easily dispersed or dissolved

in solvent.

  On the basis of this reflection, the result of the multiple experiments and studies concerning the 38Y (Cr0.5Mn0.5) O3.62Y203 mentioned above and, in addition, thermistor devices made of various sintered bodies, the present inventors have found that by using materials obtained by adjusting the composition of the precursor compounds in a liquid phase method to make a thermistor device, the composition of the crystal grains can be made uniform, the resistance value dispersion can be reduced and the temperature accuracy of the temperature sensor can be improved. That is, in the second aspect of the present invention, a plurality of precursor compounds that contain metal elements are mixed in the liquid phase to form a liquid mixture, and a metal salt precipitant (precipitant) is added to the liquid phase. liquid mixture to precipitate a

  gelatin containing a plurality of metallic elements.

  Then, by drying and heating this precipitation, the powdered raw material which is a powder composition containing a plurality of metal elements is formed, and then this powdered raw material is sintered to obtain a thermistor device as a

sintered body.

  Thus, since the plurality of precursor compounds disperse or dissolve in the liquid phase, they are unaffected by the average grain size as in the solid phase method, and may be mixed in the desired composition ratio in the state of fine grains of the molecular or atomic order, since the various precursor compounds can be mixed uniformly. As a result, the composition was finally obtained as a powder, i.e., the powdered raw material contains the metallic elements mixed with the desired composition ratio of the atomic or molecular order, so that the thermal reactions in the treatment water of

  subsequent heating are done in a uniform way.

  Therefore, finally, in a thermistor device manufactured as a sintered body, the dispersion in the composition of the crystal grains that constitute the thermistor device can be suppressed. In addition, temperature sensors that utilize thermistor devices manufactured using the manufacturing method of the present invention will have a smaller dispersion in the resistance value from one device to another, thus the temperature accuracy. can be improved from the conventional level (for example, 20-30 C from room temperature to 600 C) to a higher level (eg 2.5 C from room temperature to 600 C). In the method of forming the liquid mixture mentioned above, a plurality of precursor compounds are mixed in a solvent phase with a complexing compound which contains at least two carboxyl groups as coordination sites and at least one other coordination site to form a solvent mixture. In this solvent mixture, the plurality of precursor compounds is made to react with the above-mentioned complexing compound to form a composite metal complex compound with at least one

coordinated metal element.

  Thus, a liquid mixture is formed wherein is dissolved or dispersed therein a composite metal complex compound. Subsequently, in the same manner as in the manufacturing method mentioned above, a gelatinous precipitate containing the composite metal complex compound or one of its polymers is obtained as the metal salt and the raw material is obtained from this precipitate. . Here, ethylenediaminetetraacetic acid (EDTA) or citric acid is used as the complexing compound

mentioned above.

  Based on the results of the studies of the present inventors, the precursor compounds mentioned above may be one or more organometallic compounds selected from the group of metal alkoxides, metal acetylacetonate or metal carboxylate, or one or more several inorganic metal compounds are selected from the group of nitrate compounds, oxynitrate compounds, chlorides and

oxychloride compounds.

  In addition, it is possible to mix a plurality of precursor compounds containing a metal element in the liquid phase to form a liquid mixture and from this liquid mixture to form a powdered raw material which is a powder composition containing a plurality of metal elements, and then sintering this powdered raw material to obtain a thermistor device as a sintered body (aspect 3). Specifically, this method can be carried out by chemical liquid phase methods as well as by spray pyrolysis methods, pyrolysis methods, freeze drying methods (freeze drying), solvent combustion methods or other physical liquid phase methods, and advantageous effects similar to

  those of the manufacturing method according to aspect 2

above, can be obtained.

  Here, using a transmission electron microscope (TEM) to observe the thermistor device obtained by the manufacturing method of the second or third aspect (the liquid phase method), the size of the main grains of various crystal grains (For example, crystalline grains of Y (Cro0.5Mn0.5) O3 and Y203 in the above-mentioned example above 39Y (Cr0.5Mno, 5) 03.62Y203) were found to be smaller than 1μm, being very small grains of the order of several nanometers (nm) to several hundred nanometers (nm) that were

  uniformly dispersed or mixed in the composition.

  A temperature sensor can be obtained by using such a thermistor device whose dispersion in the composition is suppressed due to

such finesse of grains.

  In particular, when the breaking point of the preparation of the composition of the precursor compounds by a liquid phase method is

At 2775537

  applied to the method of manufacturing a thermistor device consisting of a mixed sintered body of (MlM2) O3.Y203 which is a mixture of the composition (MlM2) O3 and Y203 (where M1 is at least one or more selected elements among the elements of Group 2A or Group 3A of the Periodic Table, with the exception of La, and M2 is at least one or more elements selected from the elements of Groups 2B, Group 3B, Group 4A, Group 5A, of group 6A of Group 7A or Group 8 of the Periodic Table), a method has been invented in which a plurality of precursor compounds containing the elements which constitute the thermistor device and a complexing agent are mixed in the liquid phase to form a liquid mixture, said plurality of precursor compounds and said complexing agent react in said liquid mixture to form a composite complex compound, and then a polymerizing agent is added said composite compound complex to form a polymer, said polymer is dried and heated to obtain the raw material powder constituting the thermistor device, and said powder raw materials are sintered to obtain a device

  thermistor as mixed sintered body of (MlM2) O2.Y203.

  By this method, the plurality of precursor compounds are dissolved or dispersed in the liquid phase so that, in a thermistor device manufactured as a mixed sintered body, the dispersion in the crystal grain composition which constitutes the thermistor device can be deleted. In addition, temperature sensors that use thermistor devices manufactured using this fabrication method will have a smaller dispersion in the device-to-device resistance value, so temperature accuracy can be improved from the conventional level ( for example, 20-30 C, from room temperature to 600 C) at a higher level (e.g.

   1.5-5 C, from room temperature to 600 C).

  It is preferred that citric acid be used as a complexing agent mentioned above and that ethylene glycol be used as the polymerizing agent, and if e is the number of moles of citric acid and f is the total number of moles of elements that make up the thermistor device, so it's best that the relationship

l <e / f <30 be satisfied.

  According to this method of manufacture, in the step of forming the composite complex compound, a complexing reaction occurs in which the ions of the elements which constitute the thermistor device are coordinated at the sites of coordination of the citric acid in the phase. liquid to form the composite complex compound. Subsequently, the composite complex compound is mixed with ethylene glycol as a curing agent, and heated so that they react to form a polymer and the materials

  crude powder is obtained from this polymer.

  In the studies, the present inventors have found that by increasing the concentration of added citric acid to obtain the composite complex compound mentioned above, the composition can be made more uniform. Namely, by adjusting the

  concentration of citric acid in the range mentioned

  above 1 <e / f <30, thermistor devices having good temperature accuracy can be obtained. It should be noted that in the case where the concentration of citric acid is greater than times by weight (a concentration 30 times the total number of moles of the elements constituting the thermistor device), then the phenomenon of association and

At 2775537

  agglutination of the citric acid molecules occurs, and the polymer subsequently obtained becomes a colloidal solution (colloidal sol), so a portion of the constituent elements of the thermistor device will remain indissociated in the liquid phase, creating additional problems such as the divergence in the composition. Therefore, the concentration of citric acid is preferably selected from the range

up to 30 times by weight.

  Considering that the molar fraction of (MlM2) O3 mentioned above is c, and that the mole fraction of Y203 mentioned above is of these mole fractions c and d should preferably

  satisfy the relationships 0.05 <c <1.0, O <d <0.95 and c + d = 1.

  In addition, preferably, the M1 mentioned above may be one or more elements selected from the group Y, C, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, Mg, Ca, Sr, Ba and Sc, while the M2 mentioned above may be preferably one or more elements selected from the group Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Ga, Zr, Nb, Mo, Hf, Ta and W. In addition, the above mentioned M1 may preferably be Y, while the above-mentioned M2 may preferably be Cr and Mn, so the mixed sintered body mentioned above should preferably be Y ( CrMn) O3.Y203. These ranges were selected as the result of the original own studies of the present inventors, and make it possible to obtain a thermistor device capable of measuring a wide range of temperatures of the

room temperature at 1000 C.

  Temperature sensors that include thermistor devices manufactured according to any of the second or third aspect manufacturing methods mentioned above, achieve compositional uniformity and are temperature sensors that utilize temperature sensing devices.

  thermistor with good temperature accuracy.

  Next, with respect to obtaining a device composition by which the thermistor device has a resistance value stability even in the case where it is subject to a reducing environment, the present inventors have thought that if the movement of the oxygen atoms in a reducing environment could be removed from the thermistor device materials that constitute the thermistor device, so the thermistor device itself would not be reduced and its resistance would not change. In addition, the inventors

  concentrated on the formation of an anti-

  reducer that discourages the reaction with oxygen on the surface of the thermistor device and as a result of the experimental studies, they confirmed that changes in the resistance of the device of

  thermistor itself can be removed.

  The fourth aspect of the present invention is based on the results of the studies mentioned above, and consists of a thermistor device characterized by a thermistor part made of thermistor material and an anti-reducer coating made of an anti-reductant material. reducer formed on the surface of this thermistor portion. Here, a precursor material of an organometallic compound is bonded to the surface of the thermistor portion, and then the heating is carried out

  to form the anti-reducer material.

  By means of the fourth aspect mentioned

  above, a device structure is adopted in which the surface portions of the

  thermistor are covered with an anti-

  reducer, thus a device structure that has a resistance value stability even in

  the case in which the thermistor device itself

  even is exposed to a reducing environment can be provided. Normally, when a thermistor device is used in a temperature sensor, a pair of electronically conductive elements (e.g., metal lead wires) is used to maintain electrical continuity with the thermistor device to sense the temperature. from the change in the resistance of the device. In the case where the thermistor device of the fourth aspect is used as a temperature sensor, a structure is adapted whereby the pair mentioned above electrically conductive elements penetrates the anti-reducer coating which is the surface layer, and between in contact with the thermistor part inside.

  For this reason, in order to avoid a short

  circuit between the pair of electrically conductive elements, the anti-reducer coating should preferably be an electrical insulator. On the basis of

  studies of the present inventors, the anti-

  reducer which constitutes the anti-reducer film should have a greater electrical resistance than the thermistor materials which constitute the part of

thermistor.

  On the basis of the studies mentioned above, a

  anti-reducer material which constitutes the anti-aging film

  The reducing agent should not allow oxygen to pass through and its resistance value is preferably high, and the results of the studies of the present inventors have found that the anti-reducing material should preferably contain one or more elements selected from groups of Y (yttrium), Al (aluminum) and Si (silicon). This material is preferably a material selected from the groups Y203 (yttria), Al2O3 (aluminum oxide), SiO2 (silicon oxide), Y3A15012 (YAG: yttrium-aluminum-garnet),

3A12032SiO2 (mullite) and Y2SiO5.

  A specific example of the fourth aspect is, in a thermistor device used at temperatures of 200 C and meeting reducing environments, a thermistor device which comprises

  stability of resistance value.

  The thermistor device mentioned above

  made by forming the anti-reducer coating mentioned above made of the anti-reducer material mentioned above on the surface of this thermistor portion, may be manufactured by forming a precursor of the anti-reducer material on the surface of the thermistor portion, and then heating it to form the anti-reducer coating mentioned above on the

  surface of the thermistor part.

  An organometallic compound can be used as the precursor mentioned above. Said organometallic compound is preferably an alkoxide (metal alkoxide) containing one or more elements

  selected from the group of Y, Al and Si.

  By immersion coating the thermistor part mentioned above with a solution

  containing the organometallic compound mentioned in

  above, the precursor may be applied to the surface of the thermistor portion mentioned above. By this method, the precursor can be applied more easily than by spray coating or centrifuge.

BRIEF DESCRIPTION OF THE FIGURES

  Figure 1 shows a structural diagram of the thermistor device of an example of the

present invention.

  Figure 2 shows a cross-sectional structural diagram of a temperature sensor that uses the

  thermistor device of Figure 1.

  Figure 3 shows a section along A-A of Figure 2. Figure 4 shows a diagram of the manufacturing process for the thermistor device of Figure 2.

  Example 1 of the present invention.

  Figure 5 shows a diagram of the manufacturing process for the thermistor device of

  Example 2 of the present invention.

  Figure 6 shows a diagram of the manufacturing process for the thermistor device of

  Example 3 of the present invention.

  Figure 7 shows a diagram of the manufacturing process for the thermistor device of

  Example 4 of the present invention.

  Figure 8 shows a diagram of the manufacturing process for the thermistor device of

  Example 5 of the present invention.

  Figure 9 shows a diagram of the manufacturing process for the thermistor device of

  Example 6 of the present invention.

  Figure 10 shows a diagram of the manufacturing process for the thermistor device of

  Example 7 of the present invention.

  Fig. 11 shows a diagram of the manufacturing process for the thermistor device of

  Example 8 of the present invention.

  Figure 12 shows a diagram of the manufacturing process for the thermistor device of

  Example 9 of the present invention.

  Figure 13 is a diagram of the manufacturing process for the thermistor device of

  Example 10 of the present invention.

  Figure 14 is a diagram of the manufacturing process for the thermistor device of

  Example 11 of the present invention.

  Figure 15 shows a diagram of the manufacturing process for the thermistor device of

  Comparative Example 3 of the present invention.

  Figure 16 is a diagram of the manufacturing process for the thermistor device of

  Example 13 of the present invention.

  Figure 17 shows a diagram of the manufacturing process for the thermistor device of

  Example 14 of the present invention.

  Figure 18 shows a diagram of the manufacturing process for the thermistor device of

  Comparative Example 4 of the present invention.

Fig. 19 shows a diagram of the manufacturing process for the thermistor device of

  Example 16 of the present invention.

  Figure 20 shows a diagram of the manufacturing process for the thermistor device of

  Example 17 of the present invention.

  Figure 21 is a diagram of the manufacturing process for the thermistor device of

  Comparative Example 5 of the present invention.

  Figure 22 shows a diagram of the manufacturing process for the thermistor device of

  Example 19 of the present invention.

  Figure 23 shows a diagram of the manufacturing process for the thermistor device of

  Example 20 of the present invention.

  Figure 24 is a diagram of the manufacturing process for the thermistor device of

  Comparative Example 6 of the present invention.

  Figure 25 is a diagram of the manufacturing process for the thermistor device of

  working examples 18-23 of the present invention.

  Figure 26 shows a schematic section of the thermistor device of an embodiment

  preferred embodiment of the present invention.

  Figure 27 shows a sectional view of a temperature sensor that uses the device of

thermistor of Figure 26.

  Figure 28 shows a sectional view according to

A-A of Figure 27.

  Figure 29 is a diagram of the manufacturing process for the thermistor device of

  Examples 24 and 25 of the present invention.

  Figure 30 is a diagram of the manufacturing process for the thermistor device of

  Examples 26 to 30 of the present invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENT

  (First aspect) (Embodiment 1) In the perovskite (M1M2) O3 material composition of the present invention, for example, the M1 element may be selected from Mg, Ca, Sr, Ba or other elements. of Group 2A of the Periodic Table, or among Y, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho,

  Er, Yb, Sc or other elements of Group 3A except La.

  In addition, for example, the element M2 may be selected from Zn in Group 2B; A1 and Ga in Group 3B; Ti, Zr and Hf in Group 4A; V, Nb and Ta in Group 5A; Cr, Mo and W in Group 6A; Mn, Tc and Re in Group 7A; or from Fe, Co, Ni, Ru, Rh,

  Pd, Os, Ir and Pt in Group 8, respectively.

  Here follows a description of the method of

  manufacture of mixed sintered bodies of (M1M2) O3 Y203.A1203 and (M1M2) O3.A1203. The manufacturing process can be broadly divided into a first preparation step in which a calcine (M1M2) O3 or (M1M2) O3.Y2O3 is obtained and in a second preparation step in which the calcine thus obtained is then combined with A1203 etc. . (A1203, or Y203 and A1203), then the thermistor device is obtained as a

  mixed sintered body in the prescribed form.

  In the first preparation step, the raw materials for M1 and M2, which are oxides of M1 (MlOx) and M2 oxides (M20x) are compounded (Formulation 1), mixed and molded (mixing step) and then

  subjected to calcination (for example at about 1000 C -

  1500 C) (calcination step) to obtain a calcine.

  Then, in the second preparation step, the calcine thus obtained is combined with Al 2 O 3, etc., to give the resistance value and the desired resistance-temperature coefficient (formulation 2). The mixture obtained in formulation 2 (a mixture of calcine and Al 2 O 3, etc.) is ground (milling step), integrated with Pt reducing wires or the like, molded into the desired shape in a mold (step of

  molding) and sintered (for example, at about 1400 C -

  1600 C) (sintering step) to obtain the device

  thermistor in the form of a mixed sintered body.

  It should be noted that in the case where Y is included in M1i in the mixed sintered body of (M1lM2) O3.Y203.A1203, Y203 can be added in advance in formulation 1 as an oxide of M1 in the first stage. of preparation, and then pass through the mixing and calcining steps to obtain (MlM2) O3.Y203. Subsequently, an appropriate amount of A1203, etc. is mixed with the calcine (MlM2) O3.Y203 in order to produce a mixed sintered body which

  finally has the desired composition ratio.

  In passing, adding SiO2 and at least one of CaO, CaCO3 or CaSiO3, as sintering aids, mixture of calcine and Al 2 O 3, etc. in the formulation step 2 mentioned above, the sintered density can be increased again. This will ensure that the correct resistance of the thermistor device will be more stable and that the dispersion of the resistance value with respect to fluctuations in

  the sintering temperature will be reduced.

  The resulting thermistor device is a mixed sintered body in which the perovskite (M1M2) 03.Y203 and A1203 (or A1203 and Y203) compounds are uniformly mixed and bound to their grain boundary. The resulting thermistor device was placed in a typical temperature sensor assembly to obtain a temperature sensor. Then, the temperature sensor was placed in a high temperature oven and the resistance value and the resistance-temperature coefficient λ were measured over the temperature range from room temperature (for example 27 C) to 1000 C , and also the rate of change of resistance AR1 on the heating of the ambient temperature to 10000C or equivalent, has been

measured.

  Here, f is expressed as (K) = ln (R / R0) / (1 / K-1 / K0). It should be noted that in indicates the natural logarithm, while R and R0 represent the resistance value of the thermistor device at high temperatures, ambient temperature (300K) and

  1000 C (1273K), and respectively in the atmosphere.

  In addition, the rate of change of the resistance AR1 represents the rate of change of the resistance of the temperature sensor in a high temperature endurance test in which it is left for hours at 1100 C in the atmosphere, expressed by the formula 1: AR1 (%) = (R't / Rt) x10-100. It should be noted that Rt represents the initial resistance value at a stipulated temperature t (for example 500 C), and R't is the temperature resistance value stipulated t

  after being left for 100 hours.

  As a result, in the temperature range from room temperature to 1000 C, Rt is found to be variable between 50 n and 100 kΩ, and P adjustable in the range of 2000-4000K, and AR1 is found to be stable at a level of roughly several% (see Table 1). Here, in order to obtain the different values of Rt, 3 and AR 'more safely, the mole fractions a and b in a (M1M2) O3.bAl2O3 and a (M1M2) O3.b (A1203, Y203) have preferably the relations 0.05 <a <l, 0, 0 <b 0.95, and

a + b = l.

  Therefore, by this embodiment, it is possible to provide a wide range thermistor device which is capable of detecting temperatures over a wide temperature range from room temperature to 1000 C, and which has stable characteristics. with a small change in its resistance value throughout the heating of the

  room temperature at 1000 C or equivalent.

  In addition, the temperature coefficient

  P resistance is adjustable in the range of 2000-4000K, smaller than that of conventional thermistor devices, so the dispersion in the resistance value accompanying the fluctuations in the

  temperature can be made smaller.

  (Embodiment 2) This embodiment 2 is a method of manufacturing the mixed sintered body according to embodiment 1 mentioned above, and comprises first and second preparation steps in the same manner as the first method of manufacture. mentioned above in embodiment 1, but

is characterized as follows.

  That is, in the step in which the mixture of calcine and Al 2 O 3 compounds in formulation 2 is ground (grinding step), the average grain size of the mixture after grinding is brought below the grain size. average of A1203, etc. before

  mixed. Here follows a description mainly around

from this point.

  The manufacturing method of this embodiment 2 has been updated, when, by examining the temperature accuracy of a temperature sensor incorporating the thermistor device made by the manufacturing method of Embodiment 1 mentioned above. , results indicated that there was a dispersion in sensor temperature accuracy in sensor. Here, the method of evaluation of the temperature accuracy was carried out by the method

following, as an example.

  On the basis of resistance value data-

  temperature from a large number of temperature sensors (eg 100 units), the standard deviation a (sigma) of the resistance value at a stipulated temperature (eg 500 C) was calculated, and six times the standard deviation C is taken as the amount of dispersion of the resistance value (on both sides). The value of this dispersion amount of the resistance value when converted to a temperature and divided by two, becomes the value A, which is evaluated in terms of the term "temperature accuracy of A C". As a result, the temperature accuracy of + A C was found as

having a dispersion of 20-30 C.

  On the other hand, when the thermistor materials were observed by scanning electron microscope (SEM), electron probe microanalysis (EPMA) and other methods, in the embodiment 1 mentioned above, the average grain size of the calcine obtained from the first preparation step (for example, 2-5 pmn in the case of (M1M2) 03) is found to be larger than the average grain size of A1203, etc. (eg, 0.6 μm or less in the case of A1203) with which it can be mixed. Thus, both are not uniformly mixed and there is dispersion in the composition distribution of the mixed sintered body. Thus, the average diameter of the mixture (a mixture of calcine and Al 2 O 3, etc.) after mixing and grinding in the second method of manufacture of the first embodiment above, has been varied in a variety of ways, and the relationship between the average particle size

  and the temperature accuracy of _A C was examined.

  As a result, it has been found that in the grinding step in the second method of manufacture, if the average particle size is brought below the average grain size of A1203, etc. before mixing, the temperature accuracy can be

  decreased below 10 C (refer to Table 2).

  For this purpose, a media mixer or equivalent may be used as a grinding means to give a medium or fine grain size. In addition, beads made of ZrO2 (for example, with a diameter of 0.5 mm) can be used as the medium of

  grinding in the media mixer.

  By means of this embodiment 2, the step of grinding the second preparation step is supposed to crush the calcine and A1203, etc. in a fine way to achieve uniform mixing and reduce fluctuation in the composition of the mixed sintered body, so that the dispersion in the resistance value of the device

  Thermistor can be reduced.

  Therefore, in addition to the effects

  advantage of the manufacturing method mentioned above.

  In Embodiment 1, it is possible to provide a wide range thermistor device that is able to perform better sensor accuracy (smaller dispersion in temperature accuracy from sensor to sensor) in the range of

  temperature from room temperature to 1000 C.

  (Embodiment 3) This embodiment 3 is a method of manufacturing the mixed sintered body according to the first embodiment mentioned above, and comprises first and second preparation steps in the same manner as the first method of manufacture. mentioned above in embodiment 1, but

is characterized as follows.

  That is, this embodiment is characterized in that during the step in which the M1 oxide and the M2 oxide are combined for the formation 1 and then mixed and ground (mixing step), the M2 material is mixed and ground with the material Ml and the dimension

  average grain of this ground mixture is brought to

  below the average grain size of the Ml materials before mixing and above 0.5 pim and then it is

calcined to obtain calcine.

  Here, grinding in the grinding mixture mentioned above (mixing step) can be carried out by a media mixer as described in the embodiment mentioned above 2. Then, in the second preparation step, the calcine is combined with A1203 etc. and ground, integrated with Pt lead wires or the like, molded into the desired shape in a mold and sintered to obtain the thermistor device in the form of a sintered body

mixed.

  This embodiment is intended to effect more uniform mixing of the composition through uniform fine grinding of materials M1 and M2, then reduce dispersion in the calcine composition and remove the presence of unreacted raw materials, thereby reducing the dispersion in the

  resistance value of the thermistor device.

  Therefore, in addition to the effects

  merits of the manufacturing method mentioned above.

  In Embodiment 1, it is possible to provide a wide range thermistor device which may have better sensor accuracy (smaller dispersion in temperature accuracy from sensor to sensor) in the range of leaving temperature

  from room temperature to 1000 C.

  It should be noted that grinding in the grinding step of the second preparation step can be carried out by a ball mill or the like, but a media blending mill or the like can be used in the same manner as in the blast mode. realization 2 mentioned above. If this is done, in addition to the meritorious effects of this embodiment, are added the meritorious effects of the above-mentioned embodiment 2, wherein the grinding step of the second preparation step is supposed to grind the calcine and the A1203 etc. finely to achieve uniform mixing and to reduce fluctuation in the composition of the mixed sintered body in the following molding and sintering steps, so the dispersion in the resistance value of the thermistor device can be further reduced. Moreover, in a temperature sensor that uses a wide range thermistor device according to embodiments 2 and 3, the temperature accuracy is suppressed to 10 C or less, so they are well suited for use in controllers of cards that require a high degree of temperature accuracy, such as in temperature monitors for exhaust oxygen sensors

automobiles.

  (Second aspect) (Embodiment 4) The thermistor device of this embodiment is fitted to a thermistor device that is used in a temperature sensor that can sense temperatures in a wide range of room temperature to 1000 C (Thermistor device called "wide range"). Temperature sensors that use the thermistor device of this embodiment can for example be used as a temperature sensor to detect

  automobile exhaust temperatures.

  Figure 1 shows a structural diagram of the thermistor device 1 of this embodiment. The thermistor device 1 is made of a sintered body formed generally in a specified form (cylindrical in this example). This thermistor device 1 consists of an oxide sintered body of a plurality of metals such as Y, Sr, Cr, Fe, Ti or equivalent, which are mixed at a prescribed composition level. Specific examples may be aY (Cr0.5MnO5) 03.bY2O3, aY (Cr0.5Mn0.5) 03.bA1203, (Y0, O9Ca0.1) (CrO, 75Fe0o, 2Tio, O5) O3, (AlO7Cr0O2FeO0, 1) 203.MgO.CaO or of

other compositions.

  In Fig. 1, references 11 and 12 indicate a pair of conductive films (signal acquisition electrodes made of platinum to sense the temperature from the change in the resistance of this thermistor device 1. Although this part is not not shown, the two conductive films 11 and 12 are buried inside the thermistor device 1 at a distance fixed far from each other, generally parallel to the longitudinal axis of the cylinder of the thermistor device 1. From addition, their non-buried portions extend outwardly from one end of the

thermistor 1.

  Then, the thermistor device 1 with the fixed conductor wires 11 and 12 is assembled in a temperature sensor 100 as shown in FIG. 2. FIG. 2 is a sectional view of the temperature sensor 100. FIG. at level AA of Figure 2. Here, reference 2 is a metal cover having the shape of a cylinder with a bottom and the reference 3 is a pipe of the cylindrical metal. The lid of the metal 2 is provided on the outer rim of the metal pipe 3 by means of claws or the like so that the inside of the metal lid 2 is a sealed space. In addition, the thermistor device 1 with the fixed conductor wires 11 and 12 is disposed at

  inside the metal cover 2.

  In addition, the outer ends of the wires 11 and 12 are electrically connected to the leads 31 and 32 for exchanging signals with external circuitry (e.g., an automobile exhaust control unit (ECU) not shown). . The locations of the connections of the conductive wires 11, 12, 31 and 32 may be either inside or outside the metal pipe 3. It should be noted that, as shown in FIG. metal pipe 3 is filled with a magnesia powder 33 to insure the insulation of the conductor wires 31 and 32 inside the pipe of

metal 3.

  The temperature sensor 100 may be disposed with the tip of the metal cover 2 in the passage of an automobile exhaust system to detect the temperature of the exhaust gas. In particular, the temperature of the exhaust gas can be determined by using the characteristic R-T of the thermistor device, and the electrical signal indicating the temperature of the exhaust gas which is acquired through the conductive wires 11, 12, 31, and 32

  by the external circuitry mentioned above.

  Next, we will describe the method of manufacture of the thermistor device 1. It should be noted that details will be provided in the examples given later. The manufacturing method of this embodiment can be broadly divided into a first step (step of manufacturing the raw powder material) in which the powdered raw material containing the metal elements in the stipulated composition which constitutes the thermistor device 1 , is obtained by means of a liquid phase method, and a second step (thermistor molding step) in which the powdered raw material thus obtained, is granulated, dried, molded, sintered and so on for

  get the thermistor device 1.

  First, in the first step, a plurality of precursor compounds that contain metal elements that constitute the thermistor device 1 are mixed in the liquid phase to form a liquid mixture of the stipulated composition, and a salt precipitating agent. metal is added to this liquid mixture to precipitate a gelatinous precipitate containing a plurality of metallic elements. Then, by drying and heating this precipitate, the powdered raw material which is a powder composition containing a plurality of elements

metal is formed.

  Here, the precursor compounds mentioned above

  may be metal alkoxides, metal acetylacetonates, metal carboxylates or other organometallic compounds, and examples include: triethoxyttrium (Y (OC 2 H 5) 3),

  diethoxymanganese (Mn (OC2H5) 2), tris (2,4-

  pentadione) chromium (Cr [OC (CH3) CHCOCH3] 3) or equivalent.

  In addition, the precursor compounds may also be nitrate compounds, oxynitrate compounds, chlorides, oxychlorides or other inorganic metal compounds, and included examples of yttrium nitrate (YNO 3) 3.6H 2 O), nitrate calcium (Ca (NO3) 2.4H2O), chromium nitrate (Cr (NO3) 3.9H2O), iron nitrate (Fe (NO3) 3 .9H2O), oxynitrate

  titanium (5TiO2.N2O5.6H2O) or equivalent.

  The solvent in which these precursor compounds are dissolved or dispersed can be selected in consideration of the solubility and subsequent treatment (drying, etc.), and examples of solvents which can be used include ethanol solvent blends and the like. isopropyl alcohol or other organic solvents, or deionized water or equivalent. In addition, the metal salt precipitant may be suitably selected in consideration of the solubility of the precursor compounds in the solvent mixture, the concentration, the pH value and other conditions so that the precipitate is precipitated effective. Examples of the precipitation agent include deionized water, sodium bicarbonate, ethylene glycol or the like. In addition, in forming the aforementioned liquid mixture above the precursor compounds, the precursor compounds mentioned above can be mixed in the liquid with a complexing compound to form a liquid mixture. By which, this complexing compound reacts with the aforementioned plurality above precursor compounds to form a composite metal complex compound in which at least one or more metal elements are coordinated, and after polymerization of the composite metal complex compound, a precipitate of this compound composite metal complex and its

  polymer can be obtained as the metal salt.

  Here, the complexing compound mentioned above should preferably contain at least two carboxyl groups as coordination sites and at least one other coordination site. Namely, by having three or more coordination sites, it is able to coordinate at least one metallic element and the remaining coordination sites can be used to

  to form chains in the polymerization reaction.

  Examples of such complexing compounds include ethylenediaminetetraacetic acid (EDTA) and

citric acid.

  In addition, the gelatinous precipitate of metal salts precipitated from the liquid mixture of the precursor compounds can be dried and heated (or calcined) to remove any moisture or impurity (organic compounds or gases, etc.) that may be present. In this way, it is possible to obtain a powdered raw material which is a powder composition containing the stipulated composition of metallic elements to constitute the thermistor device 1. Then, during the second step, this powdered raw material is used to complete the

thermistor device 1.

  In the second step, the powdered raw material thus obtained is granulated, assembled with the conductive wires 11 and 12 of Pt or equivalent, molded in the desired form and sintered (at a temperature of generally 1400 C to 1600 C). Thus, as shown in FIG. 1, a thermistor device 1 consisting of a sintered body with the fixed conductor wires 11 and 12 is obtained. Then this thermistor device 1 is assembled in the temperature sensor 100 as shown on

Figure 2.

  The evaluation of the resistance characteristics of the thermistor device 1 is carried out in the state in which it is assembled in the temperature sensor 100. The dispersion of the resistance value of the thermistor device 1 is evaluated as the temperature accuracy of the temperature sensor 100. The temperature sensor 100 is placed in an oven and the resistance value and the resistance-temperature coefficient P have been measured over the temperature range from room temperature (for example, 27 C) to 1000 C. Here, 3 has the same

  meaning that in the embodiment 1.

  The method of evaluating the temperature accuracy is as follows. On the basis of the data of the temperature values - resistance from temperature sensors, the standard deviation (sigma) of the temperature resistance value of 600 C) has been calculated, and six times the standard deviation a is taken. as the amount of dispersion of the resistance value (on both sides). The value of this dispersion amount of the resistance value when converted to a temperature and divided into two becomes the value A, which is evaluated as the temperature accuracy of + A C. As a result of this evaluation per 100 units of the thermistor device 1, the temperature accuracy was found to be stable at a level of + 2-5 C in the temperature range at 600 C (see

Figure 5).

  This level of temperature accuracy is in a range quite adequate for systems that require a high degree of accuracy as given

  in the description of the second object of this

  invention. Therefore, by means of this embodiment, the dispersion of the resistance value of the thermistor device can be reduced below the conventional level of temperature accuracy (20-30 C from room temperature to 600 C; Table 6). In addition, the temperature sensor 100 that uses the thermistor device 1 of this embodiment is capable of achieving better temperature accuracy than the conventional level in

  the range from room temperature to 1000 C.

  By this embodiment, since the plurality of precursor compounds dissolve or are dispersed in the liquid phase, they can be mixed in the desired composition ratio in the fine-grain state of the atomic or molecular order, such as the different precursor compounds can be mixed uniformly. Therefore, the powdered raw material contains the metal elements mixed with the desired atomic or molecular order composition ratio, so that the thermal reactions in the subsequent heating process are made uniform. Therefore, finally, in a thermistor device manufactured in the form of a sintered body, the dispersion in the composition of the crystal grains which constitute the

  Thermistor device can be removed.

  Here, when an analytical electron microscope (AEM) was used to examine the crystalline phases of the grains of the crystalline phases that predominantly dominate the resistance value, and a compositional analysis was performed, virtually no conventional dispersion in the composition from the ideal composition was noticed, the uniformity of the compositions at the level of the atomic or molecular order was found. In addition, on the use of an electron-transmitting microscope (TEM) to observe the thermistor device 1, the average grain size of the different crystal grains was found to be smaller than 1 μm, being very small. fine grains, of the order of several nanometers to several hundred nanometers which were uniformly

  dispersed / mixed in the composition.

  (Embodiment 5) This embodiment presents the method of

  manufacture of the thermistor device mentioned in

  1, and specifically a thermistor device consisting of a mixed sintered body of (MlM2) O3.Y203 which is a mixture of the composition (MlM2) O3 and Y203 (where M1 is at least one or more elements selected from the elements of Group 2A or Group 3A of the Periodic Table except the element La, and M2 is at least one or more elements selected among the elements of Group 2B, Group 3B, Group 4A, Group 5A, Group 6A, Group 7A or

Group 8 of the Periodic Table).

  In this mixed sintered body of (M1M2) O3.Y2O3, taking the mole fraction of (MlM2) O3 as c, and the mole fraction of Y203 mentioned above as d, these mole fractions c and d should preferably satisfy the relationships 0.05 <c <1.0,

0 <d <0.95 and c + d = 1.

  By adopting these relationships, the temperature-resistance coefficient 3 described in embodiment 1 above can be made adjustable in the range 2000-4000K, so dispersion in the resistance value accompanying temperature fluctuations can be made more small, and so a thermistor device 1 that is able to measure temperatures over a wide range starting from the

  room temperature at 1000 C can be obtained.

  In addition, in order to obtain a thermistor device 1 which is capable of measuring the temperature over a wide range from room temperature to 1000 C, M1 should preferably be one or more elements selected from the group Y, Ce, Pr , Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, Mg, Ca, Sr, Ba and Sc, while M2 should preferably be one or more elements selected from the group Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Ga, Zr, Nb, Mo, Hf, Ta and W. In addition, the manufacturing method of this embodiment comprises the following steps: a first step (step of manufacturing the material powdered crude) in which a plurality of precursor compounds containing the elements M1, M2 and Y which constitute the thermistor device 1 (hereinafter referred to as the "constituent elements") and a complexing agent are mixed in the liquid phase to form a liquid mixture, said plurality of precursor compounds and said ag complex-forming ent react in said liquid mixture to form a composite complex compound in which said components are coordinated, then a polymerizing agent is added to said composite complex compounds to obtain a polymer containing said constituent elements, and said polymer is dried and heated to obtain powdered raw materials that

  contain said constituent elements.

  Citric acid can be used as a complexing agent mentioned above and ethylene

  glycol can be used as the polymerizing agent.

  The citric acid complexing agent has a high solubility, so the composite complex compound can be prepared at a high concentration and thus the water content of the liquid mixture can be lowered, thereby reducing the heating energy requirements for drying and heating treatment

in the following steps.

  In addition, by increasing the concentration of citric acid, the composition of the thermistor can be made even more uniform. This is because the dissociation of the elements of the composite complex compound from the liquid mixture can be suppressed, and the dispersion of the thermistor device composition thus obtained can be reduced. According to the studies made by the present inventors, it has been found that if the number of moles of citric acid is taken as e and the total number of moles of the elements M1, M2 and Y which constitute the thermistor device is taken as f , then by synthesizing the raw materials so that the number of moles e and f are such that the relation 1 <e / f <30 is satisfied, a thermistor device 1 comprising

  a good temperature accuracy can be obtained.

  It should be noted that up to a citric acid concentration of 20 times by weight, the polymer obtained is a gelatinous viscous liquid, but if the concentration of citric acid is increased to 30 times by weight, then the polymer does not become a gelatinous viscous liquid, but rather a colloidal solution

dispersed in the liquid.

  This is because if the concentration of citric acid is greater than 30 times by weight, then the phenomenon of association and agglutination of the citric acid molecules occurs, and the polymer obtained thereafter becomes a solution colloidal, and the added citric acid can not be effectively used in the complex formation, so a portion of the constituent elements of the thermistor device will remain undissociated in the liquid phase. For this reason, this creates additional problems, such as compositional divergence from the ideal composition, and divergence in composition may even tend to become more important. Therefore, the concentration of acid

  citric should satisfy the relationship mentioned above.

  above. Further, in the same manner as in embodiment 1 above, this thermistor device 1 is assembled in a temperature sensor 100 and its resistance characteristics (resistance value from room temperature to 1000 C, coefficient of resistance-temperature f, temperature pressure AC) were evaluated. As a result of the evaluation of the temperature sensor 100 of this embodiment, the temperature accuracy from room temperature to 600 C has been found to be stable at a level of 1.5-8 C ( see Table 7), and the temperature accuracy in the range from room temperature up to 1000 C has been found

  as being better than conventional levels.

  Incidentally, in this embodiment too, since the plurality of precursor compounds dissolve or disperse in the liquid phase, the same meritorious effects as in the above embodiment 4 are obtained and, as a result, in one embodiment Thermistor device manufactured in the form of a sintered body, the dispersion in the composition of the crystalline grains constituting the thermistor device can be suppressed. AEM and TEM observations have also shown that results similar to those of the above embodiment 4 were obtained. (Fourth aspect)

  Here follows a description of the fourth aspect of

  the present invention as implemented by a thermistor device which has a resistance value of 50Ω to 100kΩ in the temperature range from room temperature to 1000C (hereinafter referred to as a thermistor device) wide range). The thermistor device of this embodiment can, for example, be used in a temperature sensor to detect the temperature of the exhaust gas of an automobile. Figure 26 is an explanatory diagram showing the schematic view in section of the

  thermistor device 1 of this embodiment.

  The thermistor device 1 consists of a thermistor portion 13 made of thermistor materials having a generally specific shape and an anti-reduction coating 14 made of an anti-reducing material.

  formed on the surface of this thermoresistance portion 13.

  Here, as the heat-resistant materials which constitute the heat-resistance part 13, on the basis of the studies made by the present inventors, a mixed sintered body formed by mixing two types of compounds: a perovskite-like material (oxide) which has a resistance value relatively low and a material that has a relatively high resistance value is preferable in order to obtain a

  heat-resistant device with wide range.

  Studies of the present inventors of various perovskite materials have shown that the materials should preferably have the composition (M1M2) O3 (where M1 is at least one or more elements selected from Group 2A or Group 3A elements of the Periodic Table). excluding La, and M2 is at least one or more items selected from the Group 2B, Group 3B, Group 4A, Group 5A, Group 6A, Group 7A or Group 8

Periodic table).

  It should be noted that La is highly hygroscopic and reacts with moisture in the atmosphere to produce unstable hydroxides that could damage the thermistor device, so it does not

must not be used as Mi.

  In addition, like the various elements in (M1M2) O3, M1 is preferably one or more elements selected from Mg, Ca, Sr, Ba (Periodic Table Group 2A), Y, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, Sc (Group 3A), while M2 is preferably one or more elements selected from Zn (Group 2B), Al, Ga (Group 3B), Ti, Zr, Hf (Group 4A) ), V, Nb, Ta (Group 5A), Cr, Mo, W (Group 6A), Mn, Tc, Re (Group

  7A), Fe, Co, Ni, Ru, Rh, Pd, Os, Ir or Pt (Group 8).

  As a material having a relatively high resistance value, according to the present inventors' studies, Y 2 O 3 (yttrium oxide) or Al 2 O 3 (aluminum oxide), which have a relatively high resistance value and which stabilize the resistance value of the thermistor, have been found

  as being advantageously usable.

  The heat-resistant portion 13 may be made of a mixed sintered body of (M1M2) O3.Y2O3 obtained in

  sintering mixture of (MlM2) O3 and Y203 mentioned above

  above, or the heat-resistant portion 13 may be made of a mixed sintered body of MlM2) O3.A1203 obtained in

  sintering mixture of (MlM2) O3 and Al2O3 mentioned above.

above.

  On the other hand, the anti-reducer coating 14 should not allow oxygen to pass through

  through and should be made of an anti-

  reducer which has a higher resistance value than that of the heat-resistant material which constitutes the heat-resistant part 13 (that is to say the mixed sintered body mentioned above). The anti-reducing material mentioned above should preferably contain one or more elements selected from the group of Y, Al and Si. This composition is preferably a composition selected from the group of Y 2 O 3 (yttria), Al 2 O 3 (oxide of aluminum), SiO2 (silicon oxide), Y3A15012 (YAG), 3A1203. 2SiO 2 (mullite) and Y 2 SiO 5. As shown in Fig. 26, a pair of conductive links made of platinum or equivalent (electrically conductive elements) 11, 12 is provided on the heat-resistant device 1 in order to detect the temperature from the change in the resistance of the device. The two conductive wires 11 and 12 penetrate the anti-reducer coating 14 with a

  end buried in heat-resistant part 13.

  It should be noted that, although this is not shown, the part of the two conductive cables 11 and 12 buried in the heat-resistant part 13 are arranged at a fixed distance far from each other. As described above, the anti-reducer material has a greater electrical resistance than the heat-resistant material which constitutes the heat-resistant portion 13 and is a resistor, so the

  anti-reducer coating 14 can avoid a short

  circuit between the two conductive wires 11 and 12.

  The thermistor device 1 mentioned above

  top with fixed leads 11 and 12 is assembled in a temperature sensor 100 as shown in Fig. 27. Fig. 27 is an explanatory diagram showing the inside of the cover

  of metal temperature sensor 100 in perspective.

  Figure 28 is a sectional view at A-A of Figure 27. In Figures 27 and 28, reference numeral 2 is a cylindrical metal cover and numeral 3 is a metal pipe. The ends of the conductive wires 11 and 12 with respect to the buried ends in the thermistor portion 13 are electrically connected to the wires 31 and 32 in order to exchange signals with the external circuitry (for example, a control unit of Automotive Exhaust (ECU) The locations of the connections among the conductive cables 11, 12, 31 and 32 may be either inside or outside the metal pipe 3. As shown in Figure 28, the The interior of the metal pipe 3 is filled with magnesia powder 33 to insure the insulation of the wires 31 and 32 inside the metal pipe 3. The metal cover 2 is secured to the outer edge of the pipe. metal 3 by means of claws or equivalent, so that the inside of the lid of

metal 2 is a sealed space.

  Next, the method of manufacturing the thermistor device 1 will be described. First, the case of using a mixed sintered body of (MlM2) 03.Y203.A1203 as heat-resistant part 13 will be described. The manufacturing method in this case can be broadly divided into a first and a second step. First, the raw materials for M1 and M2, which are MI oxides (MlOx) and oxides of M2 (M20x) and Y203 (which may be the same as MlOx), are combined (Formulation 1), mixed and ground into using a media mill-mixer or equivalent (mixing step) and then subjected to calcination at a temperature of about 1100 C to about 1300 C) (calcination step). A composition of (MlM2) 03.Y203 is obtained as calcine. This is the end of the first

preparation stage.

  Then, the appropriate amount of this calcine thus obtained is weighed (formulation 2) and the weighed calcine is ground (grinding step), integrated with Pt conductive wires or the like, molded into a desired shape in a mold (molding step ) and sintered at a temperature of about 1400 C to about 1600 C (sintering step). In this way, a mixed sintered body (heat-resistant part

  13) with fixed cables 11 and 12 is obtained.

  Next, the surface of the heat-resistant portion 13 is dip-coated with the precursors of the anti-reduction material in the liquid state (dip coating step) and the sintering is conducted at a temperature of approximately 1400 C to approximately 1600 C (sintering step). Thus, a thermistor device 1 with an anti-reduction coating 14 formed on its surface is obtained. This is the end of the

second stage of preparation.

  Then, the case where a mixed sintered body of (M1M2) O3.A1203 is used as heat-resistant part 13 will now be described. The manufacturing method in this case can also be widely divided into first and second stages. However, the difference is that after the calcine has been obtained in the first preparation step, the calcine is combined with A1203 in the formulation 2 so that the

  resistance value and resistance coefficient

  desired temperatures are obtained.

  First, in the first preparation step, starting with the raw materials for M1 and M2, formulation 1, the mixing step and the calcining step are carried out to obtain

  the composition (MlM2) O3 as calcine.

  Then, the appropriate amount of this calcine thus obtained is weighed and combined with A1203 so that the desired resistance value and temperature-resistance coefficient are obtained (formulation 2). The weighed calcine is subjected to the grinding step, the molding step and the sintering step to obtain a mixed sintered body (thermistor portion 13) with fixed wires 11 and 12. Then, the dip coating step and the coating forming step are carried out to obtain the

thermistor device 1.

  It should be noted that in the case of (MlM2) O3.Y203 also, it is possible to obtain (M1M2) O3 as calcine in the first preparation step, and to combine the calcine (MlM2) O3 with Y203 for the formulation 2 in the second preparation step, so that the resistance-temperature coefficient and the desired resistance value are obtained, and continuing to the sintering step to obtain a

  mixed sintered body of (MlM2) O3.Y203.

  During the immersion coating step mentioned above, a liquid containing an organometallic compound may be used. An alkoxide (metal alkoxide) containing one or more elements selected from the group of Y, Ai and Si may be

  used as an organometallic compound.

  By performing the dip coating using the liquid containing these organometallic compounds, the organometallic compounds that are the precursors of the anti-reducer material can be applied to the surface of the heat-resistant portion 13. Thus, the anti-reducer coating 14 makes Y203, A1203, Y3A15012, mullite, Y2SiO5 or equivalent during the film forming step, is

  formed as an anti-reducing material.

  In formulation 1 and formulation 2 mentioned above, it is preferable to add a sintering aid in order to improve the sintering characteristics and equivalent of the mixed sintered body. From the studies of the present inventors on various sintering aids, it has been found that the use of at least one sintering aid selected from the group of CaO, CaCO3, CaSiO3 or SiO2 is preferable in order to obtain a thermoresistance device with a higher sintered density, for stabilizing the resistance value of the thermoresistance device, and for reducing the dispersion in the resistance values with respect to the fluctuations in the

sintering temperature.

  In the heat-resistant portion 13 of the heat-resistance device 1 obtained in this way, the perovskite (M1M2) O3 and Y203 (or A1203) compounds are mixed uniformly via their grain boundaries. A temperature sensor 100 using a heat-resistance device 1 was placed in a high temperature oven and the resistance value and the temperature-resistance coefficient P were measured over the temperature range from room temperature (for example C) at 1000 C, with the rate of change of resistance AR2 during thermal aging at 900 C. Here, this thermal aging will cause the thermoresistor device 1 will be subjected to the effects of a reducing atmosphere inside the cover of metal 2, so the rate mentioned above resistance change AR2 becomes an index for the evaluation of the stability of the resistance value of the thermistor device

1 in this embodiment.

  Here, P has the same meaning as in embodiment 1 above. In addition, the resistance change rate AR2 represents the rate of change of the temperature sensor resistance in a reducing atmosphere as given above, expressed by the formula: AR2 (%) = (Rmaxt / Rt) x100-100 . Here Rt represents the initial resistance value at a stipulated temperature t, (for example, 600 C) and Rmaxt is the maximum resistance value of Rt during aging.

thermal at 900 C.

  As a result, in the temperature range from room temperature to 1000 C, Rt was found to be variable between 50 Q and 100 kΩ, and P is adjustable in the range of 2000-4000K, and AR2 was found as being stable at a level of + (more)

  several% (see Tables 9 and 10).

  Thus, according to this embodiment, by adopting a device structure in which the anti-reducer coating 14 is formed, it is possible to provide a thermoresistor device 1 which has a small value of resistance change rate AR2 and characteristics stable (stability of the resistance value) even if the device itself is subject to

a reducing environment.

  In addition, according to this embodiment, since there is no need to implement the high temperature thermal aging treatment (approximately 900 C) for a long time (approximately 100 hours), it is possible to reduce manufacturing steps and lowering the

sensor costs.

  In addition, by having the heat resisting portion 13 have the above-mentioned mixed sintered body, the sensor has excellent resistance-temperature characteristics, whereby its resistance value is 50Ω to 100kΩ over the starting temperature range. from room temperature to 1000 C, so it is possible to provide a thermistor device that is capable of detecting temperatures over a wide temperature range of the

room temperature at 1000 C.

  In order to achieve the different values of the resistance value (Rt), range and D more reliably, the mole fractions a and b in a (MlM2) O3.bY203 and a (MlM2) O3.bA1203 preferably have the relations 0.05 <a <1.0, 0 <b 0.95 and a + b = 1. In a mixed sintered body, the mole fractions can vary over a wide range so that, by appropriately mixing and sintering the two (M1M2) O3 and Y203 (or A1203), the resistance value and the resistance coefficient temperature can be controlled so

  varied over a wide range of compositions.

  Next, the present invention will be described in more detail by way of Work Examples 1 to 33 and Comparative Examples 1 to 2, but the present invention is by no means limited to these working examples. It should be noted that the working examples 9 to 17 are used to explain the embodiment 4 mentioned above, while the working examples 18 to 23 are used to explain the mode of operation.

  embodiment 5 mentioned above.

  In addition, in working examples 24 to 28, the heat-resistant portion 13 is made of the mixed sintered body (MlM2) O3.Y203 where M1 is Y and M2 is Cr and Mn, thus this is implemented on the mixed sintered body Y (CrMn) O3.Y203. In working examples 29 to 33, the heat-resistant portion 13 is made of the mixed sintered body (MlM2) O3. A1203 where M1 is Y and M2 is Cr and Mn, thus this is carried out on the mixed sintered body Y (CrMn) O3.A1203.

EXAMPLES OF WORK

  (Work Example 1) Work Example 1 is an example of (MlM2) O3 where M1 is Y, M2 is Cr and Mn so that Y (Cro, 5Mno, 5) 03 and A1203 are used to obtain the

  mixed sintered body Y (Cr0.5Mn0.5) O3.A1203.

  Figure 4 shows the manufacturing process

  of the thermistor device of the working example 1.

  This manufacturing process can be broadly divided into a first preparation step from formulation 1 until Y (Cr 0.5Mn 0.5) O 3 is obtained, and a second preparation step from the composition of Y (Cro, 5MnO, 5) O3 thus obtained with Al 2 O 3, etc. (formulation 2) until the device

thermistor is obtained.

During the first preparation step, first Y203, Cr203 and Mn203 each with a purity of 99.9% or more are prepared, and Y203, Cr203 and Mn203 are each weighed so that the molecular ratio of y: Cr: Mn: become 2: 1: 1 in a total weight of 500 g

(formulation 1).

  In order to mix the material thus weighed, a ball mill is prepared by placing 2.5 kg of 15 mm diameter balls and 2.5 kg of mm-diameter beads made of A1203 or Zr203 in a plastic pot ( capacity of 5 liters). The total amount of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 is placed in this jar and 1500 cc of demineralized water is added, followed by mixing at rpm for 6 to 12 hours (mixing step). Here, the mixture after mixing treatment was evaluated using a laser granulometer, and the results indicate that the average

  grain is 1.7 pun (see Table 2).

  The thick mixture of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 obtained after the mixing process was transferred to a porcelain evaporation vessel and dried for 12 hours at 150 ° C. using a hot air dryer.

  to obtain a solid mixture of Y203, Cr203 and Mn203.

  Then, this solid solution was milled in a grinding and milling machine and passed through a 30 # mesh screen for

  obtain a powder mixture of Y203, Cr203 and Mn203.

  During the calcination step, this powder mixture was placed in a 99.3% Al 2 O 3 crucible and calcined for 1 to 2 hours at 1100 to 1300 C in a high temperature oven in air to obtain Y (Cro0,5Mn0,5) 03. Y (Cr0.5Mn0.5) O3 which became a compact type solid in the calcination was coarsely ground in a mixing and grinding machine and passed through a 30 # mesh screen for

get a powder.

  When this Y (Cr0.5Mn05) O3 is used alone as thermistor materials, it shows a low

  resistance and a low coefficient of resistance-

  temperature from 1000 to 4000K. In order to obtain a wide range thermistor material, this Y (Cro, 5MnO, 5) O3 is used with A1203, which is a stabilizing material

  the low resistance of the thermistor.

  During the second preparation step, first Y (Cr0.5Mn0.5) O3 powder and A1203 commercial powder (purity of 99.9% or more, average grain size of 0.6 μm) are weighed to obtain the molar ratio of formulation Y (Cr0.5Mn0.5) 03: A1203 40:60

in a total weight of 500 g.

  Here, if the molar fractions of Y (Cro0.5Mn0.5) O3 and Al2O3 are respectively given as a and b, (a + b = 1), then these values become a = 0.38 and b = 0.62 for correspond to the molar ratio of formulation

given above.

  In addition, SiO 2 and CaCO 3, which provide the liquid phase in the temperature range of 1500 to 1650 ° C during sintering, are used as sintering aids. SiO 2 is added in the amount of 3% by weight and CaCO 3 in the amount of 4.5% by weight of the total weight (500 g) of the Y (Cr 0.5Mno, 5) OO 3 and Al 2 O 3.

  mentioned above (formulation 2).

  Then, during the milling step ("Mixing and grinding" in the Figure), the Y (Cr0.5Mn0.5) O3, Al2O3, SiO2 and CaCO3 mentioned above are placed in a ball mill prepared by placing 2 , 5 kg of 15 mm diameter balls and 2.5 kg of A1203 or Zr203 mm diameter beads in a plastic jar (5 liter capacity). Then 1500 cm3 of demineralised water is added, and mixing is carried out at

rpm for 4 hours.

  In addition, in the grinding process mentioned above, in the solid part of Y (Cro, 5MnO, 5) O 3 and Al 2 O 3 is added a binder of polyvinyl alcohol (PVA) in the amount of 1 g per 100 g of powder mixture of Y (Cr0.5Mn0.5) 03 and Al2O3 while the mixture is mixed and ground. Here, the mixture after mixing treatment was evaluated using a laser granulometer, and the results indicated that the

  average grain size was 2.5 lim (see Table 2).

  The thick ground mixture of Y (Cr0.5MnO5) O3 and Al2O3 obtained after mixing and milling was granulated and dried in a spray dryer for

  obtain a powder mixture of Y (Cr0.5Mn0.5) O3 and Al2O3.

  This powder mixture becomes the raw material of thermistor. Then, during the molding step, this raw thermistor material was used in a mold with an internal diameter of 1.74 mm, in which were inserted conducting wires made of Pt 100 (pure platinum) with dimensions ( outer diameter x length) of 0.3 mm x 10.5 mm. The mixing was carried out at a pressure of about 1000 kgf / cm 2 to obtain a molded thermistor device with a diameter

  1.75 mm outside with attached lead wires.

  During the sintering step, this molded thermistor device was placed on a corrugated layer made of Al 2 O 3 and sintered for 1 to 2 hours at 1400 to 1600 C in air to obtain a thermistor device made of aY (Cr0.5Mn0.5) 03. bA1203 with an outside diameter of

1.60 mm.

  Figure 1 shows the thermistor device 1 thus obtained. The ends of the two parallel conductive wires 11 and 12 are buried in the cylindrical thermistor portion 13 with an outside diameter of 1.60 mm. This thermistor device 1 is assembled into a typical temperature sensor 100 as shown in FIGS. 2 and 3. As shown in FIG. 2, the thermistor device 1 is disposed inside a housing. tubular metal 2 heat resistant. Although not shown, lead wires 11 and 12 are connected to lead wires 31 and 32 of metal pipe 3 which passes through the inside of metal pipe 3. As shown in FIG. The interior of the metal pipe 3 is filled with magnesia powder 33 to insure the insulation of the wires 31 and 32 in the metal pipe 3. This completes the temperature sensor. It should be noted, in this working example and in the other working examples 2 to 8 and in Comparative Examples 1 and 2, the thermistor device and the temperature sensor thus manufactured have the same structure as those shown in FIG.

  Figures 1 to 3, so the explanation is omitted.

  However, the composition of the material for the mixed sintered body is naturally that given in each

example.

  In addition, during the second preparation step mentioned above, the materials are also weighed to give a molar ratio of formulation Y (Cr0.5Mn0.5) O3: Al2O3 of 95: 5 and 5:95, and thermistor are subsequently manufactured by the same

  method and assembled in the temperature sensor.

  Here, the individual devices in which the molar ratio of formulation Y (Cr 0.5Mn 0.5) O 3: Al 2 O 3 is 40:60, 95: 5 and 5:95 are respectively called device number 1, device number 2 and device

number 3.

  A temperature sensor 100 using a thermistor device 1 was placed in a high temperature oven and the temperature characteristics of the resistance value were measured over the temperature range from room temperature (for example, 27 C). at 1000 C in the same manner as in embodiment 1 above. Table 1 represents the results of the evaluation.

  Here, Table 1 represents the results of

  the evaluation of the resistance characteristics

  temperature of the thermistor devices of working examples 2 to 4 given below. As described above, working examples 1 to 4 represent the same mixed sintered body made by different manufacturing methods, as is evident from Table 2, although different methods of manufacture are used, a characteristic Similar temperature resistance is obtained for each mole ratio of a: b formulation. As shown in Table 1, with the thermistor device of this working example 1, when the mole fractions (a + b = 1) of a (M1M2) O3.bAl2O3 are in the ranges of 0.05 <a <1.0 and 0 <b <0.95, the sensor has the required low resistance value of 50 Q to 100 kΩ and the temperature-resistance coefficient P shows the range of 2000 to 4000K, so the resistance value and the temperature-resistance coefficient can be controlled over a wide range. As a result, the sensor is able to detect temperatures over the entire temperature range from room temperature to

1000 C.

  In addition, from the results of the high temperature endurance test (rate of change of resistance AR ') too, it has been found that it is possible to provide a wide range thermistor material which has stable characteristics. the change in the resistance value is small. Therefore, the thermistor device of this example

  Work 1 accomplishes the object of the present invention.

  (Work Example 2) In Work Example 2, as the raw material used to obtain the mixed sintered body Y (Cr0.5Mn0.5) O3.A1203 (M1 = Y, M2 = Cr, Mn), of first Y (Cro0.5Mn0.5) O3 is prepared. Figure 5 shows the method of manufacturing the thermistor device of Work Example 2. This example is a manufacturing method based on the first method of manufacture

  described in Embodiment 2 mentioned above.

  above, but the grinding step in the second preparation step is carried out in a media mixer.

instead of a ball mill.

  As starting materials of Y203, Cr203 and Mn203, materials with a high purity of 99.9% or more are used for each. It should be noted that the average grain size of Y203, Cr203 and Mn203 are

  1.0 μm, 2.0 to 4.0 pumn and 7.0 to 15.0 μm, respectively.

  The average grain size of each of the raw materials are the same as in Work Example 1 mentioned above, and in Work Examples 3 to

  8 and Comparative Examples 1 to 2 shown above.

  In the first preparation step (in Figure 5, from formulation 1 to Y (Cr0.5Mn0.5) O3), first, Y (Cr0.5Mn0.5) O3) is prepared by weighing Y203, Cr203 and Mn203 so that the molar ratio of Y: Cr: Mn: becomes 2: 1: 1 in a weight

500 g total (formulation 1).

  In order to mix the material thus weighed, a ball mill is prepared by placing 2.5 kg of 15 mm diameter balls and 2.5 kg of mm-diameter beads made of Al 2 O 3 or Zr 2 O 3 into a plastic pot ( capacity of 5 liters), 1500 cm3 of demineralized water are added and then the mixing is carried out at 60 rpm for 4 hours (mixing step). Here, mixing after the mixing process was evaluated using a laser granulometer, and the results indicated that the average grain size was 1.7 μm (see Table 2). This is larger than the average grain size of 1.0 pumn for Y203 before mixing. The thick mixture of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 obtained after the mixing process was transferred to a porcelain evaporation vessel and dried for

12 to

  17 hours at 100-150 ° C using a hot air dryer to obtain a solid mixture of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3. Then, this solid mixture was subjected to coarse grinding in a mixing machine and grinding and passed through a 30 # mesh screen for

  obtain a powder mixture of Y203, Cr203 and Mn203.

  During the calcination step, this Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 powder mixture was placed in a 99.3% Al 2 O 3 crucible and calcined for 2 hours at 1100 C in a high temperature oven in an atmospheric pressure environment. (in the air) to obtain Y (Cro, 5Mno, 5) O3. Y (Cr0.5Mn0.5) O3, which became a compact solid during calcination, was coarsely milled in a mixing and grinding machine and passed through a

  30 # mesh sieve to obtain a powder.

  The Y (Cr0.5Mn0.5) O3 mentioned above was used with A1203 as materials for this thermistor. In the second preparation step (in FIG. 5, starting from formulation 2), firstly, Y (Cro, 5Mn0, 5) O3 in powder form (average grain size of 2 to 5 μm) and A1203 (average grain size of 0.6 μm) were weighed to obtain the 40: 60 molar ratio of Y (Cr0.5Mn0.5) 03: Al2O3

total of 2000 g.

  In addition, SiO2 and CaCO3, which provide the liquid phase in the temperature range of 1500 to 1650 C during sintering, are used as a sintering aid. SiO 2 is added in the amount of 3% by weight and CaCO 3 in the amount of 4.5% by weight of the total weight (2000 g) of Y (Cr 0.5 MnO 5) O 3 and Al 2 O 3.

  mentioned above (formulation 2).

  Therefore, the total weight of Y (Cro, 5Mno, 5) O3, Y203, SiO2 and CaCO3 gives 2150 g of

crushed raw materials.

  Then, during the milling step ("Mixing and Grinding" in Fig. 5), in order to carry out a fine grinding of the thermistor raw materials, a "pearl mill" (manufactured in English) is manufactured by Ashizawa Co., Ltd., model RVIV, effective capacity: 1.0 liter, actual capacity 0.5 liter) was used as media mixer. The operating conditions for this bead mill require the use of 3.0 kg of zirconia bales 0.5 mm in diameter as a grinding medium, and 80% of the volume of the mixing chamber to be filled with bales.

of zirconia.

  The operating conditions are adjusted to a peripheral speed of 12 m / s and a rotational speed of 3100 revolutions / minute. It should be noted that 4.5 liters of distilled water was used as a dispersing agent for the 2150 g of raw material to be ground, and the dispersing agent and the binder were added simultaneously, and then the mixture and grinding were carried out for 10 hours. A polyvinyl alcohol (PVA) binder was added in the amount of 1 g per 100 g of the raw material to be ground. The raw material after the mixing treatment was evaluated using a laser granulometer and the results indicated that the average grain size was 0.4 μm (see Table 2). This is smaller than the average grain size of the A1203 before

mixture, which was 0.6 um.

  The crude thick material thus obtained was granulated and dried in a spray drier under conditions of an inlet temperature drying chamber of 200 C and an exit temperature of 120 C. The granules of thermistor material thus obtained were spherical with an average grain size of 30 pim, and these pellets were used to

  mold the thermistor device.

  The molding step was carried out by a mold molding method in which Pt 100 conductive wires with dimensions (outer diameter x length) of 0.3 mm x 10.5 mm were inserted into a male mold, and the pellets were placed in a female mold with an inner diameter

  1.74 mm and the molding was carried out at a pressure.

  of about 1000 kgf / cm2 to obtain a thermistor device molded with attached wire. In the sintering step, this molded thermistor device was placed in a corrugated carrier made of A1203 and sintered for 1 to 2 hours at 1500 to 16000C to obtain a

thermistor device.

  The thermistor device thus obtained and a temperature sensor which incorporates this thermistor device have the same structure as those shown in Figures 1 to 3. In addition, during the second preparation step mentioned above, the materials are also weighed. to give a molar ratio of formulation Y (Cr0.5Mn0.5) O3: A1203 of 95: 5 and 5:95, and thermistor devices were subsequently manufactured by the same procedure and assembled in temperature sensors. Here, the individual devices of this working example 1 in which the molar ratio of formulation Y (Cr0.5Mn0.5) 03: A1203 a: b is 40:60, 95: 5 and: 95 are respectively called device number 4, device number 5, and device number 6. Table 1 shows the results of the evaluation of the temperature-resistance characteristics of the temperature sensors with the thermistor devices of devices number 4 to 6. Thus, this example of work 2 can also providing thermistor devices which have the same meritorious effects as those of Example 1 with respect to the temperature-resistance characteristics of the thermistor device. In addition, the thermistor devices of this Example 2 were subjected to evaluation of the temperature accuracy by the method described in Embodiment 2 above. Here, Table 2 shows the temperature accuracy (C) found using the method described in Embodiment 2 above for the thermistor devices of the examples of

Work 1 to 8 (a: b = 40: 60).

  It should be noted that in Table 2, Y (CrMn) 03 indicates Y (Cr0.5Mn0.5) O3 and Y203. In addition, the average grain size after mixing (pm) indicates the average grain size in the mixtures after the mixing processes during the mixing step of the first preparation step (in this example, the 1.7 upm given above). The average grain size after grinding (pm) indicates the average grain size in the thick paste of the raw material after grinding

At 2775537

  during the grinding stage of the second stage of

  preparation (in this example, the 0.4 μm given

  above). This applies to Work Example 1 and

working examples 3 to 8.

  The thermistor device of device number 4 (a: b = 40: 60) of this working example 2 showed a temperature accuracy of 10 C, which was an excellent value compared to that 23 C of the device thermistor device number 1 (a: b = 40: 60) of Work Example 1 prepared by the

conventional method.

  (Work Example 3) In Work Example 3, the used raw materials Y203, Cr203, Mn203 and CaCO3 are used to obtain the mixed sintered body Y (Cr0.5Mn0.5) O3.A1203 (M1 = Y, M2 = Cr, Mn). Figure 6 shows the method of manufacturing the thermistor device of the example

working 3.

  This example is a combination of the first method of manufacture and the second method of manufacture described in Embodiments 2 and 3 mentioned above. In this example, a media molding mill is used both for the mixing step of the first preparation step (in Figure 6, from Formulation 1 to Y (Cr0.5Mn0.5) O3.A1203) and for both the grinding step of the second preparation step (in Figure 6 from formulation 2). First, materials of Y203, Cr203, Mn203, and CaCO3, each of them with a purity of 99.9% or more, are prepared. In formulation 1, these ingredients are weighed in order to obtain the resistance value and the resistance-temperature coefficients

  desired in the thermistor device.

  In the same way as in Example 1

  above, Y203, Cr203, Mn203 and CaCO3 are weighed so that the molar ratio of Y: Cr: Mn: becomes 2: 1: 1 in

  a total weight of 2000 g (formulation 1).

  Then, a media mixer is used during the mixing step to crush the raw material finely. The media mill-mixer used in this example is the same bead mill as that of Work Example 2 mentioned above, and the

  Mixing conditions are also the same.

  The operating conditions are adjusted to a peripheral speed of 12 m / s and a rotational speed of 3110 revolutions / minute. It should be noted that 4.5 liters of distilled water were used as a dispersing agent for the 2036 of raw material to be molded, and the binder and dispersing agent were added simultaneously, and then the mixture and grinding was carried out for 10 hours. A binder of polyvinyl alcohol (PVA) was added in the amount of 20 g per 2036 g of the raw material before

to be ground.

  The raw material paste after the blending process was evaluated using a laser granulometer and the results indicated that the average grain size was 0.3 μm (see Table 2). This is smaller than the average grain size of Y203 before mixing (1.0 μm) and is also smaller than

0.5 m.

  The thick paste of raw material thus obtained was granulated and dried in a spray dryer under conditions of an inlet temperature drying chamber of 200 C and an outlet temperature of 120 C. The granules of the materials The thermistor thus obtained was spherical with an average grain size of 30 μm, and these powdered raw materials were placed in a crucible of 99.3% Al 2 O 3 and calcined for 1 to 2 hours at 1110 to 1300 C in an oven. high temperature in the air for

  obtain Y (Cr0.5Mn0.5) O3 (calcination step).

  Y (Cr0.5Mn0.5) 03, which became a compact solid during calcination, was coarsely grinded in a mixing and milling machine and passed through a 30 # mesh screen.

  to obtain a powder of Y (Cro, 5Mno, 5) O3.

  Then, in the same way as in working example 1, in formulation 2, the above-mentioned Y (Cro, 5MnO, 5) O 3 and Al 2 O 3 powder (average grain size of 0.6 pun) were been prepared. The molar ratio of formulation of Y (Cr0.5Mn0.5) O3 and Al2O3 was adjusted to 40:60 and the total weight was

2000 g.

  In the same way as in the mixing step above, a bead mill is also used during the milling step. In addition, a dispersing agent, a binder and a mold release agent are added to the precursors made in formulation 2, and the mixture is mixed, milled and granulated. The grinding conditions for this bead mill to be the same as

  in the mixing step above.

  The thick paste of raw material of the thus ground thermistor materials was evaluated using a laser granulometer and the results indicated that the average grain size was 0.3 μm (see Table 2). This is smaller than the average grain size of the A1203 before composing the composition

  in formulation 1 which was 0.6 wm.

  The thick paste of Y (Cr0.5Mn0O5) O3.A1203 thus obtained after grinding was granulated with a spray dryer under the same conditions given in the drying step above to obtain granules of Y (Cr0.5Mn0, 5) O3.A1203. These granules were used

  to mold the thermistor device.

  The molding step was carried out by a mold-molding method, in which Pt 100 conductive wires with dimensions (outer diameter x length) of 0.3 mm x 10.5 mm were inserted into a male mold. the pellets were placed in a female mold with an inner diameter of 1.89 mm and the molding was carried out at a pressure of about 1000 kgf / cm 2 to obtain a thermistor device

  molded with fixed wires.

  This molded thermistor device was placed on a corrugated carrier made of A1203 and sintered for 1 to 2 hours at 1400 to 1600 C to obtain a thermistor device with an outer diameter of 1.60 mm (body

mixed sintered).

  This thermistor device was assembled into a temperature sensor assembly to form a temperature sensor. The thermistor device and the temperature sensor have the same structure as those shown in Figures 1 to 3. In addition, the materials are also weighed to give a molar ratio of formulation Y (Cr0.5Mn0.5) O3: Al2O3 ( a: b) in Formulation 2 of 95: 5 and 5:95, and thermistor devices are subsequently manufactured in the same manner and assembled into temperature sensors. The individual devices of this working example 3 in which the mole ratio of formulation mentioned above a: b is 40:60, 95: 5 and 95 are respectively called device number 7, device number 8, and device number 9. Table 1 shows the results of the evaluation of the temperature-resistance characteristics of these units. Thus, this working example 3 can also provide thermistor devices which have the same meritorious effects as those of the working example 1 with respect to the temperature and resistance value characteristics of the thermistor device. In addition, Table 2 shows the results of the evaluation of the temperature accuracy found by the method described in Embodiment 2 above for the thermistor device of the device number 7 of this working example 3 (FIG. a: b = 40: 60). A thermistor device according to this working example showed a temperature accuracy of 5 C, which was an excellent value compared to that (23 C) of the working example 1 prepared by the conventional method and that

  (10 C) of Work Example 2 above.

  (Work Example 4) In Work Example 4, materials Y (Cro, 5Mn0.5) O3 and Al2O3 are used to obtain the mixed sintered body Y (Cr0.5MnO, 5) 03.A1203 (M1 = Y). , M2 = Cr, Mn). Figure 7 shows the manufacturing process of the

  thermistor device of the working example 4.

  This example of work is an example of the second method of manufacture described in the embodiment 3 mentioned above. In this example, a media mixer is used for the mixing step and the first preparation step (in Figure 7, from Formulation 1 to Y (Cr0.5Mn0.5) 03), while a media mill is used. bead is used for the grinding step of the second preparation step (in Figure 7, from formulation 2). Namely, a ball mill is used in place of a media mixer

  in the grinding step of the working example 3

  above). The first stage of preparation of this example of work is identical to that of the working example 3 above, so its detailed explanation is omitted. It should be noted that in the working example 4 too, the thick paste of the material Crude after the mixing and grinding process during the mixing step was evaluated using a laser granulometer, and the results indicated that the average grain size was 0.3 μm (see Table 2). In addition, from the first stage of the preparation, calcined powder of Y (Cr0.5Mn0.5) O3 a

been obtained.

  In formulation 2, this Y (Cr0.5Mn0.5) 03 (powder) and Al2O3 (average grain size of 0.6μm) were weighed so that the a and b of aY (Cr0.5Mn0.5 ) O3.bAl203 become 40:60 and the weight

total of 2000 g.

  Then, during the grinding step, to mix and grind the weighed Y (Cro, 5MnO, 5) 03 and A1203

  in formulation 2, a ball mill is used.

  The grinding conditions are as follows: 10 kg of 15 mm diameter balls and 10 kg of 20 mm diameter balls made of A1203 are placed in a plastic jar (capacity of 20 liters), 2000 g of the weighed mixture mentioned above and 6000 cc of demineralised water was added and mixing and grinding was carried out at 60 rpm for 6 hours. The thick paste of raw material after grinding processes was evaluated using a laser granulometer, and the results indicated that the average grain size was 1.6 μm (see Table 2). This is more important than the average grain size of A1203 before the composition in formulation 2, which was 0.6 μm. In addition, a dispersing agent, a binder and a mold release agent are added during the milling step and these are

also ground together.

  The thick paste of Y (Cr0 0, 5Mn0 0, 5) 03.A1203 thus obtained after grinding was granulated, molded and sintered in the same manner as in working example 2 to obtain a thermistor device. This thermistor device was assembled into a temperature sensor assembly in the same manner as in Work Example 2 to form a temperature sensor. The thermistor device and the temperature sensor have the same structure as

  those shown in Figures 1 to 3.

  In addition, the materials are also weighed to give a molar ratio of formulation Y (Cr0.5Mn0.5) O3: Al2O3 (a: b) in formulation 2 of 95: 5 and 5:95, and thermistor devices are subsequently manufactured by the same procedure and assembled in temperature sensors. The individual features of this work example 4 in

  which the molar ratio of formulation mentioned above

  a: b is 40:60, 95: 5 and 5:95 are respectively called device number 10, device number 11, and device number 12. Table 1 shows the results of the evaluation of the temperature-resistance value characteristics of these units. Thus, this working example 4 can also provide thermistor devices which have the same meritorious effects as those of the working example 1 with respect to the temperature-value characteristics of

  resistance of the thermistor device.

  In addition, Table 2 shows the results of the evaluation of the temperature accuracy found by the method described in Embodiment 2 above for the thermistor device of device number 10 of this working example 4 ( a: b = 40: 60). A thermistor device according to this working example showed a temperature accuracy of 9 C, which was an excellent value compared to that (23 C) of the working example 1

  prepared by the conventional method.

Table 1

  Mate-.oe composition c-icientResults

  Raw Reaction Number (% mole) Resistance Value (kQ) of Resistance

  Temperature Y (rMn 0.5) 0 3 AR (AR device Y <Cro, 5Mno, 5) O A120 3 room temperature (27 C) 1000 CK (%) 1, 4, 7, 10 40 60 50 0 -07 2580 -5 a

2, t, 'l 95 S 30 O} OS' 2S_10 '-

3, 6, 9, 12 5 95 100 0-1 2710 -5.0

cn --g

Table 2

  Material composition- Medium dimension- Medium dimension- Accuracy of raw rales at the moment of grains no grains grinding temperature after mixing after grinding (C) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (jm) -m; _ _ _ _

Example of. ....

  work 1 Y (CrMn) 03, A1203 1,7 2) 5 + 23 xemP work 2 Y (CrMn) 03, A1203 1/7 0/4 1-10 x span of work 3 Y (CrMn) 03, A1203 0 ; 3 0j3 +5

Example of

  Y (CrMn) 03, A1203 Oy3 1.6 9 Work 4 Y (CrMn) 03, 12, 17 2; 3 Example of Y (CrMn) 03, A1203, Work 1 Y203 7_2_3_ 22 Example of Y (CrMn) ) 03, A1203, 03

1/7 0.3 +9

  6 Y20-3 Example of Y (CrMn) O3 'A1203', 0303 = line 7 Y203 Example of Y (CrMn) 03, A1203, 0.3 1J5 ravail8 Y203 _ _ __ _ _ _ _ _ _ _ _ (Comparative Example 1) As Comparative Example 1, we will describe a temperature sensor which uses a thermistor device having the composition of Y (Cro, 5MnOo, 5) alone without using A1203 or (Y203 + Al203) which

  stabilize the resistance value.

  Y (Cro0.5Mn0.5) 03 is obtained by the same method of

  only in Work Example 1 above.

  Table 3 shows the results of the evaluation of a temperature sensor manufactured using Y (Cr 0.5Mn 0.5) O 3 thus prepared as raw materials. The valuation method of the value characteristics of

  resistance is the same as in work example 1.

  As is clear from Table 3, in the case where A1203 which stabilizes the resistance value is not used, the resistance value in the high temperature region of 1000 C (40 Q) is too much

  low, so the temperature can not be detected.

  In addition, based on the results of the high temperature endurance test (resistance change rate), the resistance change rate AR1 exceeded 20%, so it is not possible to provide a thermistor device which has a characteristic of

  temperature-value of stable resistance.

  Therefore, a thermistor device having the composition of Y (Cr 0.5Mn 0.5) O 3 alone can not be used as a device for the temperature sensor, which is the subject of the present invention. (Comparative Example 2) As Comparative Example 2, we will describe a temperature sensor that uses a thermistor device having the composition of YTiO3 alone without using A1203 or (Y203 + A1203) that stabilize the resistance value. Table 3 shows the

  results of the evaluation of this temperature sensor.

  The valuation method of the value characteristics of

  resistance is the same as in work example 1.

  As is clear from Table 3, in the case of a thermistor device having the composition of YTiO3 alone, the ambient temperature (27 C) is remarkably high, above 10000k, so the temperature can not be detected. In addition, from the results of the high temperature endurance test, the resistance change rate AR 'exceeded 20%, so it is not possible to provide a thermistor device which has a temperature resistance value characteristic.

stable.

Table 3

  Resistance valueCoefficient

  (k) Resistance of Composition of the temperature change .. Temperature o Part of the device- Temperature R R tif room 10600C (K)

xExample- Compara-

  Y (CrosMno5) O3 10 O; 04 2170 -200 xempe Comparative

  ______________________ _____ _______ 100 4 a ___, ___2 ___ -20> 0 t1 f C

  YTiO3> 1000 0; 2 12200 Comparative Example

-40; tif 2 Co o0

At 2775537

  Therefore, a thermistor device having the composition of YTiO3 alone can not be used as a device for the sensor of

  temperature which is the object of the present invention.

  Comparing Work Examples 1 to 4 above, all thermistor devices exhibited good resistance-temperature characteristics, which is the object of the present invention. However, with respect to the temperature accuracy of the sensor, working examples 2 to 4, that is, the manufacturing methods

  presented in the embodiments 2 and 3 above

  above, may be considered superior to

  conventional manufacturing methods.

  That is, in the manufacturing methods taught in Work Examples 2 to 4,

  excellent resistance value characteristics-

  Temperature were obtained through the uniform mixing of the composition by means of fine grinding of the thermistor material, thus reducing the fluctuation in the composition of the mixed sintered body (MlM2) O3.A1203, the dispersion in the value of

  resistance from one sensor to the other can be reduced.

  While working examples 1 to 4 above

  above provide a mixed sintered body of Y (Cr0.5Mn0.5) O3.A1203, the following working examples 5-8 provide a mixed sintered body of Y (Cr0.5Mn0.5) 03.Y203.A1203. It should be noted that with respect to the application of a ball mill or a media mixing mill in the mixing step and in the grinding step, the working examples 5, 6, 7 and 8 correspond to work examples 1, 2, 3 and 4, respectively. (Work Example 5) Figure 8 shows the method of manufacturing the thermistor device of this working example 5. In the same manner as in Work Example 1, the first preparation step is performed (in Figure 8). from formulation 1 to Y (Cr0.5Mno, 5) O3) to obtain a powder of Y (Cro, 5Mn0.5) O3 and then Y203 and Al2O3 are also added and the second preparation step is then carried out (in FIG. 8, from the formulation 2). A ball mill is used in

  two stages of mixing and grinding.

  In formulation 2, so that the thermistor device has the desired resistance value and resistance-temperature coefficient, the Y (Cr0.5Mn0.5) O3, Al203 and Y203 are weighed so that a and b of aY ( Cro, 5Mno, 5) 03.b (A1203 + Y203) have the relation a: b = 40: 60, while the ratio of A1203: Y203

  becomes 50:10 and the total weight is 2000 g.

  The Y (Cr0.5Mn0.5) O3, Al2O3 and Y2O3 thus weighed are subjected to grinding in the same manner as in Work Example 1 (milling step), the resulting raw material thick slurry was evaluated using a laser granulometer and the results indicated that the average grain size was 2.3 pIn (Table 2). This is larger than the average grain size of 1 pin Y203 and also larger than the average grain size of 0.6 pun of A1203

before grinding.

  The thick ground mixture of Y (Cro, 5Mn0, 5) O3, Al2O3 and Y2O3 obtained after grinding was granulated in a spray dryer to obtain a mixture of

  Y powder (Cro, 5Mno, 5) 03, Al 2 O 3 and Y 2 O 3.

  Then, during the molding step, this raw thermistor material was used and Pt 100 lead wires with dimensions (outer diameter x length) of 0.3 mm x 10.5 mm were inserted into a male mold the pellets were placed in a female mold with an inside diameter of 1.89 mm and the molding was carried out at a pressure of approximately 1000 kgf / cm 2 to obtain a molded thermistor device with an outer diameter of 1.89 mm. mm with lead wires attached. In addition, during the sintering step, this molded thermistor device was placed on a corrugated carrier made of Al 2 O 3 and sintered for 1 to 2 hours at 1400 to 1600 C in air to obtain a thermistor device with a diameter. outside of 1.60 mm. This thermistor device was assembled into a temperature sensor assembly in the same manner as in working example 1 to form a temperature sensor. The thermistor device and temperature sensor thus manufactured have the same

  structure than those shown in Figures 1 to 3.

  In addition, during the second preparation step mentioned above, the materials were also weighed to give a molar ratio of aY (Cr0.5MnO.5) 03.b (A1203 + Y203) formulation of a: boa: b = 95: 5 and 5:95 (here the ratio of A1203: Y203 is 50:10), and thermistor devices were subsequently manufactured by the same method and assembled in temperature sensors. The individual devices of this working example in which the molar ratio of the formulation mentioned above a: b is 40:60, 95: 5 and 5:95 are respectively called device number

  13, device number 14 and device number 15.

  The temperature sensors assembled with devices numbered from 13 to 15 were subjected to an evaluation of the resistance-temperature value characteristic in the same manner as in working example 1. Table 4 shows the

results of the evaluation.

  Here, Table 4 also shows the results of the evaluation of the resistance-temperature value characteristics of the thermistor devices of Work Examples 6 to 8 presented below. If the conclusions can therefore be presented, although working examples 5 to 8 have the same mixed sintered body manufactured by different manufacturing methods, as is evident from Table 4, similar temperatures are obtained for each molar ratio of

formulation of a: b.

  As shown in Table 4, with the thermistor device of this working example 5, when the molar fractions (a + b = 1) of aY (Cr0.5Mn0.5) O3.b (A1203 + Y203) found in the ranges of 0.05 to <1.0 and 0 <b <0.95, the sensor has the required low resistance value of 50 Q to 100 kΩ and the temperature-resistance coefficient P is in the range 2000-4000K, thus, the sensor is able to detect temperatures over a wide temperature range from room temperature

up to 1000 C.

  In addition, from the results of the high temperature endurance test (resistance change rate AR1) also, it has been found that it is possible to provide a thermistor material which has stable characteristics where the change in resistance value is small. Therefore, the thermistor device of this example realizes

the subject of the present invention.

  In addition, the thermistor device of device number 13 (a: b = 40: 60 of this working example 5 showed a temperature accuracy of 22 C

(see Table 2).

  (Work Example 6) Figure 9 shows the method of manufacturing the thermistor device of this working example 5. In the same manner as in Work Example 2, a powder of Y (Cr0.5Mn0.5) O3 is obtained, then Y203 and A1203 are also added and finally the second preparation step is carried out (in Figure 9, from formulation 2) using a grinder

medium mixer.

  In formulation 2, so that the thermistor device has the desired resistance value and resistance-temperature coefficient, the Y (Cr0.5Mn0.5) O3, A1203 and Y203 are weighed so that the coefficients a and b of aY (Cr0,5Mn0,5) O3. b (A1203 + Y203) have the relation a: b = 40: 60 (here the ratio of A1203: Y203 becomes 50:10) and that the total weight is

2000 g.

  The Y (Cr0.5Mn0.5) O3, Al2O3 and Y2O3 thus weighed are milled in the same manner as in Work Example 1 (milling step), the resulting raw material thick slurry was evaluated using a laser granulometer, and the results indicated that the average grain size was 0.3 μm (see Table 2). This is smaller than the average grain size of 1 μm Y203 and also smaller than the average grain size of 0.6 μm

of A1203 before grinding.

  The ground pasty mixture of Y (Cr 0.5Mn 0.5) O 3, Al 2 O 3 and Y 2 O 3 obtained after grinding was treated in the same manner as in the working example 5 above, for

  obtain a mixture of granules of powder.

  Then, during the molding step, this mixture of powder granules was used and the molding process and the sintering process were carried out

  in the same way as in the working example 5

  above to obtain a thermistor device with an outer diameter of 1.60 mm. This thermistor device was assembled into a temperature sensor assembly in the same manner as in working example 1 to form a temperature sensor. The thermistor device and the temperature sensor thus manufactured have the same structure as

  those shown in Figures 1 to 3.

  In addition, during the second preparation step mentioned above, the materials are also weighed to give a molar ratio of aY (Cr0.5MnO.5) 03.b (A1203 + Y203) formulation of a: boa: b = 95 : 5 and 5:95 (here the ratio of A1203: Y203 is 50:10), and thermistor devices were subsequently manufactured by the same procedure and assembled into temperature sensors. The individual devices of this working example in which the molar ratio of the formulation mentioned above a: b is 40:60, 95: 5 and 5:95 are respectively called device

  number 16, device number 17 and device number 18.

  The temperature sensors assembled with devices numbered from 16 to 18 were evaluated for the resistance-temperature characteristic in the same way as in Work Example 1. Table 4 shows the results of the 'Evaluation. The thermistor device of this working example 6 is also capable of providing a thermistor device which has meritorious effects similar to those of the working example 5 with respect to the resistance-temperature value characteristics. In addition, the thermistor device of device number 16 (a: b = 40: 60 of this working example 6 showed a temperature accuracy of 9 C (see Table 2), which had an excellent value compared to that of (22). C) of the working example 5

  prepared by the conventional method.

  (Work Example 7) Figure 10 shows the method of manufacturing the thermistor device of this working example 7. In the same manner as in Work Example 3, a powder of Y (Cro, 5Mno, 5) O3 is obtained using a media mixer during the first preparation step (in Figure 10, from formulation 1 to Y (Cro, 5MnO, 5) 03), then Y203 and A1203 are also added, then the Second preparation step is carried out (in Figure 10, from formulation 2) using a media mixer. In formulation 2, so that the thermistor device has the desired resistance value and resistance-temperature coefficient, the Y (CrO 5MnO, 5) O 3, Al 2 O 3 and Y 2 O 3 are weighed so that the coefficients a and b of aY (Cro, 5Mn0,5) 03. b (A1203 + Y203) have the relation a: b = 40: 60, (here, the ratio of

  A1203: Y203 is 50:10) and the total weight is 2000 g.

  The Y (Cr0.5Mn0.5) 03, A1203 and Y203 thus weighed are subjected to grinding in the same manner as in working example 3 (milling step), the resulting raw material paste was evaluated using a laser granulometer, and the results indicated that the average grain size was 0.5 pun (see Table 2). This is smaller than the average grain size of 1 pim of Y203 and then smaller than the average particle size of 0.6 μm of A1203

before mixing.

  The ground pasty mixture of Y (Cro, 5Mn0.5) O3, Al2O3 and Y2O3 obtained after milling was treated in the same manner as in Work Example 5 above for

  obtain a mixture of granules of powder.

  Then, during the molding step, this mixture of powder granules was used and the molding process and the sintering process were carried out.

  in the same way as in Work Example 5

  above to obtain a thermistor device with an outer diameter of 1.60 mm. This thermistor device was assembled into a temperature sensor assembly in the same manner as in working example 1, to form a temperature sensor. The thermistor device and the temperature sensor thus manufactured comprise the same

  structure as shown in Figures 1 to 3.

  In addition, during the second preparation step mentioned above, the materials are also weighed to give a molar ratio of aY (Cr0.5MnO.5) 03.b (A1203 + Y203) formulation of a: boa: b = 95 : 5 and 5:95 (here the ratio of A1203: Y203 is 50:10), and thermistor devices are subsequently manufactured by the same method and assembled in temperature sensors. The individual devices of this working example in which the molar ratio of the formulations mentioned above a: b is 40:60, 95: 5 and 5:95 are respectively called device number

* 19, device number 20 and device number 21.

  The temperature sensors assembled with the devices numbered from 19 to 21 were subjected to an evaluation of the resistance-temperature value characteristic in the same way as in the working example 1. Table 4 shows the results of the Evaluation. The thermistor device of this working example 7 is also capable of providing a thermistor device which has the meritorious effects similar to those of the working example 5 with respect to the resistance-temperature value characteristics. In addition, the thermistor device of device number 16 (a: b = 40: 60 of this work example 6 showed a temperature accuracy of 5 C (see Table 2), which had an excellent value compared to that of (22). C) of the working example 5

  prepared by the conventional method.

  (Work Example 8) Figure 11 shows the method of manufacturing the thermistor device of this working example 8. In the same way as in Work Example 4, a powder of Y (Cr0.5Mno0.5) 03 is obtained during the first preparation stage (in FIG. 11, from formulation 1 to Y (Cr0.5Mn0.5) 03), then Y203 and Al2O3 are also added, and finally the second preparation step is carried out ( in Figure 11, from the formulation 2). A ball mill is used in the mixing stage and a mixing mill

  of medium is used in the grinding step.

  In formulation 2, so that the thermistor device has the desired resistance value and resistance-temperature coefficient, the Y (Cr 0.5Mn 0.5) O 3, Al 2 O 3 and Y 2 O 3 are weighed so that a and b of aY ( Cro, 5Mno, 5) O3.b (Al 2 O 3 Y 2 O 3) have the ratio a: b = 40: 60, (here the ratio of Al 2 O 3: Y 2 O 3 is 50:10)

and the total weight is 2000 g.

  The Y (Cr0.5Mn0.5) 03, A1203 and Y203 thus weighed are subjected to grinding in the same manner as in working example 4 (milling step), the resulting raw material paste was evaluated using a laser granulometer, and the results indicated that the average grain size was 1.5 pure (see Table 2). This is larger than the average grain size of 1 pg of Y203, and also larger than the average pore size of 0.6 μm of the A1203 before

The mixture.

  The ground pasty mixture of Y (Cr 0.5MnO 0.5) 03, Al 2 O 3 and Y 2 O 3 obtained after grinding was treated in the same manner as in the working example 5 above for

  obtain a mixture of granules of powder.

  Then, during the molding step, this mixture of powder granules was used, and the molding process and the sintering process were carried out.

  in the same way as in the working example 5

  above to obtain a thermistor device with an outer diameter of 1.60 mm. This thermistor device was assembled into a temperature sensor assembly in the same manner as in working example 1, to form a temperature sensor. The thermistor device and the temperature sensor thus manufactured comprise the same

  structure as shown in Figures 1 to 3.

  In addition, during the second preparation step mentioned above, the materials were also weighed to give a molar ratio of aY (Cr0.5MnO.5) 03.b (A1203 + Y203) formulation of a: boa: b = 95: 5 and 5:95 (here, the ratio of A1203: Y203 is 50:10), and thermistor devices are subsequently manufactured by the same method and assembled in temperature sensors. The individual devices of this working example in which the molar ratio of the formulations mentioned above a: b is 40:60, 95: 5 and 5:95 are respectively called device number

  22, device number 23 and device number 24.

  Temperature sensors assembled with devices numbered from 22 to 24 were subjected to an evaluation of the resistance-temperature value characteristic in the same manner as in Work Example 1. Table 4 shows the results of the Evaluation. The thermistor device of this working example 7 is also capable of providing a thermistor device which has advantageous effects similar to those of the working example with respect to the value characteristics of the invention.

resistance-temperature.

  In addition, the thermistor device of device number 16 (a: b = 40: 60) of this working example 6 showed a temperature accuracy of 9 C (see Table 2), which had an excellent value compared to that ( 22 C) of the working example 5

  prepared by the conventional method.

Table 4

  Composition of materials (resistance value) Coefficient of resis Crude number (% mole) (kΩ) of resistance of the device Temperature this-temperature change to R1 Y (Cro05Mno, 5) 03 A1203 + Y203 ambient 1io0c ure (K) CDo <27oC )

  13, 16, 19, 22 40 60 50 0.08 2530 -5.0

  14, 17, 20, 23 95 5 30 0.05 2510 -5.0

  , 18, 21, 24 5 95 100 0.17 2500: -5.0

o, n -4

  Comparing work examples 5 to 8 above

  above, all thermistor devices exhibited good temperature-resistance characteristics which is the object of the present invention. However, with respect to the temperature accuracy of the sensor, working examples 6 to 8, or the manufacturing methods presented in Embodiments 2 and 3 above, can be considered superior to manufacturing methods

conventional.

  That is, in the manufacturing methods taught in Work Examples 6 to 8,

  excellent characteristics resistance value-

  Temperature was achieved through the uniform mixing of the composition by means of fine grinding of the thermistor materials, thus reducing the fluctuation in the composition of the mixed sintered body (MlM2) O3.Y203.A1203, the dispersion in the value of

  Sensor resistance in sensor can be reduced.

  (Examples of other modifications of the first aspect) It should be noted that there is no need to say that the wide range thermistor device consisting of a mixed sintered body of Y (CrMn) O3 and Al2O3 (or A1203 and Y203) as in Working Examples 1-8 above, is prepared from Y203 or other components of yttrium, Cr203 or other components of chromium, Mn203 or other manganese components. or A1203 or other aluminum components.

  Moreover, in working examples 1 to 8

  during the first preparation step, the drying before calcination is carried out by hot-air drying, the solid mixture is subjected to a coarse grinding by a mixing and grinding machine, and the calcination is carried out, and in order to To obtain a uniformity of the composition, a binder is added during the mixing step, the granulation is carried out by a spray dryer, and the dried powder mixture is sintered to provide a filtering device.

wide range thermistor.

  In the same way, in order to achieve uniformity of the composition, the sintering in the thermistor device manufacturing step can be performed two or three times to provide a device.

wide range thermistor.

  In working examples 1 to 8 above, the diameter and length of the conductor wires are given as being 0.3 mm in diameter and 0.5 mm in length, their material being given as Pt 100 ( pure platinum), but the shape, diameter and length of the conductive wires can be selected as desired depending on the shape and dimensions of the temperature sensor or the operating environment conditions for the temperature sensor. The material for lead wires need not be Pt 100 (pure platinum) but other high melting metals that have a melting point sufficient to withstand the sintering temperature of the thermistor device and have a conductivity sufficient as lead wires can be used, for example, Pt 80 Ir 20 (80% platinum, 20% iridium)

can be used.

  In addition, in order to prevent the conductive son from becoming disconnected, the section of the conductive son may have a shape other than circular and may be for example rectangular, semicircular or another type of shape. In addition, the surface of the conductive wires may have irregularities, and such conductive wires may be used as wires.

  conductors of the thermistor device.

  In addition, in Work Examples 1 to 8,

  above, the molding method of the thermistor device has been proposed with the insertion of the wires

  conductors, then the implementation of the molding.

  However, it is also possible to open orifices to fix the conductive wires after the thermistor raw material (powder) has been used to mold a cylindrical shape, then to insert the conductive wires and to sinter the assembly to obtain a thermistor device with fixed lead wires. In addition, it is also possible to sinter the cylindrical body above, then subsequently to attach the leads to obtain a

thermistor device.

  In addition, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor devices, to adjust its viscosity or hardness to be suitable for extrusion molding, and thus, using extrusion molding to provide a molded thermistor device with orifices formed to attach conductive wires, and then inserting the conductive wires and sintering the assembly to obtain a thermistor device with fixed lead wires. In addition, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor device, to adjust its viscosity or hardness to be adjusted to the sheet formation and thereby obtain a sheet thermistor shaped sheet with a thickness of 200 Dm. The thickness of five of these laminated sheets together becomes 1 mm, thus a mold can be used to cut a 0.4 mm diameter orifice to fix the lead wires with an outer diameter of 1.8 mm, to obtain a device of thermistor with this form. Then, it is possible to insert the conductive wires and sinter them together to obtain a thermistor device with attached lead wires. It should be noted that in Work Examples 1 to 8 above, it is possible to add an excess of Y 2 O 3 in formulation 1 and to carry out the calcination to form calcine Y (Cro, 5MnO 5 ) O3.Y203 with an excess of Y203, and subsequently add Y203 and A1203 in formulation 2 so that the mixed sintered body has the

desired composition.

  In the above description of the first aspect,

  the thermistor device of this aspect is made of a mixed sintered body of a material expressed by the generic formula a (M1M2) O3. bAl203 or a (MlM2) 03b (A1203 + Y203), having (M1M2) O3 which shows a low resistance value and a low temperature resistance coefficient (for example, 1000 to 4000K) and A1203 (or A1203 and Y203) which is a material which stabilizes the resistance value of the thermistor device. For this reason, by appropriately mixing and sintering the two together, the value

  resistance and resistance coefficient-

  The temperature can be varied over a wide range, so temperatures can be detected over a wide temperature range from room temperature to 1000 C. In addition, from the point of view of accuracy in heating the room temperature at 1000 C also, a thermistor material which has stable characteristics in that the resistance value does not change can be provided

  (working examples 1 to 8 above).

  By means of the method of manufacturing the thermistor device of the first aspect, the uniform mixing of the composition is achieved by means of fine grinding of the thermistor materials so that, by reducing the fluctuation of the composition, the dispersion in the Sensor resistance value in sensor can be reduced, and the temperature accuracy from room temperature to 1000 C can be increased to 10 C (compared to 23 C of conventional manufacturing methods), so a thermistor device that can give a high precision temperature sensor can be provided (working examples 2 to

4 and 6 to 8 above).

  (Work Example 9) Work Example 9 is an example in which the powdered raw material for the thermistor device 1 having a mixed sintered body of 38Y (Cro, 5Mn0.5) O3.62Y203 is synthesized by means of a liquid phase method using metal alkoxides as precursor compounds. Figure 12 shows the manufacturing method of this working example 9. In Figure 12, the portion from the formulation step to the calcination step is equivalent to the first step, and the portion of the granulation and from the drying step to the step of

  Sintering is equivalent to the second step.

  During the first stage, first of all the oxides of triethoxyttrium metals (Y (OC2H5) 3),

  diethoxymanganese (Mn (0C2H5) 2 and tris (2,4-

  pentadiono) chromium (Cr [OC (CH3) CHCOCH3] 3), each with a purity of 99.9% or more, are prepared as the three precursor components which serve as the starting material. Then, during the formulating step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device 1 becomes 38Y (Cr0.5Mn0.5) O3.62Y203. In addition, in order to add Ca as a sintering aid component to the starting material mentioned above, the diethoxycalcium alkoxide (Ca (OC 2 H 5) 2) is weighed in order to

  it comprises 5% by weight of 38Y (Cr0.5Mn0.5) O3.62Y203.

  Then, in the dissolving and mixing step, the starting material and the Ca (OC 2 H 5) 2) thus weighed are dissolved in a solvent mixture of ethanol and isopropyl alcohol 10 times the amount of the starting material. weight, and in the stirring and refluxing step, the reflux is carried out for 10 hours at -90 ° C to obtain the composite metal alkoxide solution which is referenced in the present invention

like the liquid mixture.

  Then, during the heating and polymerization step, the metal salt precipitation agent of demineralized water is added to hydrolyze this composite metal alkoxide solution, and the solution is stirred and mixed. In addition, during the reflux and precipitation step, reflux is carried out for 2 hours at 40-80 ° C to obtain a gelatinous precipitate of metal salts containing the various metal elements of the precursor compounds mentioned above. Then, in the quantity separation and the drying step, this precipitate is separated by filtration and dried, and then during the calcination step, it is calcined to obtain a powdered raw material with the composition 38Y (Cr0.5MnO, 5) O3. 62Y203, the same composition as

of the thermistor device 1.

  Subsequently, during the second step, in the granulation and drying step, to the powdered raw material thus obtained is added a dispersing agent, a binder and a mold release agent, and the mixture is granulated. The granulation is carried out in a spray dryer to obtain

  granules of the composition 38Y (Cr0 5Mn0.5) O3.62Y203.

  Then, during the molding step, these granules are used to form the shape of the thermistor device 1. The molding is carried out by means of a mold-molding method, o Pt 100 conductive wires with dimensions (diameter outer x length) of 0.3 mm x 5 mm are inserted in a male mold, the granules are placed in a female mold with an inner diameter of 1.89 mm and the molding is carried out at a pressure of about 3500 kgf / cm2 to obtain a thermistor device molded with

  lead wires 11 and 12 attached.

  Then, during the sintering step, this molded thermistor device is placed in a corrugated carrier made of Al 2 O 3 and sintered for 1 to 2 hours at 1400-1600 C in air. In this way, the thermistor device 1 is obtained as a mixed sintered body (for example a cylinder 1.6 mm in diameter and 1.2 mm long) with fixed conductor wires 11 and 12. Subsequently, this thermistor device is assembled into a temperature sensor 100 in the

  configuration shown in Figure 2.

  This temperature sensor 100 is placed in a high temperature furnace and the resistance characteristics of the thermistor device, i.e. the resistance-temperature value characteristics.

  (resistance value, resistance coefficient-

  temperature f) and the temperature accuracy A (OC) are measured over the temperature range from room temperature (for example 27 C) to 1000 C of the

  same way as in Work Example 1 above.

  Table 5 shows the results of the evaluation shown with the composition of the thermistor device (composition of the thermistor raw material). It should be noted that Table 5 also shows the results of the evaluation of Work Examples 10 to 17 below. The temperature sensor according to this example shows a precision of

  temperature of 3 C, which is an excellent value.

  In addition, an analytical electron microscope (AEM) was used to examine the crystalline phases of the grains of the crystalline phases which mainly affect the resistance value and an analysis of the crystal grain composition of Y (Cro0.5Mn0.5). 03 was performed. As a result, the crystal grain composition of Y (Cr0.5Mn0.5) O3 was found to be in the range of Y: Cr: Mn = 1: 0.5: 0.5 at Y: Cr: Mn = 1: 0.51: 0.49, thus virtually no conventional dispersion in the composition from the ideal composition was observed, and thus the compositional uniformity at the atomic order or

molecular was found.

  In addition, on the use of a transmission electron microscope (TEM) to observe the thermistor device 1, the various crystal grains (in this example, crystal grains of Y (Cr0.5Mn0.5) O3 and Y203 ) were found to be very fine grains of the order of several nm (nanometers) to several hundred nm which were uniformly

  dispersed / mixed in the composition.

  (Work Example 10) Work Example 10 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cr0.5Mn0.5) O3.62Y203 is obtained as in Work Example 9 but this is carried out by means of a liquid phase method whereby the precursor compounds are mixed in a solution in which the complexing compound of ethylenediaminetetraacetic acid (EDTA) is dissolved. Figure 13 shows the manufacturing process of this

example of work 10.

  Here, in Figure 12, the portion from the formulation step to the calcination step is equivalent to the first step, and the portion from the granulation and drying step to

  the sintering step is equivalent to the second step.

  During the first stage, firstly as nitrates (inorganic metal compounds) yttrium nitrate (Y (NO3) 3.6H20), manganese nitrate (Mn (NO3) 3.6H20) and chromium nitrate (Cr ( NO3) 3.9H20), each with a purity of 99.9% or more are prepared as the three

  precursor compounds which serve as starting material.

  Then, during the formulation step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device 1 becomes 38Y (Cr0.5Mno, 5) O3. 62Y203. In addition, in order to add Ca as a sintering aid component to the above-mentioned starting material, the inorganic calcium nitrate metal compound (Ca (NO 3) 2.4H 2 O) is weighed so that it comprises 5% in

weight of 38Y (Cr0.5Mno, 5) O3.62Y203.

  Then, during the dissolving and mixing step, EDTA in an amount of 3 times by weight that of the starting material is dissolved in a suitable amount of demineralized water. The starting material and the Ca (NO3) 2.4H20 thus weighed are dissolved in the EDTA solution. In this liquid mixture, the various metal ions (Y, Cr, Mn, Ca) react with EDTA to prepare a complex composite metal component in which these metal ions are coordinated and bonded to the metal.

EDTA coordination sites.

  Then, during the heating and polymerization step, to cause a polymerization reaction in this composite metal complex compound and to obtain a precipitate of metal salts, the ethylene glycol metal salt precipitation agent is added in an amount greater than the minimum amount required to cause the polymerization reaction, then the solution is stirred and mixed. Subsequently, this liquid mixture is heated to -200 ° C to advance the polymerization reaction and obtain a polymer formed of the metal complex compound

polymerized composite.

  Then, during the precipitation step, the heating is stopped at the point where the polymerization reaction is advanced sufficiently, and an appropriate amount of water is added to precipitate a gelatinous precipitate of the aforementioned polymer and the metal complex compound. composite (hereinafter referred to as "polymer, etc."). Then this precipitation is separated by filtration and dried, and then calcined to obtain a powdered raw material with the composition 38Y (Cro, 5Mno, 5) O3.62Y203, the same composition as that of the thermistor device 1. Then, during the second step, the treatment is carried out in the same manner as in the working example 9 above, so that the powdered raw material thus obtained is granulated. These granules are used in the molding and sintering steps to obtain the thermistor device 1 with wires

  conductors 11 and 12 fixed as a mixed sintered body.

  Subsequently, this thermistor device 1 assembled into a temperature sensor 100 in the same manner as in the working example 9 above, was subjected to an evaluation of its value characteristics.

  resistance-temperature and temperature accuracy.

  Table 5 shows the results of the evaluation.

  The temperature sensor 100 according to this example has shown a temperature accuracy of 3 C, which is a

excellent value.

  In addition, the analysis of the composition by MEA was carried out as above and it follows that the composition of the crystal grains of Y (Cr 0.5Mn 0.5 O 3) which is the phase of dominance of resistance value, has been found in a range of Y: Cr: Mn = 1: 0.5: 0.5 to Y: Cr: Mn = 1: 0.51: 0.49, thus virtually no conventional dispersion in the composition from the composition ideal has been observed, and thus the uniformity of composition at the atomic and molecular level has been observed. Moreover, it follows from the observation by TEM as above that the various crystal grains of Y (Cr0.5Mno, 5) O3 and Y203 have been observed to be very fine grains of the order of several nm. (nanometers) to several hundred nm which were dispersed / mixed uniformly in the composition. (Work Example 11) Work Example 11 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cro, 5MnO, 5) O3.62Y203 is synthesized at using a liquid phase method using inorganic nitrate compounds as precursor compounds. FIG. 14 represents the manufacturing method of this working example 11. In FIG. 14, the part from the formulation step to the calcination stage is equivalent to the first stage, and the part from from the granulation and the drying step to the sintering step is equivalent to the second step. During the first stage, firstly, the yttrium nitrates, manganese nitrate and chromium nitrate, each with a purity of 99.9% (4N) or more are prepared as the three precursor compounds which serve as the departure. Then, during the formulation step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device 1 becomes 38Y (Cro, 5MnO, 5) 03.62Y203. In addition, in order to add Ca as a sintering aid component to the starting material mentioned above, Ca (OC 2 H 5) 2 is weighed so that it

  comprises 5% by weight of 38Y (Cro, 5MnO, 5) 03.62Y203.

  Then, during the dissolution and mixing step, the starting material and the Ca (NO 3) 2.

  weighed is dissolved in an appropriate amount of water.

  Also, in order to obtain a precipitate of metal salts from the liquid mixture of inorganic metal compounds, the sodium bicarbonate metal salt precipitating agent (Na2CO3) is used. An amount of sodium bicarbonate twice the weight of the starting material is dissolved in a suitable amount of demineralised water to prepare a solution of sodium bicarbonate (solution step

precipitating agent).

  During the stirring and mixing step, to obtain a precipitate of metal salts from the co-precipitation reaction of the mentioned liquid mixture above inorganic metal compounds and sodium bicarbonate solution, the liquid mixture mentioned above inorganic metal compounds is added to the sodium bicarbonate solution and stirred and mixed to obtain a composite carbonate precipitate. Then, this precipitate is separated by filtration, dried and then calcined to obtain a raw material in powder form with the composition 38Y (Cr0.5Mn0.5) O3.62Y203, the same composition as that

of the thermistor device 1.

  Then, during the second step, the treatment is carried out in the same manner as in the working example 9 above, so that the powdered raw material thus obtained is granulated. These granules are used in the molding and sintering steps to obtain the thermistor device 1 with wires

  conductors 11 and 12 fixed as a mixed sintered body.

  Subsequently, this thermistor device 1 assembled into a temperature sensor 100 in the same manner as in the working example 9 above, was subjected to an evaluation of its value characteristics.

  resistance-temperature and temperature accuracy.

  Table 5 shows the results of this evaluation. The temperature sensor 100 according to this example has shown a temperature accuracy of 5 C,

which is an excellent value.

  In addition, the analysis of the composition by AEM was carried out as above, and it follows that the composition of the crystal grains of Y (Cro, 5MnO, 5) O 3 which is the dominant phase of the resistance value, was found in the range of Y: Cr: Mn = 1: 0.48: 0.52 to Y: Cr: Mn = 1: 0.51: 0.49, thus virtually no conventional dispersion in the composition from the composition ideal has been observed, and thus the uniformity of the composition at the atomic or molecular level has been observed. Moreover, it follows from the observation by TEM as above, that the various crystal grains of Y (Cro, 5MnO, 5) 03 and Y203 have been found to be fine grains of the order of several nm to several hundred nm that were dispersed / mixed uniformly in the composition. (Comparative Example 3) Comparative Example 3 is an example of a method of manufacturing the device composition of a 38Y (Cr0.5Mn0.5) thermistor 03.62Y203, the same

  composition as in working examples 9 to 11 below.

  above, but the conventional solid phase method was used. In the solid phase method of this example, the Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 oxides, and CaCO 3 as a sintering aid component were used as raw materials. Mixing and grinding were carried out with a conventional ball mill. Figure 15 shows the manufacturing process of this

Comparative Example 3

  First, Y203, Cr203, Mn203 and CaCO3 each

  with a purity of 99.9% or more are prepared.

  Then, during the formulation step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device 1 becomes 38Y (Cr 0.5Mn 0.5) O3.62Y203. In addition, in order to add Ca as a sintering aid component to the starting material mentioned above, CaCO3 is weighed so that it comprises 5% by weight of 38Y (Cro, 5Mn0.5) 03.62Y203 . The operation of the ball mill during the molding step is carried out as follows. A ball mill is prepared by placing 2.5 kg of 15 mm diameter balls and 2.5 kg of mm diameter beads made of Al 2 O 3 in a plastic jar (20 liter capacity). The weighed Y203, Cr203, Mn203 and CaCO3 are placed in this jar and 6000 cm3 of deionized water are added and the mixing and grinding is carried out at 60 rpm for 6 hours to obtain a paste of raw material. In the calcination process, this pasty mixture of raw material is dried in a spray dryer, and the dry powder thus obtained is placed in a crucible of 99.3% Al 2 O 3 and calcined for 1 to 2 hours at 1100 to 13000 C in a high temperature oven in the air for a calcine

  with a composition of 38Y (Cro, 5Mn0, 5) O3.62Y203.

  During formulation step 2, the desired amount of calcine mentioned above that has become

  a compact type solid in the calcination is weighed.

  Then, during the grinding step (shown as mixing and grinding in Figure 15) a coarse grinding is performed in a mixing and grinding machine.

  grinding and passed through a sieve of 30 mesh.

  In order to grind this again, a ball mill similar to that of the mixing step is used. The grinding conditions of the ball mill were adjusted to the same conditions as the conditions for the above mixing step. In addition, a dispersing agent, a binder and a mold release agent

  were added in this grinding step.

  The raw material paste of the thermistor materials thus obtained was granulated, dried and molded in the same manner as in Working Example 9 above to obtain a molded thermistor device. This molded device is placed on a corrugated adjuster made of A1203 and sintered for 1 to 2 hours at 1500-1600 C in air to obtain a thermistor device. The thermistor device of this example has the same structure as the thermistor device 1 of Figure 1, and the thermistor device is assembled in a temperature sensor having the same structure as the sensor of

temperature 100.

  Subsequently, this thermistor device assembled in a temperature sensor in the same manner as in working example 9 above was subjected to an evaluation of its resistance-temperature value and temperature accuracy characteristics. Table 6 shows the results of the evaluation. Table 6 also shows the results of the evaluation of Comparative Examples 4 to 6. The temperature sensor according to this Comparative Example 3 showed resistance-temperature value characteristics.

  comparable to those of the working examples 9 to 11

  above, which are sintered bodies comprising the same

At 2775537

  composition but its temperature accuracy was

   25 C, which is much worse.

  In addition, composition analysis by AEM was performed on the crystal grain composition of Y (Cr0.5Mn0.5) 03, which is the phase of dominance of the resistance value, in the same manner as in Work Example 9. As a result, the composition of the crystal grains was found in the range of Y: Cr: Mn = 1: 0.4: 0.6 to Y: Cr: Mn = 1: 0, 6: 0.4, compared to the ideal composition Y: Cr: Mn = 1: 0, 5: 0 ,, thus the dispersion in the composition was important and this was determined to be the cause of the degradation

the temperature accuracy.

  Examples of work mentioned above 9 to 11 are examples of a thermistor device 1 made of the mixed sintered body 38Y (Cr0.5Mn0.5) O3.62Y203, while the following working examples 12 to 17 s apply to the liquid phase method of the present invention for thermistor compositions

  other than those of working examples 9 to 11. These

  are examples of the thermistor device 1 made of mixed sintered bodies 40Y (Cr0.5Mno.5) O3.60A1203 in working examples 12 and 13 (Y0.9Cao, 1) (Cro, 75Feo, 2Tio, 05) O03 in working examples 14 and 15 and (Ao10,7Cr0,2Fe0,1) 203.MgO.CaO in the

examples of work 16 and 17.

  (Work Example 12) Work Example 12 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of Y (Cr 0.5Mn 0.5) O 3.60 Al 1 O 3 is synthesized using of a liquid phase method using metal alkoxides as precursor compounds. Figures 16A and 16B show the manufacturing process of this working example 12. In Figures 16A and 16B, the portion from the formulation step (formulation 1 and formulation 2) to the calcination step is equivalent to the first step, and the portion from the granulation and the drying step to the sintering step is equivalent to the second step. Firstly, the alkoxides of triethoxyttrium and diethoxymanganese metals and tris (2,4-pentadiono) chromium, each with a purity of 99.9% or more, are prepared as the three precursor compounds (the chemical formula of each is the same as in Work Example 9 above) that serve as starting materials. Then, during formulation step 1, the three precursor compounds mentioned above are weighed so that the ultimate composition of thermistor device 1 becomes Y (Cr0.5Mn0.5) O3.60A1203. In addition, in order to add Ca as a sintering aid component to the above-mentioned starting material, the calcium diethoxide metal alkoxide Ca (OC 2 H 5) 2) is weighed so that it comprises 5%

  by weight of 40Y (Cro, 5Mn0O, 5) 03.60A1203.

  Then, during the dissolving and mixing step, the starting material and the Ca (OC 2 H 5) 2 thus weighed are dissolved in a solvent mixture of ethanol and isopropyl alcohol 10 times the amount of the starting material. weight and, during the stirring and refluxing step, the reflux is carried out for hours at 40-80 C to obtain a solution of composite metal alkoxide (referenced in the present invention as the liquid mixture). Then, in the first heating and polymerization step, the metal salt precipitating agent of demineralised water is added to hydrolyze this composite metal alkoxide solution and then the solution is stirred and mixed. This liquid mixture is

  called the composite metal polymer liquid.

  Then, in formulation step 2, the precursor compound Al (OC 2 H 5) 3 is weighed so that the ultimate composition of the thermistor device 1 becomes 40Y (Cr 0.5Mn 0.5) O 3. 60 Al 1 O 3. During the second dissolution and mixing, this compound thus weighed is dissolved in a solvent mixture of ethanol and isopropyl alcohol 10 times the amount of the starting material by weight. In the second stage of agitation and

  reflux, the reflux is carried out for 10 hours at 40-

  80 C to obtain an Al alkoxide solution. Then, during the second heating and polymerization step, demineralised water (metal salt precipitating agent) is added in the same manner as in the alkoxide solution. composite metal, then the solution is stirred and mixed. This liquid mixture is called is called polymer liquid A1. In addition, during the reflux and precipitation step, the composite metal polymer liquid mentioned above and the polymer liquid A1 are mixed and this liquid mixture is mixed while the flow is carried out for 2 hours at 40-80 ° C. to obtain a gelatinous precipitate. Then, after this precipitate has been filtered off and dried, it is calcined to obtain a powdered raw material with the composition 40Y (Cr0.5Mn0.5) O3.60A1203, the same

  composition as that of the thermistor device 1.

  Then, during the second step, in the same manner as in Work Example 9 above, the powdered raw material so obtained is subject to granulation and drying, molding and sintering steps to obtain the thermistor device. 1 with lead wires 11 and 12 fixed as a mixed sintered body. Subsequently, this thermistor device 1 assembled in a temperature sensor in the same manner as in the working example 9 above, was subjected to an evaluation of its resistance-temperature value characteristics and its accuracy. temperature. Table 5 shows the results of this evaluation. The temperature sensor 100 according to this example has shown a precision of

  temperature of 2 C, which is an excellent value.

  In addition, the analysis of the composition by AEM was carried out as above, and it follows that the composition of the crystal grains of Y (Cro, 5Mno, 5) O 3 which is the phase of resistance value dominance, has found in the range of Y: Cr: Mn = 1: 0.5: 0.5 to Y: Cr: Mn = 1: 0.51: 0.49, thus virtually no conventional dispersion in the composition from the ideal composition was observed, and the uniformity of composition at the atomic or molecular level was found. Moreover, it results from observation by TEM as above, that the various crystal grains of Y (Cr0.5Mn0.5) O3 and Al2O3 have been found to be very fine grains of the order of several nm. at several hundred nm that were

  dispersed / mixed uniformly in the composition.

  (Work Example 13) Work Example 13 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of Y (Cr0.5Mn0.5) O3.62A1203 is synthesized as in the working example mentioned above 12, but this is done by means of a liquid phase method whereby the precursor compounds are mixed in a solution in which the complexing compound of ethylene diamine tetraacetic acid EDTA is dissolved. Figures 17A and 17B show the process of

  manufacture of this example of work 13.

  Here, in Figures 17A and 17B, the portion from the formulation step (formulation 1 and formulation 2) to the calcination step is equivalent to the first step, and the portion from the granulation and from the drying stage to

  the sintering step is equivalent to the second step.

  First nitrates (inorganic metal compounds), yttrium nitrate, manganese nitrate and chromium nitrate, each with a purity of 99.9% or more, are prepared as the three precursor compounds (the chemical formula of each is the same as in work 10 above) that serve as

starting material.

  Then, during the formulation step 1, the three precursor compounds are weighed so that the ultimate composition of the thermistor device 1 becomes 40Y (Cr0.5Mn0.5) 03.62A1203 In addition, in order to add Ca as a component of sintering aid to the starting material mentioned above, the inorganic metal compound (Ca (NO 3) 2 · 4H 2 O) is weighed in order to

  it comprises 5% by weight of 40Y (Cr0.5Mn0.5) O3.62A1203.

  Then, during the first step of dissolving and mixing, EDTA in an amount of 3 times by weight that of the starting material is dissolved in an appropriate amount of demineralized water. The starting material and the Ca (NO3) 2.4H20 thus weighed is dissolved in the EDTA solution to form the liquid mixture as reference in the present invention. Then, during the first mixing and refluxing step, in this liquid mixture, the various metal ions (Y, Cr, Mn, Ca) react with EDTA to prepare a complex composite metal component in which these metal ions are coordinated. and linked to the sites of

coordination of EDTA.

  Then, during the first heating and polymerization step, to cause a polymerization reaction in this compound metal complex compound and to obtain a metal salt precipitate, the ethylene glycol metal salt precipitation agent is added in an amount greater than the minimum amount required to cause the polymerization reaction, then the solution is stirred and mixed. Subsequently, this liquid mixture is heated to 100-200 C to advance the polymerization reaction and obtain a polymer formed of the polymerized composite metal complex compound. Then, in formulation step 2, Al (NO3) 3.9H20 is weighed so that the ultimate composition of thermistor device 1 becomes Y (Cro, 5MnO, 5) 03.60A1203. In the second dissolving and mixing step, this weighed compound is dissolved and mixed in dissolved EDTA and mixed in demineralized water in an amount of 3 times by weight. During the second stage of agitation and reflux, the refluxing is carried out to react Al (NO3) 3.9H20 with EDTA and prepare a component

Al complex.

  Then, during the second heating and polymerization step, to cause a polymerization reaction in this Al complex compound and to obtain a metal salt precipitate, the ethylene glycol metal salt precipitation agent is added to excess to cause the polymerization reaction, then the solution is stirred and mixed. Subsequently, this liquid mixture is heated to 100-200 C to advance the polymerization reaction. This mixture

  liquid is called the polymer liquid Al.

  Then, during the mixing and precipitation step, the aforementioned composite metal polymer liquid and the polymer liquid Al are mixed, and while this liquid mixture is agitated, the heating is stopped at the point where the reaction of The polymerization has progressed sufficiently, and an appropriate amount of demineralised water (metal salt precipitation agent) is added to precipitate the polymer, etc. as a gelatinous precipitate of metal salts. This precipitate is then separated by filtration and dried, and then calcined to obtain a raw material in powder form with the composition 38Y (Cro, 5Mn0.5) O3.62Y203, the same composition as that of the

thermistor 1.

  Then, during the second step, in the same manner as in Work Example 9 above, the powdered raw material thus obtained is subjected to granulation and drying, molding and sintering steps to obtain the thermistor device. 1 with lead wires 11 and 12 fixed as a mixed sintered body. Subsequently, this thermistor device 1 assembled in a temperature sensor in the same manner as in the working example 9 above, was subjected to an evaluation of its resistance-temperature value characteristics and its accuracy. temperature. Table 5 shows the results of the evaluation. The temperature sensor 100 according to this example has shown a temperature accuracy

  of 2 C, which is an excellent value.

  Moreover, the analysis of the composition by AEM was carried out as above, and the result is that the composition of the crystal grains of Y (Cr 0.5Mn 0.5) 03, which is the dominant phase of the resistance value, was found in the range of Y: Cr: Mn = 1: 0.5: 0.5 at Y: Cr: Mn = 1: 0.51: 0.49, thus virtually no conventional dispersion in the composition from the ideal composition was observed, and thus the uniformity of the composition of the atomic and molecular order was observed. Moreover, it follows from the observations TEM above, that the various crystal grains of Y (Cro0.5Mn0.5) O3 and Al2O3 have been found to be very fine grains of the order of several nm to several hundreds of grains. nm that were scattered /

  mixed uniformly in the composition.

  (Comparative Example 4) Comparative Example 4 is an example of a method of manufacturing the composition of a 40Y (Cr0.5Mn0.5) O3.60A1203 thermistor device, the same composition as in the working examples. 12 and 13 above, but the conventional solid phase method is used. In the solid phase method of this example, the Y 2 O 3, Cr 2 O 3, Mn 2 O 3, and Al 2 O 3 oxides and CaCO 3 as a sintering aid component were used as raw materials. Mixing and grinding were carried out with a conventional ball mill. Figure 18 shows the process of

  manufacture of comparative example 4.

  First, Y203, Cr203, Mn2O3, Al2O3 and CaCO3 each with a purity of 99.9% or more are prepared. During formulation step 1, the Y203, Cr203, and Mn203 are weighed so that the calcine composition after the calcination step becomes Y (Cro, 5Mno0, 5) O3. In addition, in order to add Ca as a sintering aid component to the above-mentioned starting material, CaCO3 is weighed so that it comprises 5% by weight of 40Y (Cr0.5Mn0.5) O3.60A1203 . Then,

  in the same way as in Comparative Example 3

  above, the mixing step and the calcination step were performed to obtain a calcine with the

Y composition (Cro, 5Mno, 5) 03.

  During formulation step 2, A1203 is weighed so that the composition becomes Y (Cr0.5Mn0.5) O3.60A1203. Then, during the grinding step, the calcine and the Al 2 O 3 thus weighed are mixed and the grinding is carried out with a ball mill with the grinding conditions adjusted to the same conditions as those of Comparative Example 3. In addition, a dispersant, a binder and a mold release agent were added during this step

  grinding as in Comparative Example 3.

  In the same way as in Comparative Example 3 above, the viscous paste of raw material thus obtained is granulated, dried, molded and sintered. The resulting thermistor device was assembled in a temperature sensor and its temperature-resistance value characteristics and temperature accuracy were evaluated. Table 6 shows the results of this evaluation. The temperature sensor according to this comparative example 4 showed temperature-resistance value characteristics comparable to those of working examples 12 and 13 above, which are sintered bodies having the same composition, but its temperature accuracy was

 23 C, which is worse.

  In addition, the composition analysis AEM was performed on the composition of crystal grains of Y (Cr0.5Mn0.5) 03, which is the phase of dominance of the resistance value, in the same way as in the Work Example 9. As a result, the composition of Y (Cr0.5Mn0.5) O3 crystal grains was found in the range of Y: Cr: Mn = 1: O, 4: 0.6 at Y: Cr Mn = 1: 0.6: 0.4, compared to the ideal composition of Y: Cr: Mn = 1: 0.5: 0.5, so that the dispersion in the composition is important, and this has been determined as the cause

  degradation of the temperature accuracy.

  (Work Example 14) Work Example 14 is an example in which the powdered raw material for a thermistor device 1 consisting of a mixed sintered body of the composition (Y0o, 9CaO1) (Cro, 75Fe0.2Tio0.05 ) 03 is synthesized using a liquid phase method using organometallic compounds such as the compounds

  precursors as in Example 9 mentioned above.

  Figure 19 shows the manufacturing process of this working example 14. In Figure 19, the portion from the formulation step to the calcination step is equivalent to the first step, and the part from from the granulation and the drying step to the sintering step is equivalent to the

second step.

  Firstly, triethoxyttrium (Y (OC 2 H 5) 3), diethoxymanganese (Mn (OC 2 H 5) 2 and tris (2,4-pentadiono) chromium (Cr [OC (CH 3) CHCOCH 3] 3 metal alkoxides, triethoxy iron (Fe (OC 2 H 5) 3) and tetraethoxytitanium (Ti (OC 2 H 5) 3) each with a purity of 99.9% or more are prepared as the five precursor components which serve as the starting material. formulation, the five precursor compounds mentioned above are weighed so that the ultimate composition of the

  thermistor becomes (Y0o, 9Cao, 1) (Cro, 75Feo, 2Tio, 05) 03.

  Then, during the dissolving and mixing step, the thus weighed starting material is dissolved and mixed in a solvent mixture of ethanol and isopropyl alcohol 10 times the amount of the starting material by weight. During the stirring and refluxing step, the reflux is carried out for 10 hours at 40-60 ° C to obtain a composite metal alkoxide solution (referenced in the present invention as the liquid mixture). Then, during the heating and polymerization step, the metal salt precipitating agent of demineralized water is added to hydrolyze this composite metal alkoxide solution, and the solution is stirred and mixed. In addition, during the reflux and precipitation step, the reflux is carried out for 2 to 4 hours at 40-60 ° C to obtain a gelatinous precipitate of a composite of metal salts. Then, after this precipitate has been filtered off and dried, it is calcined to obtain a powdered raw material with the composition (Y09Ca0.1) (Cr0.75Fe0.2Ti0.05) 03, the same composition as that of

thermistor device 1.

  Then, during the second step, in the same manner as in Work Example 9 above, the powdered raw material thus obtained is subjected to granulation and drying, molding and sintering steps to obtain the thermistor device. with lead wires 11 and 12 fixed as a mixed sintered body. Subsequently, this thermistor device 1 assembled in a temperature sensor 10 in the same manner as in the working example 9 above, was subjected to an evaluation of its resistance-temperature value and accuracy characteristics. temperature + A. Table 5 shows the results of the evaluation. The temperature sensor 100 according to this example has shown a precision of

  temperature of 5 C, which is an excellent value.

  In addition, the composition analysis by AEM was performed on the composition of the crystal grains of (Yo, 9Cao, 1) (Cro, 75Fe0, 2Ti0.05) O3, which is the resistance value dominating phase, in the same way as above. As a result, the composition of the crystal grains was found to be in the range of Y: Ca: Cr: Fe: Ti = 1: 0.9: 0, 1: 0.75: 0.2: 0.05 at Y: Ca: Cr: Fe: Ti = 0.9: 0.1: 0.74: 0.21: 0.05, so virtually no conventional dispersion in the composition from the ideal composition was observed, and so the uniformity of the composition of the atomic order and

molecular was observed.

  Moreover, it follows from the TEM observation as above that the various crystal grains of (Y0.9Cao, 1) (Cr0.75Fe0.2Ti0.05) 03 have been observed to be very fine grains. order of several nm to several hundred μm which were dispersed / mixed uniformly in the composition. (Work Example 15) Work Example 15 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of the composition (Yo, gCao,) (Cro, 75Feo, 2Tio, 05) O3 is synthesized as in the working example mentioned above 10, but this is done by means of a liquid phase method whereby the precursor compounds are mixed in a solution in which the complexing compound EDTA is dissolved . Figure 20 shows the process of

  manufacture of this example of work 15.

  Here, in Figure 20, the portion from the formulation step to the calcination step is equivalent to the first step, and the portion from the granulation and drying step to the sintering step is equivalent to the second step. First, nitrates (inorganic metal compounds), yttrium nitrate (Y (NO3) 3.6H20), calcium nitrate (Ca (NO3) 2.4H2O), chromium nitrate (Cr (NO3) 3.9 H20), iron nitrate (Fe (NO3) 3.9H2O and titanium oxynitrate (5TiO2.N2O5.6H2O), each with a purity of 99.9% or more are prepared as the five

  precursor compounds which serve as starting material.

  Then, during the formulation step, the five precursor compounds mentioned above are weighed so that the ultimate composition of the

  thermistor 1 becomes (Yo, 9Cao, 1) (Cro75Feo, 2Tio05) 03.

  Then, during the first step of dissolving and mixing, EDTA in an amount of 4 times by weight that of the starting material is dissolved in an appropriate amount of demineralized water. The thus weighed starting material is dissolved in this EDTA solution to form the liquid mixture as referenced in the present invention. Then, during the mixing and refluxing step, in this liquid mixture, the various metal ions (Y, Ca, Cr, Fe, Ti) react with EDTA to prepare a composite metal complex compound in which these metal ions are coordinated and linked

  at the EDTA coordination sites.

  Then, in the heating and polymerization step, to cause a polymerization reaction in this composite metal complex compound and to obtain a precipitate of metal salts, the ethylene glycol metal salt precipitating agent is added in excess of the minimum amount necessary to cause the polymerization reaction, then the solution is stirred and mixed. Subsequently, this liquid mixture is heated to 80-120 ° C to advance the polymerization reaction. Then, during the precipitation step, the heating is stopped at the point where the polymerization reaction has sufficiently advanced, and a suitable amount of demineralised water (metal salt precipitating agent) is added to precipitate the polymer, etc.) like a precipitate

gelatinous salts of metals.

  Then, this precipitation is separated by filtration and dried, then it is calcined to obtain a raw material in powder with the composition (Yo, 9Cao, 1) (Cro, 75Fe0, 2Ti0, 05) 03, the same composition as

  that of the thermistor device 1.

  Then, during the second step, in the same manner as in working example 9 above, the powdered raw material thus obtained is subjected to granulation and drying, molding and sintering steps to obtain the thermistor device. 1 with lead wires 11 and 12 fixed as a mixed sintered body. Subsequently, this thermistor device 1 assembled into a temperature sensor 100

  in the same way as in Work Example 9

  above, has been subjected to an evaluation of its resistance-temperature value characteristics and temperature accuracy. Table 5 shows the results of the evaluation. The temperature sensor 100 according to this example has shown a temperature accuracy

  5 C, which is an excellent value.

  In addition, the results of the AEM composition analysis and the TEM observation were

  similar to those in Work Example 14

  above, in that the crystal grains of Y0.9Cao, 1) (Cro, 75Fe0, 2Ti0.05) 03, which is the dominant phase of the resistance value, have been found to be very fine grains of the order from several nm to several hundreds of nm which are dispersed / mixed in a

uniform in the composition.

  (Comparative Example 5) Comparative Example 5 is an example of a method of manufacturing the thermistor device composition of Yo, 9Cao, 1) (Cr0.75Fe0.2Ti0.05) O3, the same composition as in Work Examples 14 and 15 above, but the conventional solid phase method is used. In the solid phase method of this example, the Y 2 O 3, Cr 2 O 3, Fe 2 O 3, TiO 2 and CaCO 3 oxides are used as raw materials. Mixing and milling are done with a conventional ball mill. Figure 21 shows the process

  of manufacture of Comparative Example 5.

  First, Y203, Cr 2 O 3, Fe 2 O 3, TiO 2 and CaCO 3 each with a purity of 99.9% or more are prepared. In the formulation step, the materials are weighed so that the calcine composition after the calcination step becomes Y0.9Cao, 1) (Cro, 75Fe0, 2Ti05) 03. Then, in the same way

At 2775537

  that in comparative example 3 above, the mixing step and the calcination step are carried out in order to

get a calcine.

  Then, in the same manner as in Comparative Example 3, the calcine thus obtained is subjected to mixing and grinding with a ball mill, and to the granulation, molding and sintering steps to obtain a thermistor device. The thermistor device thus obtained was assembled in a temperature sensor and its resistance-temperature value characteristics and temperature accuracy were evaluated. Table 6 represents the result of the evaluation. The temperature sensor according to this Comparative Example 5 showed resistance-temperature characteristics comparable to those of Working Examples 14 and 15 above, which are sintered bodies having the same composition, but its temperature accuracy was 30 C, which is

not a good value.

  In addition, AEM composition analysis was performed on the crystal grain composition of Yo0.9Ca0.1 (Cr0.75Fe0.2Ti0.05) O3, which is the phase of dominance of the resistance value, the same way as above. As a result, the composition was in the range Y: Ca: Cr: Fe: Ti = 0.85: 0.15: 0.70: 0.15: 0.15 to Y: Ca: Cr: Fe: Ti = 0.93: 0.07: 0.78: 0.21: 0.01 compared to the ideal composition of Y: Ca: Cr: Fe: Ti = 0.9: 0.1: 0.75: 0, 2: 0.05 thus the dispersion in the composition was important, and this was determined to be the cause of the degradation

the temperature accuracy.

  (Work Example 16) Work Example 16 is an example in which the powdered raw material for a thermistor device consisting of a mixed sintered body of the composition (Ao10.7Cr0.2Fe0o, 1) 203.MgO.CaO is synthesized during the first step using a liquid phase method using organometallic compounds as precursor compounds in the same manner as in working example 9 above. Figure 22 shows the manufacturing method of this working example 16. In Figure 22, the portion from the formulation step to the calcination step is equivalent to the first step, and the portion from from the granulation and the drying step to the sintering step is equivalent to the second step. First during the first step, triethoxyaluminum metal alkoxides (Al (OC2H5) 3), tris (2,4-pentadiono) chromium (Cr (OC (CH3) CHCOCH3] 3) and iron triethoxy ( Fe (OC2H5) 3) each with a purity of 99.9% or more are prepared as the three precursor compounds which serve as the starting material. Then, during the formulation step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device

  become (Ao10.7Cr0.2Fe0.1) 203.MgO.CaO.

  In addition, in order to add the raw materials of Ca Mg as sintering aid components in the form of organometallic compounds similar to those for the above mentioned diethoxymagnesium (Mg (OC 2 H 5) 2) starting material and diethoxycalcium (Ca (OC2H5) 2) are weighed so that each has 2%

* weight of (Ao10.7Cr0o2Fe0.1) 203.

  Then, during the dissolving and mixing step, the thus weighed starting material is dissolved and mixed in a solvent mixture of ethanol and isopropyl alcohol 10 times the amount of the starting material by weight. During the stirring and refluxing step, the reflux is carried out for 10 hours at 40-80 ° C to obtain a composite metal alkoxide solution (referenced in the present invention as the liquid mixture). Then, during the heating and polymerization step, the metal salt precipitating agent of demineralised water is added to hydrolyze this composite metal alkoxide solution, and the solution is stirred and mixed. In addition, during the reflux and precipitation step, the reflux is carried out for 2 to 4 hours at 40-60 ° C to obtain a gelatinous precipitate of a composite of metal salts. Then, after this precipitate has been filtered off and dried, it is calcined to obtain a raw material in powder form with the composition (A10.7Cr0.2Fe0.1) 203.MgO.CaO, the same composition as that of the

thermistor 1.

  Then, during the second step, in the same manner as in Work Example 9 above, the powdered raw material thus obtained is subjected to granulation and drying, molding and sintering steps to obtain the thermistor device. 1 with lead wires 11 and 12 fixed as a mixed sintered body. Subsequently, this thermistor device 1 assembled in a temperature sensor in the same manner as in the working example 9 above, was subjected to an evaluation of its resistance-temperature value characteristics and its accuracy. temperature. Table 5 shows the results of the evaluation. The temperature sensor 100 according to this example has shown a temperature accuracy

  5 C, which is an excellent value.

  In addition, composition analysis by AEM was performed on the crystal grain composition of (Ao10,7Cro, 2Fe0, 1) 203, which is the dominant phase of

  resistance value, in the same way as above.

  As a result, the composition of the crystal grains was found to be in the range of Al: Cr: Fe = 0.7: 0.2: 0.1 to Al: Cr: Fe = 0.69: 0 , 21: 0.1, so that virtually no conventional dispersion in the composition from the ideal composition was observed, and thus the uniformity of atomic and molecular order composition was observed. Moreover, it follows from the observation by TEM as above that the various crystal grains of (Alo, 7Co, 2Fe0, 1) 203, MgO and CaO have been found to be very fine grains of the order of several nm to

several hundred nm.

  (Work Example 17) Work Example 17 is an example in which the powdered raw material for the thermistor device 1 consisting of a composite sintered body (Alo, 7Cro, 2Feo, 1) 203.MgO.CaO is synthesized as in the working example mentioned above 14, but this is done by means of a liquid phase method in which the precursor compounds are mixed in a solution in which the complexing compound EDTA is dissolved. Figure 23 shows the

  manufacturing process of this working example 17.

  In Figure 23, the portion from the formulation step to the calcination step is equivalent to the first step, and the portion from the granulation and drying step to

  the sintering step is equivalent to the second step.

  First nitrates (inorganic metal compounds), aluminum nitrate, (Al (NO3) 3.9H2O), chromium nitrate (Cr (NO3) 3.9H2O) and iron nitrate (Fe (NO3) 3.9H2O) , each with a purity of 99.9% or more are prepared as the three compounds

  precursors that serve as starting material.

  Then, during the formulation step, the three precursor compounds mentioned above are weighed so that the ultimate composition of the thermistor device 1 becomes (A10.7Cr0.2Fe0.1) 203. MgO.CaO. In addition, in order to add the raw materials of Mg and Ca as sintering aid components in the form of inorganic metal compounds similar to those of the starting material mentioned above, magnesium nitrate (Mg (NO3) 2.6 H2O) and calcium nitrate (Ca (NO3) 2.4H2O) are weighed so that they comprise 2% by weight and 2% by weight, respectively of

(A10,7Cr0,2Fe0,1) 203.MgO.CaO.

  Then, during the dissolving and mixing step, the EDTA in an amount of 3 times by weight that of the starting material is dissolved in an appropriate amount of demineralized water. The above-mentioned starting material is dissolved in the EDTA solution to form the liquid mixture as referenced in the present invention. Then, during the mixing and refluxing step, in this liquid mixture, the various metal ions (Al, Cr, Fe, Mg, Ca) react with EDTA to prepare a complex composite metal compound in which these ions Metallic are

  coordinated and linked to EDTA coordination sites.

  Then, during the heating and polymerization step, to cause a polymerization reaction in this composite metal complex compound and to obtain a precipitate of metal salts, the ethylene glycol metal salt precipitating agent is added in excess of the minimum amount necessary to cause the polymerization reaction, then the solution is stirred and mixed. Subsequently, this liquid mixture is heated to 80-120 ° C to advance the polymerization reaction. Then, during the precipitation step, the heating is stopped at the point where the polymerization reaction has advanced sufficiently, and an appropriate amount of demineralized water (metal salt precipitating agent) is added to precipitate the polymer, etc. . like a

  gelatinous precipitate of metal salt.

  This precipitate is then separated by filtration and dried, and then calcined to obtain a raw material in powder form with the composition (Alo, 7Co, 2Fe, 1) 203 MgO.CaO, the same composition as that of the

thermistor 1.

  Then, during the second step, in the same manner as in Work Example 9 above, the powdered raw material thus obtained is subjected to granulation and drying, molding and sintering steps to obtain the thermistor device. 1 with the lead wires 11 and 12 attached as a mixed sintered body. Subsequently, this thermistor device 1 assembled into a temperature sensor 100

  in the same way as in Work Example 9

  above, has been subjected to an evaluation of its resistance-temperature value characteristics and temperature accuracy. Table 5 shows the results of the evaluation. The temperature sensor according to this example has shown a precision of

  temperature of 5 C, which is an excellent value.

  In addition, the results of the AEM composition analysis and the TEM observations were

  similar to those in Work Example 14

  above, in that the crystal grains of (Ao10.7Cr0.2Fe0.1) 203 which is the dominant phase of the resistance value, have found themselves to have a uniform composition of the molecular and atomic order. In addition, the crystal grains of (Ao10.7Cr0.2Fe0.1) 203 were found to be very fine crystal grains of the order

  from several nm to several hundreds of nm.

  (Comparative Example 6) Comparative Example 6 is an example of a method for manufacturing the composition of the thermistor device of (Alo, 7Cr0.2Fe0.1) 203.MgO.CaO, the same composition as in the working examples. 16 and 17 above, but the conventional solid phase method is used. In the solid phase method of this example, the Y 2 O 3, Cr 2 O 3, Fe 2 O 3, MgO and CaCO 3 oxides are used as the raw materials. Mixing and milling are done with a conventional ball mill. Figure 25 shows the process

  of the comparative example 6.

  First, Al 2 O 3, Cr 2 O 3, Fe 2 O 3, MgO and CaCO 3 each with a purity of 99.9% or more are prepared. During the formulation step, the materials are weighed so that the calcine composition after the calcination step becomes (Alo0.7Cro, 2FeO01) 203 15.MgO.CaO. Then, in the same way as in Comparative Example 3 above, the mixing step and the step of

  calcination are carried out to obtain a calcine.

  Then, in the same manner as in Comparative Example 3, the calcine thus obtained is subjected to mixing and grinding with a ball mill, and granulation, molding and sintering steps to obtain a thermistor device. The resulting thermistor device was assembled into a temperature sensor and its resistance-temperature value characteristics and temperature accuracy were evaluated. Table 6 shows the results of the evaluation. The temperature sensor according to this comparative example 6 showed resistance-temperature value characteristics comparable to those of working examples 16 and 17 above, which are sintered bodies having the same composition, but its temperature accuracy was 30 C, which is

less good.

  In addition, the analysis of the composition by AEM was performed on the composition of the crystal grains of (Alo, 7Cro, 2Feo, 1) 203, which is the dominant phase.

  resistance value, in the same way as above.

  As a result, the composition was in the range of Al: Cr: Fe = 0.78: 0.17: 0.05 to Al: Cr: Fe = 0.65: 0.23: 0.12 compared at the ideal composition of Al: Cr: Fe = 0.7: 0.2: 0.1, thus the dispersion in the composition was important, and this was determined to be the cause of the degradation of the accuracy

temperature.

Table 5

  Raw material composition Resistance value Coefficient Thermistor temperature (resistance knIr of temperature accuracy temperature (A) (C) ambient temperature 1000 ° C: working temperature 9 38Y (CrosMno, 5) 03'62Y203 50,007 2580 3 Example 38Y (Cro, 5Mno05) 03.62Y203 50 O7 2580 +3 Example e 500j07 2580 3 'work 10 3 _o (3 Example of 38Y (Cr0.5Mno 5) 0 3.62Y203 50 007 2580 +5 work 1] Example from 40Y (Cro / sMno5) 03.60Al20O3 50 0; 07 2580 +2

work12 11 -

  Example of 40Y Mn (C r a05) 03 e2Too2 S0 007 2580 2 work 13 Example of (YOCao1) (Cro75Feo2Tio) O3 300 0 1 3140 +5

ravail 1 I _-

  Example of - (Y0; 9Ca 01) (Cro075Feo; 2Ti0; 0) O | 300 0) 1 3140 +5 work 15_ .. 7 Example of (Alo, 7Cro2Fe021) 203.MgO-Cao 00 0> 3 2980 j work 16 Example of (A1O, 7Cr 0 2Fe) 203MgOCaO 600 0 | 3 2980 II

work 1 7 O; 2Feo.

(n 5 -4

Table 6

  Resistance value Coefficient Temperature Material composition (k _) _ Resistance of raw thermistor thermoregulated to temperature 27 1000 C ture (C)

(27 C). (K),

Exemp the Comparative 3

: Example

  Example 4OY (CroeMn o5) O3 -6O203 50 0 07 2580 - F2 30! Comparative 4 _ ___ 5 __ 28_ __

ExempleCaj

  EXAMPLE 5 (Comparative Example 5) Comparative Example 6 (ALC (Cr eO 2 TiOp) [5] Work Example 18 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cr0.5Mn0.5) O03.62Y203 is obtained, but this is done by means of a liquid phase method in which the complexing agent citric acid is used as the composite complexing compounds, and

  ethylene glycol is used as the polymerizing agent.

  FIG. 18 shows the manufacturing method of this working example 18. In FIG. 18, the part from the formulation step to the calcination stage is equivalent to the first stage, and the part from from the granulation and the drying step to the sintering step is equivalent to the

second step.

  During the first stage, firstly nitrates (inorganic metal compounds), yttrium nitrate (Y (NO3) 3.6H20), manganese nitrate (Mn (NO3) 3.6H20) and chromium nitrate (Cr (NO3) 3.9 H20), each with a purity of 99.9% or more, are prepared as the three precursor compounds that serve as

starting material.

  Then, during the formulation step, the above three precursor compounds are weighed so that the ultimate composition of the thermistor device 1 becomes 38Y (Cr0.5Mn0.5) O3. 62Y203. In addition, in order to add Ca as a sintering aid component to the above-mentioned starting material, the inorganic metal compound calcium nitrate (Ca (NO 3) 2.4H 2 O is weighed to 5% by weight. weight

of 38Y (Cr0.5Mn0.5) 03.62Y203.

  Then, in the dissolving and mixing step, first 60 g of citric acid is dissolved in 2 liters of deionized water to obtain a citric acid solution in which, if e is the number of moles of citric acid and f is the total number of moles of all constituent elements Y, Cr and Mn of the composition, then the concentration of citric acid is e / f = 1 (this is defined as once per mole) . Then, during the stirring and refluxing stage, the starting material above and calcium nitrate are added to this citric acid solution, where the various metal ions (Y, Cr, Mn, Ca) are added. react with citric acid to form a complex composite metal composite in which these metal ions are coordinated and bonded to the citric acid coordination sites. Then, during the heating and polymerization step, to cause a polymerization reaction in this composite metal complex compound and to obtain a metal salt precipitate, ml of the ethylene glycol polymerizing agent is added. Subsequently, this liquid mixture is heated to 80-2000C to advance the polymerization reaction. Then, the heating is stopped to the point when the polymerization reaction has sufficiently

  advanced, to obtain a viscous gelatinous liquid.

  Then, during the drying step, this polymer is placed in a crucible of 99.7% A1203 and dried, and during the heating treatment step, it is treated at 600-1000 C to obtain a composition with a composition of 38Y (Cr0.5Mn0.5) O3.62Y203, the same as

  that of the thermistor device 1.

  Then, during the second step, the treatment is carried out in the same manner as in the working example 9 above, so that the powdered raw materials thus obtained are granulated. These granules are used in the molding and sintering steps to obtain the thermistor device 1 with wires

  conductors 11 and 12 fixed as a mixed sintered body.

  Subsequently, this thermistor device 1 assembled into a temperature sensor 100 in the same manner as in working example 9 above, was subjected to an evaluation of its resistance-temperature value characteristics (resistance value and resistance-temperature coefficient 3) and temperature accuracy (AC). Table 7 shows the results of the evaluation with the concentration of citric acid. It should be noted that Table 7 also shows the results of the evaluation of Work Examples 19-23 below. The temperature sensor 100 according to this example has shown a temperature accuracy of

   5 C, which is an excellent value.

  In addition, the thermistor device 1 of this example was subjected to a quantitative analysis of the various constituent elements of Y, Cr and Mn by means of an electron probe mass analysis (EPMA). The results are given in Table 8. It should be noted that Table 8 also shows the results of the analysis of Working Examples 19 to 23 below as well as the results of the analysis of Comparative Example 3.

mentioned above.

  As is apparent from Table 8, the dispersion in the composition of various constituent elements (standard deviation α, units of% atoms) was found to be reduced by approximately 1/2 of that of the phased method. conventional solid. Moreover, in the conventional solid phase method (Comparative Example 3), the dispersion in the composition was greater than in the liquid phase method, so this increase in dispersion in the composition was confirmed as the cause of the degradation of

the temperature accuracy.

  (Work Example 19) Work Example 19 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cr0, o5Mn0.5) O3.62Y203 is obtained by the same method of manufacture in Work Example 18 above shown in Figure 25, except that the concentration of complexing agent citric acid is changed to twice per mole. The precursors of the constituent elements react with this

  citric acid to obtain the raw material powder.

  The powdered raw material thus obtained is used in the second step mentioned above to obtain the thermistor device 1 with conductive wires 11 and 12 fixed as a mixed sintered body of 38Y (Cr0.5Mn0.5) 03.62Y203. This thermistor device assembled into a temperature sensor 100 has been subjected to an evaluation of its resistance-temperature value characteristics (resistance value and resistance-temperature coefficient P) and the temperature accuracy (AC) in the same manner as in

  Work Example 9 above (see Table 7).

  The temperature sensor 100 according to this example in which the citric acid concentration was adjusted to 2 times per mole showed a temperature accuracy of 4 C, which is an excellent value. Moreover, in this example as well, the results of the EPMA analysis (see Table 8) confirmed that the dispersion in the composition of the constituent elements was reduced by approximately 1/3 of that in the method.

conventional solid phase.

  (Work Example 20) Work Example 20 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cr 0.5Mn 0.5) O 3.62Y 2 O 3 is obtained by the same process

  of manufacture than in working example 18

  25, except that the concentration of citric acid of complexing agent is changed to four times per mole. The precursors of the constituent elements react with citric acid to obtain the powdered raw material. The powdered raw material thus obtained is used in the second step mentioned above to obtain the thermistor device 1 with lead wires 11 and 12 attached as a mixed sintered body of 38Y (Cr0.5Mn0.5) 03.62Y203. This thermistor device 1 assembled into a temperature sensor 100 was subjected to an evaluation of its resistance-temperature value and temperature accuracy characteristics (A C) in the same manner as in the example

  9 above (see Table 7).

  The temperature sensor 100 according to this example in which the citric acid concentration was adjusted to four times per mole showed a temperature accuracy of 3 C, which is an excellent value. In addition, in this example as well, the results of the EPMA analysis (see Table 8) confirmed that the dispersion in the composition of the constituent elements was reduced to approximately 1/3 to 1/4 of that according to the method.

in conventional solid phase.

  (Work Example 21) Work Example 21 is an example in which the powdered raw material for the thermistor device 1 consisting of a mixed sintered body of 38Y (Cr0.5Mn0.5) 03.62Y203 is obtained by the same process

  of manufacture than in working example 18

  25, except that the concentration of the complexing agent citric acid is changed to ten times per mole. The precursors of these constituent elements react with this citric acid to obtain the powdered raw material. The powdered raw material thus obtained is used during the second step mentioned above to obtain the thermistor device 1 with conductive wires 11 and 12 fixed as a mixed sintered body of 38Y (Cr0.5Mn0.5) 03.62Y203. This thermistor device 1 assembled into a temperature sensor 100 was subjected to an evaluation of its resistance-temperature value and temperature accuracy characteristics (A C) in the same manner as in the example

  9 above (see Table 7).

  The temperature sensor 100 according to this example in which the citric acid concentration was adjusted to ten times by weight showed a temperature accuracy of 1.5 C, which is an excellent value. In addition, in this example as well, the results of the EPMA analysis (see Table 8) confirmed that the dispersion in the composition of the constituent elements was reduced to approximately 1/4 of that in the

  conventional solid phase method.

  (Work Example 22) Work Example 21 is an example in which the powdered raw material for the thermistor device 1 consists of a mixed sintered body of 38Y (Cro0.5Mn0.5) 03. 62Y203 is obtained by the same process

  of manufacture than in working example 18

  25, except that the concentration of the complexing agent citric acid is changed to twenty times per mole. The precursors of the constituent elements react with this

  citric acid to obtain the raw material powder.

  The powdered raw material so obtained is used during the second step mentioned above to obtain the thermistor device 1 with lead wires 11 and 12 attached as a mixed sintered body of 38Y (Cro, 5Mn0.5) O3.62Y203. This thermistor device 1 assembled into a temperature sensor 100 was subjected to an evaluation of its resistance-temperature value and temperature accuracy characteristics (A C) in the same way as in the example

  9 above (see Table 7).

  The temperature sensor 100 according to this example in which the citric acid concentration was adjusted to twenty times by weight showed a precision of

  temperature of 1.5 C, which is an excellent value.

  In addition, in this example as well, the results of the EPMA analysis (see Table 8) confirmed that the dispersion in the composition of the constituent elements was reduced to approximately 1/4 of that in the

  conventional solid phase method.

  (Work Example 23) Work Example 23 is an example in which the powdered raw material for the thermistor device 1 consists of a mixed sintered body of 38Y (Cr0.5MnO, 5) O3. 62Y203 is obtained by the same process

  of manufacture than in working example 18

  25, except that the concentration of the complexing agent citric acid is changed to thirty times per mole. The precursors of the constituent elements react with this

  citric acid to obtain the raw material powder.

  It should be noted that when the concentration of citric acid is up to twenty times per mole as

  in working examples 18 to 23 mentioned above.

  above, the polymer thus obtained was a gelatinous viscous liquid, but when the concentration of citric acid becomes 30 times by weight as in this example, the polymer does not become a viscous liquid

At 2775537

  gelatinous, but rather a part becomes a soil

  fixed colloidal dispersed in the liquid.

  Therefore, in order to avoid dispersion from the ideal thermistor composition, in the drying step mentioned above, the entire amount of the fixed sol and liquid was placed in the aluminum crucible mentioned above. above and dried. Thus, through the heat treatment process, the powdered raw material with a composition of 38Y (Cr0.5Mn0.5) O3.62Y203, the same as that of the device

of thermistor 1, is obtained.

  The powdered raw material thus obtained is used during the second step mentioned above to obtain the thermistor device 1 with conductive wires 11 and 12 attached as a mixed sintered body of 38Y (Cr0.5Mn0.5) O3.62Y203. This thermistor device 1 assembled into a temperature sensor 100 was subjected to an evaluation of its resistance-temperature value and temperature accuracy characteristics (+ A C) in the same way as in the example

  9 above (see Table 7).

  The temperature sensor 100 according to this example in which the citric acid concentration was adjusted to thirty times per mole showed a temperature accuracy of 8 C, which was an excellent value. In addition, in this example as well, the results of the EPMA analysis (see Table 8) confirmed that the dispersion in the composition of the constituent elements was reduced to approximately 1/2 of that in the

  conventional solid phase method.

Table 7

  Concentration Resistance value (kf) Coefficient Accuracy of citric acid Resistance temperature 1000 C temp. (C) (27QC) p (K) Example of work 181 times per mole 50 0707 2580 +5 Example of work 192 times per mole 50 0.07 2580 +4 Work example 204 times per mole 50 007 2580 3 Work example 2110 times per mole 50 0.07 2580 +1;

  Example of, tra ai2fo s ar mol0258.

  Example of work 2220 times per mol 50 0 07 2580 15 o Work example 2330 times per mole 100 0X20 2440 i8 -q Co! '

Table 8

  Acid concentration Dispersion of composition 7 (at%)

I Acid concentration.

  citric Y Cr I Mn Example of work 18 1 time per mole 0 64 0.31 0, 19 Example of work 2 times per mole 46 014 m = pe-work-OE-4,074 6 0/259 i 0 ', Example of Work 4 times per mole 0-100 Example of Example 21 --- 1 time per mole 032 0.23 00 Example-of-work 22 20 moles per mole 0X - 31 0.23 d 0.10 Example of work 123 30 times per mole 0.60 0.32.021 Comparative Example 3.. 1_2 068.22 06., 39 (Examples of other modifications of the second aspect)

  Here follows a description of the other modes of

  realization and other examples of work of the second aspect. In the working examples 9 and the equivalents mentioned above, organometallic compounds of metal alkoxide are used as the precursor substances, and an alcohol-containing liquid is used as the solvent, but it is also possible to use other organometallic compounds which are stable when present in benzene, xylene or other aromatic solvents, for example SYM-SYOl (trademark, produced by Symetrix Corp :) or the like may be used for the compounds Y ( yttrium). In addition, it is possible to use inorganic metal compounds which are stable when present in organic ester solvents, for example Y-03 (trademarked by Kojundo Chemical Laboratory Co., Ltd.) or the like. In addition, in working examples 9 and the equivalents mentioned above, organometallic compounds of single metal alkoxides are used as the precursor substances, but it is also possible to use metal alkoxides of multiple metal elements such as a metal alkoxide containing Y, Cr and Mn (a composite alkoxide), or a composite alkoxide containing Y, Ca, Cr, Fe and Ti, or a composite alkoxide containing Al , Cr, and Fe and a composite alkoxide containing Mg and Ca to prepare the powdered thermistor raw metal in the same manner as in the working example 9 mentioned above. In addition, in previous work examples 13, 15 and 17, EDTA is used as the complexing compound, but other complexing compounds which are stable to coordinate metal ions can be used, for example, citric acid, acetate, oxalate, stearate or the like may be used to prepare the powdered thermistor raw material in the same manner as in

  the example of work mentioned above 10.

  In addition, in the preceding examples 9 to 23, a compact, mass-type, cylindrical thermistor device with dimensions of 1.6 mm in diameter and 1.2 mm in length, for example, is obtained, but in the present invention the shape of the thermistor device 1 does not matter. For example, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor device, to adjust its viscosity or hardness to be suitable for sheet formation, and so get a thermistor sheet in

  leaf shape with a thickness of 200 im.

  The thickness of four of these laminated sheets together becomes 1 mm, so the same beneficial effects of the work examples mentioned above can be obtained with a type of thermistor device.

  laminated sheet with conductive wires attached.

  In addition, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor device, to adjust its viscosity or hardness to be suitable for extrusion molding, and thus to use extrusion molding to obtain a molded thermistor device with orifices formed to attach conductive wires thereto, and then inserting the conductive wires and sintering together to obtain a thermistor device with attached lead wires, thus the same performance as in

  Previous work examples can be obtained.

  Moreover, in the working examples mentioned above 9 to 17, only single types of compounds have been used, such as precursor substances, that is to say, organometallic compounds, complexing compounds or inorganic metal compounds, but as long as the materials of a uniform composition can be obtained, it is possible to use a combination of precursors, such as a combination of inorganic metal compounds and organometallic compounds, such as the precursor compounds in the starting material, or a combination of organometallic compounds and complexing compounds such as precursor compounds in the

starting material.

  In addition, in the working examples mentioned above 9 to 17, the precursor compounds are mixed and dissolved in the alcohol, in demineralized water or various other solvents, but in order to effect the uniform mixing of the liquid mixture. to be prepared, other dispersion media or dispersing agents, or acids or bases for adjusting the pH (hydrogen ion concentration) can be added and the

  raw material for the thermistor device.

  Moreover, in the working examples mentioned above 9 to 11, the Y (Cro, 5Mno, 5) 03, which is the dominant phase of the resistance value, and the Y203, which is the high resistance phase are mixed and dissolved together by the precursor compounds to obtain the powdered raw material which has the ideal composition of the thermistor device, but it is also possible to prepare only the phase that dominates the resistance value by means of the liquid phase method to obtain a powdered raw material and mixing this powdered raw material with other compositions using a ball mill or other solid phase method. Even in this case, the temperature accuracy can be improved in comparison with a thermistor device obtained by the method

in conventional solid phase.

  In addition, in the embodiments mentioned above, the powdered raw material is prepared by means of a chemical liquid phase method in which an agent precipitating the metal salt is added to the liquid mixture of the precursor compounds, but steam pyrolysis methods, pyrolysis methods, freeze drying methods, solvent burning methods or other physical liquid phase methods can also be used to prepare the thermistor powder raw materials. Even in this case, the dispersion in the composition can be suppressed and the temperature accuracy can be improved in comparison with a thermistor device obtained by the conventional solid phase method. This method should be the third aspect, rather than the

second aspect.

  (Work Example 24) Work Example 24 is an example of using Y203 (raw material for M1) and Cr203 and Mn203 (both raw materials for M2) as the raw materials used to obtain the part of thermistor 13 consisting of a mixed sintered body of 38Y (Cr0o, 5Mn0.5) O3.62Y203 (a = 0.38, b = 0.62), and forming an anti-reduction coating 14 of Y203 (anti-reduction material) on the surface of this part

  thermistor 13 (see Figure 26).

  Fig. 29 shows the manufacturing method for the thermistor device of this working example 24. It should be noted that Fig. 29 also shows the method of manufacturing the examples of

work 25 to 28.

  Materials Y203, Cr203, Mn203 and CaCO3 each with a purity of 99.9% or more are prepared. In formulation 1 to obtain the desired resistance value and the resistance-temperature coefficient in the thermistor device 1, the Y203, Cr203 and Mn203 are weighed so that the coefficient a and b of aY (Cro, 5Mn0.5 ) O3.bY203 have the relation a: b = 38: 62 and the total weight is 2000 g. In addition, 36 g of CaCO3 are added to give a mixture of Y2O3 crude material,

  Cr203, Mn203 and CaCO3 with a total weight of 2036 g.

  Then, during the mixing step, in order to perform a fine grinding of the raw materials of

  thermistor, a media mixing mill is used.

  The media mixing mill in this example is a bead mill (manufactured by Ashizawa Co., Ltd., model RVIV, effective capacity: 1.0 liter, actual capacity: 0.5 liter). The grinding conditions for this bead mill necessitate the use of 3.0 kg of zirconia bales of 0.5 mm diameter as the grinding media, and that 80% of the volume of the chamber of

  mixing be filled with zirconia balls.

  The operating conditions are adjusted to a peripheral speed of 12 m / s and a rotational speed of 3110 revolutions / minute. It should be noted that 4.5 liters of distilled water were used as the dispersing agent for the 2036 g of raw material to be mixed, and the binder and dispersing agent were added simultaneously, followed by mixing and grinding. were carried out for 10 hours. A polyvinyl alcohol (PVA) binder was added in the amount of

  g for 2036 g of the raw material to be mixed.

  The thick paste of raw material after mixing and grinding process was evaluated using a laser granulometer and the results indicated that the average grain size was 0.4 μm (micrometer). The raw material pulp thus obtained is dried in a spray dryer under drying chamber inlet temperature conditions of 200 ° C. and

  an outlet temperature of 120 C (drying step).

  The granules of the thermistor raw material powder thus obtained were spherical with an average grain size of 30 μm and this raw material powder is placed in a crucible of 99.3% Al 2 O 3 and calcined for 1 to 2 hours at room temperature. 1100-1300 C in a high temperature oven in air to obtain a calcine Y (Cro, 5Mno, 5) O03.Y203 (calcination step). The above-mentioned calcine, which became a compact solid during calcination, was coarsely milled in a blender and grinder and passed through a mesh screen to obtain a Y powder. (Cro, 5Mno, 5) 03.Y203

(formulation 2).

  Then, during the milling step ("Mixing and Grinding" in Figure 29), in order to perform a fine grinding of the Y (Cr0o, 5Mn0.5) O3.Y203, a similar bead mill

  to that used in the mixing step mentioned above.

  above was used. The operating conditions of the bead mill are the same as those in the mixing step. In addition, during the milling step, a dispersing agent, a binder and a mold release agent were added and milled at the same time to obtain a thick paste. The raw material pulp of the thus ground thermistor materials was evaluated using a laser granulometer, and the results indicated that the

average grain size was 0.3 μm.

  The Y (Cro, 5Mn0.5) O3.Y₂O3 paste obtained after grinding is dried and granulated in a spray drier under the same conditions as in the drying step in order to obtain the Y (Cr0.5MnO.sub.5) granules. O3.Y203. These granules are used to

  mold the thermistor portion 13 of Figure 26.

  The molding step was carried out by a mold-molding method, in which Pt 100 conductive wires with dimensions (outer diameter x length) of 0.3 mm x 10.5 mm were inserted into a male mold. , and the pellets were placed in a female mold with an inside diameter

  1.89 mm. The molding was done at a pressure.

  approximately 1000 kgf / cm 2 to obtain a thermistor portion 13 molded with leads 11 and 12 attached. During the sintering step, this molded thermistor device is placed in a corrugated carrier made of A1203 and sintered for 1 to 2 hours at 1400- 1600 C in order to obtain a mass-type, compact, cylindrical thermistor portion. 13 with dimensions of 1.6 mm in diameter and 1.2 mm in length consisting of

  a mixed sintered body of. 38Y (Cr0,5Mn0,5) 03.62Y203.

  Next, an anti-reducer material is formed on the surface of this thermistor portion 13 with fixed conductive wires 11 and 12. First, during the dip coating step, an organometallic yttrium compound, which is the precursor to the Y203 anti-reduction material, is applied to the surface.

of this thermistor part 13.

  The application of the organometallic yttrium compound to the surface of the thermistor portion is performed using a Yttrium organometallic liquid solution (SYM-Y01, made by Smetrix Corp, USA). The dip coating is performed by immersing the thermistor portion 13 in this liquid and emerging. In this way, this organometallic yttrium compound, which is the precursor of the anti-reducer material Y203, is applied to the surface

of the thermistor part 13.

  Subsequently, the solvent contained in the liquid organometallic compound mentioned above yttrium can evaporate in the atmosphere at room temperature from room temperature to 40 C. By heating the thermistor portion 13 with the precursor mentioned in above it at a temperature of 1200 ° C, a thermistor device 1 is obtained with a film of thickness 0.5-5.0 ium of the anti-reducer material formed on the surface of the thermistor portion 13 as a coating anti-reducer 14 (Figure 26) (step of

coating formation).

  The thermistor device with lead wires 11 and 12 has been assembled as shown in Fig. 27 to obtain a temperature sensor 100. This temperature sensor 10a has been placed in a high temperature oven and its resistance characteristic ( resistance value, P, AR2) were evaluated over the temperature range

  starting from the temperature (for example 27 C) to 1000 C.

  Table 9 presents the results of the evaluation. I1

  Note that in the formula AR2 (%) = (Rmaxt / Rt) x10-

  , the stimulated temperature t is 600 C.

  The temperature sensor 10a of this working example 24 has shown a resistance value in the range of 50 to 100 kn in the temperature range from ambient temperature up to 1000 ° C, and thus has excellent value characteristics. résistancetempérature. Thus, a thermistor device that is stable to detect temperatures in a wide range of temperature

  ambient at 1000 C can be expected.

  Moreover, with the temperature sensor 100 of this working example 24, the maximum rate of resistance change AR2 for the thermistor device 1 inside the metal capsule has been found as

  showing a stable level of approximately 3%.

  For this reason, there is no need to perform the high temperature heat treatment (approximately 900 C) necessary to stabilize the resistance of the conventional device, and it is not necessary to use a capsule made of materials expensive, so it is possible to provide a temperature sensor that has a stable resistance value even when the temperature device 1 itself is subject to a

reducing environment.

  (Work Example 25) Work Example 25 is an example in which after obtaining a thermistor portion 13 in the same manner as in Work Example 24, a coating of A1203 is formed on the surface of this

  thermistor portion 13 as an anti-reducing material.

  The same process as in the working example is carried out until the sintering step to obtain a thermistor portion 13 with fixed leads 11 and 12. The thermistor portion 13 similarly consists of a mixed sintered body of 38Y (Cro, 5Mn0, 5) 03.Y203. Then, in the dip coating step, an aluminum organometallic compound (aluminum alkoxide in this example) which is the precursor of the Al 2 O 3 reducing material is applied to the surface of this thermistor portion 13. Liquid solution of an organometallic aluminum compound (SYM-A104, made by Symetrix Corp, USA) was used as a precursor to Al 2 O 3. In the same way as in working example 24, dip coating was used to form the precursor

  for the anti-reducing material A1203.

  Subsequently, in the coating forming step, in the same manner as in working example 24 the solvent is vaporized and heating is performed to obtain a thermistor device 1

  with a film thickness of 0.5-5.0 im of anti-

  The thermistor device 1 has been used to fabricate a temperature sensor 100 and its resistance-quench value characteristics have been evaluated in the same manner. Table 9 presents the results of the evaluation. The temperature sensor 100 of this example of work showed good resistance-temperature value characteristics in the same way as in the working example 24. In addition, the resistance change maximum AR2 for the thermistor device 1 inside the metal cover was

  found mounted at a stable level of roughly 2%.

  Therefore, it is possible to provide a thermistor with a performance similar to

that of the example above 24.

  (Work Example 26) Work Example 26 is an example in which after obtaining a thermistor portion 13 in the same manner as in Work Example 24, a coating of 3A1203.2SiO2 (mullite) is formed on the surface of this thermistor portion 13 as an anti-reducing material. The same procedure as in the working example is carried out until the sintering step to obtain a thermistor portion 13 with lead wires 11 and 12 attached. The thermistor portion 13 similarly consists of a mixed sintered body of 38Y (Cr0.5Mn0.5) O3.62Y203. Next, in the dip coating step, an organometallic compound of aluminum and an organometallic compound of silicon ( both of which are alkoxides in this example) which are the precursor to the mulit of anti-reducing material, are applied to the

  surface of this thermistor part 13.

  A liquid solution of an organic compound

  aluminum (SYM-A104, made by Symetrix Corp, USA) and a liquid solution of an organometallic silicon compound (SYM-SI04, made by Symetrix Corp., USA) are used as the mullite precursors The solution of an organometallic compound of aluminum and the liquid solution of an organometallic silicon compound have been distributed so that a formulation of 3A1203.2SiO2 is formed after burning, and a liquid mixture of the liquid solution of a organometallic compound of aluminum and a liquid solution of an organometallic compound of

silicon has been prepared.

  The application of the anti-reducer material to the surface of the thermistor portion 13 is carried out by immersion coating in the same manner as in the working example 24 in which the thermistor portion 13 is immersed in the liquid mixture and emerged. In the same way, the precursor to the material

  anti-mullite reducer is formed.

  Subsequently, during the coating forming step, in the same manner as in working example 24, the solvent contained in the liquid mixture is vaporized and heating is performed to obtain a thermistor device 1 with a film 0.5-5.0 μm thickness of anti-reducer material formed on the surface of the heat resistance portion 13 as an anti-reducer coating 14. The thermistor device 1 was used to make a temperature sensor 100 and

  its resistance value characteristics-

  tempers were evaluated in the same way. Table 9 presents the results of the evaluation. The temperature sensor 100 of this example of work 26 showed good resistance-temperature value characteristics in the same way as in the working example 24. Maximum resistance change AR2 for the thermistor device 1 within the metal cover was found to be at a steady level of approximately 1.5%. Therefore, it is possible to provide a thermistor with a performance similar to that of

example 24.

  (Work Example 27) Work Example 27 is an example in which, after obtaining a thermistor portion 13 in the same manner as in Work Example 24, a Y3A15012 coating is formed on the surface of

  this part of thermistor 13 as anti-corrosion material

  reducer. The same procedure as in the working example 24 is carried out until the sintering step to obtain a thermistor portion 13 with lead wires 11 and 12 fixed. The thermistor portion 13 similarly consists of a mixed sintered body of 38Y (Cr0.5Mn0.5) 03.62Y203. Next, during the dip coating step, an organometallic compound of yttrium and an organometallic compound of aluminum ( both of which are alkoxides in this example), which are the precursors to the anti-reducing material Y3A15012, are applied to the

  surface of this thermistor part 13.

  A liquid solution of an organic compound

  yttrium metal (SYM-A104, made by Symetrix Corp, USA) and a liquid solution of an organometallic silicon compound (SYM-YO1, made by Symetrix Corp., USA) and a liquid solution of an organometallic compound of Aluminum (SYM-ALO4, made by Symetrix Corp., USA) was used as the precursor. The liquid solution of an organometallic yttrium compound and the liquid solution of an organometallic aluminum compound were prepared so that a formulation of Y3A15012 is formed after burning, and a liquid mixture of the liquid solution of an organometallic compound of yttrium and the liquid solution of an organometallic compound

of aluminum has been prepared.

  The application of the anti-reducer material to the surface of the thermistor portion 13 is formed by immersion coating in the same manner as in the working example 24 in which the thermistor portion 13 is immersed in this liquid mixture and emerged. In this way, the precursor to the material

  anti-mullite reducer is formed.

  Subsequently, during the coating forming step, in the same manner as in working example 24, the solvent contained in the liquid mixture is vaporized and heating is performed to obtain a thermistor device 1 with a film 0.5-5.0 μm thickness of the anti-reducer material formed on the surface of the heat resistance portion 13 as anti-reducer coating 14. The thermistor device 1 was used to fabricate a temperature sensor 100 and its Resistance value-quench characteristics were evaluated in the same way. Table 9 shows the results of the evaluation The temperature sensor 100 of this example of work 27 showed good resistance-temperature value characteristics in the same way as in the working example 24. In addition, the The maximum change in the AR2 resistance for the thermistor device 1 within the metal cover was found to be at a steady level of approximately 2.0%. Therefore, it is possible to provide a temperature sensor that has a stable resistance value even when the thermistor device 1 itself is subject to a reducing environment. (Work Example 28) Work Example 28 is an example in which, after obtaining a thermistor portion 13 in the same manner as in Work Example 24, a Y3SiO5 coating is formed at the surface of this

  part of thermistor 13 as an anti-material

  reducer. The same procedure as in working example 24 is carried out until the sintering step to obtain a thermistor portion 13 with fixed wires 11 and 12. The thermistor portion 13 similarly consists of a mixed sintered body

of 38Y (Cr 0.5MnO.5) O3.62Y203.

  Then, during the dip coating step, an organometallic yttrium compound and an organometallic silicon compound (both alkoxides in this example), which are the precursor to the Y3SiO5 anti-reducing material, are applied to the

  surface of this thermistor part 13.

  A liquid solution of an organic compound

  yttrium metal (SYM-YO1, made by Symetrix Corp, USA) and a liquid solution of an organometallic silicon compound (SYM-SI05, made by

  Symetrix Corp., USA) were used as a precursor.

  The liquid solution of an organometallic yttrium compound and the liquid solution of an organometallic silicon compound have been dispensed into a formulation such that Y3A15012 is formed after heating, and a liquid mixture of the liquid solution of a compound organometallic yttrium and a liquid solution of an organometallic silicon compound was prepared. The application of the anti-reducer material to the surface of the thermistor portion 13 is carried out by immersion coating in the same manner as in the working example 24 in which the thermistor portion 13 is immersed in this liquid mixture and emerged. In this way, the precursor to the material

  anti-mullite reducer is formed.

  Subsequently, in the coating forming step, in the same manner as in working example 24, the solvent contained in the liquid mixture is vaporized and heating is performed to obtain a thermistor device 1 with a film 0.5-5.0 pim thickness of the anti-reducer material formed on the surface of the heat-resistance portion 13 as an anti-reducer coating 14. The thermistor device 1 was used to manufacture a temperature sensor 100 and

  its resistance value characteristics-

  tempers were evaluated in the same way. Table 9 shows the results of the evaluation The temperature sensor 100 of this example of work 28 showed good resistance-temperature value characteristics in the same way as in the working example 24. Maximum change of the AR2 resistance for the thermistor device 1 inside the metal cover showed a stable level of overall 3.0%. Therefore, it is possible to provide a temperature sensor that has a stable resistance value even when the thermistor device 1 itself is

  subject to a reducing environment.

Table 9

  Resistance value Coefficientaxa3mmd E - (ee Composition of Composition Value of resis-lCoefficient aIsais 9anceà 'i

resistance to interference

  the anti-reduction part kn) resistor of the thermistor capsule RT metal temperature AR2 Ex mp e8Y Cr 5M o5 (27 CJ1000C / (K) 600 0C) _example_ de3Y (CroMno 5 4 _ _ work 2403 -62Y203 Y20350 14 2450 430 Example of A1203 + 2O

Work 25 -

  Y203 - 50 - - n Example of 3Al203 * 2SiO2 Ln Example of "e Y3A15012" "5 +210 Example ofà, jn +3/0 work 28 _ Example of LA z 3.2SiOS, | .302" "+1; 5o work 260 (Work Example 29) Work Example 29 is an example of obtaining the thermistor portion 13 consisting of a mixed sintered body of 40Y (Cr0.5Mn0.5) O3.60A1203 (a = 0.40). , b = 0.60), and forming an anti-reduction coating 14 of Y203 (anti-reducer material) on the

  surface of this thermistor part 13.

Fig. 30 shows the manufacturing method for the thermistor device of this working example 29. It should be noted that Fig. 30 also shows the method of manufacturing the examples.

working 30 to 33.

  Materials Y203, Cr203, Mn203 and CaCO3, each with a purity of 99.9% or more are prepared. In formulation 1, so that the composition of Y (Cro, 5MnO, 5) O3 is obtained after calcination, Y203, Cr203 and Mn203 are weighed so that the molar ratio Y: Cr: Mn becomes 2: 1: 1 and that the total weight is 2000 g. In addition, 36 g of CaCO3 are added to give a raw material mixture of Y203, Cr2O3, Mn2O3 and CaCO3 with a

total weight of 2036 g.

  Then, during the mixing step, in order to perform a fine grinding of this mixture of raw material, a medium mixing mill is used. The media mixing mill in this example is the

  same bead mill as in working example 24.

  The mixing conditions, the operating conditions and the amount of dispersing agent and binder added were the same as in the example of

work 24.

  The raw material paste after the mixing and milling process was evaluated using a laser granulometer, and the results indicated that

  the average grain size was 0.3 μm.

  The raw material paste thus obtained is dried in a spray drier under the same conditions as in the working example 24 (drying step). The thermistor raw material powder thus obtained is placed in a crucible of 99.3% Al 2 O 3 and calcined for 2 to 3 hours at 1100 ° -1300 ° C. in a furnace at high temperature in air to obtain

  a calcine of Y (Cro, 5Mno, 5) 03 (calcination step).

  Then, in formulation 2, the above-mentioned calcine, which became a compact solid during calcination, was comminuted in a blender and milling machine and passed through a sieve of mesh size. 30 # to obtain a powder of Y (Cro, 5Mno, 5) O3. In addition, this powder of Y (Cro, 5MnO, 5) O 3 and Al 2 O 3 with a purity of 99.9% or more is prepared. Both are weighed 1S so that the molar ratio of formulation of the two (a: b) Y (Cr0.5Mn0.5) O3: Al2O3 becomes 40:60 and that the weight

total of 2000 g.

  Then, during the milling step ("Mixing and milling" in Figure 30) the weighed mixture was mixed and milled using a bead mill from the mill.

  same way as in the mixing step mentioned above.

  above. Operating conditions for the crusher

  bead are the same as those of the mixing step.

  In addition, during this grinding step, a dispersing agent, a binder and a mold releasing agent were added and milled at the same time to obtain a paste. The pulp of raw material after the grinding process was evaluated using a laser granulometer, and the results indicated that the

average grain was 0.3 p1m.

  The raw material paste of Y (Cro, 5MnO, 5) O3 and Al2O3 obtained after grinding is dried and granulated in a spray drier under the same conditions as in the drying step to obtain mixed granules of Y (Cro, 5MnO, 5) O3.and A1203 (granulation and drying step). These granules are used

  to mold the thermistor device.

  The molding step was carried out by a mold molding method in the same manner as in working example 24, in which Pt 100 lead wires were inserted into a male mold, and the pellets were placed. in a mold

  female. The molding was carried out at the same pressure.

  to obtain a molded thermistor portion 13 with fixed lead wires 11 and 12. This molded thermistor portion 13 was subjected to a sintering step in the same manner as in working example 24 to obtain a thermistor portion 13

  with conductive wires 11 and 12 fixed.

  Next, dip coating is performed in the same manner as in Work Example 24, in which an organometallic compound

  of yttrium, which is the precursor of

  Y203 reducer, is applied to the surface of this portion of thermistor 13. Then, during the step of forming the coating, a thermistor device 1 with a film of thickness 0.5-5.0 pin of an anti-coating -reducer 14 of Y203, formed on the surface of the

  part of thermistor 13, is obtained.

  This thermistor device 1 was used to manufacture a temperature sensor 100 in the same manner as in the working example 24, and its resistance-temperature value characteristics (resistance value, δ, AR2) were evaluated from the same way as in the working example 24. The

  Table 10 presents the results of the evaluation.

  The temperature sensor 100 of this working example 24 showed good resistance-temperature value characteristics as in Example 24. In addition, the maximum resistance change rate AR2 for the thermistor device 1 inside metal lid showed a stable level of approximately 3%. Therefore, it is possible to provide a temperature sensor that has the same advantageous effects as in working example 24. (Work Example 30) Work Example 30 is an example of obtaining the same part of thermistor 13 than in the working example 29, and forming an anti-reduction coating of A1203 on the surface of the thermistor portion 13. The steps up to the heating step are performed in the same manner as in the working example 29 to obtain a thermistor portion 13 with fixed wires 11 and 12. The thermistor portion 13 consists of a mixed sintered body of 40Y (Cr0.5Mn0.5) 0360A1203, the same as

in the working example 29.

  Then, the formation of the anti-

  reducer 14 of the anti-reducer material Ai203 on the thermistor portion 13 is made in the same manner as in the working example 25. Thus, a thermistor device 1 with a film thickness of 0.5-5.0 pim of an anti-reducer coating 14 formed on

  the surface of the thermistor portion 13 is obtained.

  This thermistor device 1 was used to make a temperature sensor 100 in the same manner as in the working example 24, and its characteristics were evaluated in the same way. The

  Table 10 presents the results of the evaluation.

  The temperature sensor 100 of this working example 24 showed good resistance-temperature value characteristics as in Example 24. In addition, the maximum resistance change rate AR2 for the thermistor device 1 inside metal lid showed a stable level of 2.0%. Therefore, it is possible to provide a temperature sensor that has the same beneficial effects

than in the working example 24.

  (Work Example 31) Work Example 31 is an example of obtaining the same thermistor portion 13 as in Work Example 29, and forming an anti-reduction coating of 3A1203.2SiO2 (mullite ) on the surface of the thermistor portion 13. The steps up to the heating step are performed in the same manner as in the working example 29 to obtain a thermistor portion 13 with fixed conductor wires 11 and 12 . The thermistor portion 13 consists of a mixed sintered body of 40Y (Cr0.5Mn0.5) O360A1203, the

  same as in working example 29.

  Then, the formation of the anti-

  reducer 14 of the anti-reducer material 3A1203.2SiO2 (mullite) on the thermistor portion 13 is carried out

  in the same way as in the working example 26. Thus, a thermistor device 1 with a film thickness of 0.5-5.0

  Inm of an anti-reduction coating 14 formed on the surface of the thermistor portion 13 is obtained. This thermistor device 1 was used to make a temperature sensor 100 in the same manner as in the working example 24, and its characteristics were evaluated in the same way. The

  Table 10 presents the results of the evaluation.

  The temperature sensor 100 of this working example 24 showed good resistance-temperature value characteristics as in Example 24. In addition, the maximum resistance change rate AR2 for the thermistor device 1 inside metal lid showed a stable level of 1.5%. Therefore, it is possible to provide a temperature sensor that has the same beneficial effects

than in the working example 24.

  (Work Example 32) Work Example 32 is an example of obtaining the same thermistor portion 13 as in Work Example 29, and forming an anti-reduction coating of Y3A15012 on the surface of the thermistor portion 13. The steps up to the heating step are performed in the same manner as in the working example 29 to obtain a thermistor portion 13 with fixed lead wires 11 and 12. The thermistor portion 13 consists of a mixed sintered body of 40Y (Cr0.5Mn0.5) O3.60A1203, the same as

in the working example 29.

  Then, the formation of the anti-reduction coating 14 of the anti-reduction material Y3A15012 on the thermistor part 13 is carried out in the same way as in the working example 27. Thus, a thermistor device 1 with a film of thickness 0, 5-5.0 μm of an anti-reducing coating 14 formed on the surface of the thermistor portion 13 is obtained. This thermistor device 1 was used to make a temperature sensor 100 in the same manner as in working example 24, and its resistance characteristics were evaluated in the same way. Table 10

  represents the results of the evaluation.

  The temperature sensor 100 of this working example 24 showed good resistance-temperature value characteristics as in Example 24. In addition, the maximum resistance change rate AR2 for the thermistor device 1 inside metal lid showed a stable level of 2.0%. Therefore, it is possible to propose a temperature sensor that has the same effects

  advantageous than in the working example 24.

  (Work Example 33) Work Example 33 is an example of obtaining the same portion of thermistor 13 as in Work Example 29, and forming an anti-reduction coating of Y2SiO05 on the surface of the thermistor portion 13. The steps up to the heating step are performed in the same manner as in the working example 29 to obtain a thermistor portion 13 with fixed lead wires 11 and 12. The thermistor portion 13 consists of a mixed sintered body of 40Y (Cr0.5Mno0.5) 03.60A1203, the same as

in the working example 29.

  Then, the formation of the anti-

  reducer 14 of the anti-reducer material Y2SiO5 on the thermistor portion 13 is carried out in the same manner as in the working example 28. Thus, a thermistor device 1 with a thickness film 0.5-5.0 pin of an anti-reducer coating 14 formed on

  the surface of the thermistor portion 13 is obtained.

  This thermistor device 1 was used to make a temperature sensor 100 in the same manner as in working example 24, and its resistance characteristics were evaluated in the same way. Table 10 shows the results of

evaluation.

  The temperature sensor 100 of this working example 24 showed good resistance-temperature value characteristics as in the working example 24. In addition, the maximum resistance change rate AR2 for the thermistor device 1 to 1 The inside of the metal lid showed a stable level of 3.0%. Therefore, it is possible to provide a temperature sensor that has the same effects

  advantageous than in the working example 24.

Table 10

  Composition of Composition Resistance Value Coefficient Maximum Exchange Rate-

  the resistance-resistance part of the RT thermistor resistance inside temperature of the 406Y example (Co5l 'in203 50 0.07 2580 + 3a0 Example of "A1203. +210 work 30. Example of 30Y (Cr0. sMn2.5) work 31 3A12O2SiO2 ..... +5 Example of ,, Y3A1I5012 .. + 2 work 32 l + _

Example of

  EXAMPLE 7 Comparative Example 7 is an example of the use of Y 2 O 3, Cr 2 O 3 and Mn 2 O 3 as raw materials used to obtain the thermistor portion 13 consisting of a mixed sintered body of 38Y (Cr0.5Mn0.5) O3.62Y203 in the same manner as in working example 24 and not forming anti-reducing material on its surface. the device has the composition of the thermistor device 1 of the

  Figure 26 without anti-reducing coating 14.

  The thermistor device of this Comparative Example 7 was assembled as shown in Figure 26 above, to obtain a temperature sensor 100 and its resistance characteristics were evaluated in the same manner as in the working example. 24. The results are shown in Table 11. The temperature sensor 100 of this example showed a resistance value in the range of Q to 100 kΩ in the temperature range from room temperature to 10000 ° C, and thus has a

  excellent resistance value characteristic-

  temperature. However, the maximum resistance change ratio AR2 for the thermistor device 1 inside the metal cover showed a level of 30%, so its resistance value stability when the thermistor device itself is subjected to a reducing atmosphere is poor compared to

examples of work above.

  It should be noted that when the temperature sensor of this example was subjected to thermal aging of 900 Cx100 hours, the rate of change AR2 rose to a level of 5% and stabilized. Therefore, the thermal aging of 900 Cxl00 hours is necessary in order to stabilize the

  resistance of the thermistor device of this example.

  (Comparative Example 8) Comparative Example 8 is an example of the use of Y 2 O 3, Cr 2 O 3, Mn 2 O 3 CaCO 3 and Al 2 O 3 as raw materials used to obtain the thermistor portion 13 consisting of a mixed sintered body of Y (Cr 0.5 MnO 5 ) O3.62Y203 in the same manner as in the working example 29 and not forming an anti-reducing material on its surface. Namely, the device comprises the composition of the thermistor device 1 of Figure 26 without anti-reducing coating 14, the

  same way as in Comparative Example 7.

  The thermistor device of this Comparative Example 8 was assembled as shown in Comparative Example 7 above to obtain a temperature sensor 100, and its characteristics of

resistance were evaluated.

  The temperature sensor of this example also has

  excellent resistance value characteristics-

  temperature. However, the maximum resistance change rate AR2 for the thermistor device 1 inside the metal cover showed a level of%, so its resistance value stability when the thermistor device itself is subjected to reducing atmosphere is poor in comparison to

examples of work above.

  It should be noted that when the temperature sensor of this example was subjected to thermal aging of 900 Cx100 hours, the rate of change of resistance AR2 jumped to a level of 5% and stabilized. Therefore, thermal aging of 900 Cx100 hours is necessary in order to stabilize the resistance of the thermistor device

of this example.

Table 11

  Composition of the Part Resistance Value Coefficient Maximum Crisis Rate

  Coefficient of the thermistor requirement (resistance at the inside temperature of the temperature of the metal capsule Example 1 - (27nC) 1000 C f (K) R2 (600c)

Example_

  500.14 24 50- + 300m Comparative 7 38Y (Cro; sMno5s) 03-62YzO3 50 0.14 250 +0 Example 8140Y (Cro, 5sMno, 5> O36Oy2O3 50 0.07 2580 + 25/0 iComparative 81 40 (C1sM;) 3'0Y0 o0 (Examples of other changes in the fourth aspect)

  In addition to the working examples 24-33

  above, forming the anti-reduction material according to this aspect of the invention on the surface of conventional thermistor devices such as high temperature thermistor devices made primarily of Cr 2 O 3, thermistor devices with a corundum type composition of (Al, Cr, Fe) 203, thermistor devices with a single composition of perovskite of (Cr, Ti, Fe) O3, it is possible to provide a thermistor device which has stable characteristics without fluctuation in the resistance of the reducing atmosphere in the metal lid, thus the thermal aging of the

  temperature sensor is not necessary.

  In addition, in the working examples above, Y203, A1203, SiO2, Y3A15012, 3A1203 2SiO2 (mullite) and Y2SiO5 materials can be freely combined as the anti-reducing material to form an anti-reducing coating consisting of plurality of layers of anti-reducing material on the surface of the thermistor device, and the same effects

  merits described above can be obtained.

  In addition, in the working examples mentioned above 24 to 33, a compact cylindrical mass type thermistor device 1 with dimensions of 1.6 mm in diameter and 1.2 mm in length, for example, is obtained. but in the present invention, the shape of the

  thermistor device 1 does not matter.

  For example, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor device, to adjust its viscosity or hardness to be suitable for sheet formation, and thereby obtain a sheet-shaped thermistor sheet with a thickness of 200 a. The thickness of five of these sheets rolled together becomes 1 mm, so the same

  advantageous effects of the examples of work mentioned above.

  can be obtained with a sheet-type thermistor device laminated with wires

fixed conductors.

  In addition, it is possible to add binders, resin materials or the like which are mixed with the raw material for the thermistor device, to adjust its viscosity or hardness to be suitable for extrusion molding, and thus to use a extrusion molding to obtain a molded thermistor device with orifices formed to attach conductive wires thereto, and then inserting the conductive wires and sintering together to obtain a thermistor device with attached lead wires, and

  the same performance as in the examples of work

above can be obtained.

  Moreover, in the examples of work mentioned

  above 24 to 33, the precursors of the anti-

  Reduction used were the organometallic compounds alcoholates (metal alkoxides) containing only single metal elements, but liquid liquids alcoholates which contain more than one of the selected elements from the group of Y, Al and Si, can be used. For example, aluminum-yttrium liquids or organometallic compounds, organometallic yttrium-silicon compounds can be used to apply

  the precursors of the anti-reducing material.

  Moreover, in the working examples mentioned above 24-33, organometallic compounds have been used as precursors of the anti-reducing material, but nitrates, chloride salts, acetates, oxalates or the like can be used as precursors of the anti-reducing material, and their liquid solutions can be used to apply

  the precursors of the anti-reducing material.

  Moreover, in the working examples mentioned above 24 to 33, the methods of forming the anti-reducing material are given as an immersion coating, the representative wet manufacturing method, but other methods of forming the anti-reducing material. -reducing can be used to obtain a thermistor device with an anti-reducing material formed on the surface of the heat-resistant portion. Other wet manufacturing processes include: spray coating, flame coating, application, printing, electro-plating, electrophoresis and other methods of forming the anti-reduction material. In addition, the thermistor device can also be obtained by

  molding and heating the precursors to the anti-

  reducing to form the anti-reducing material.

  In addition, dry manufacturing processes include electron beam deposition, sputtering, and other physical vapor deposition (PVD), chemical vapor deposition (CVD) methods that can be used to form the material. anti-reducing. In addition, the thermistor device can also be obtained by molding and heating the precursors to the anti-reduction material.

  to form the anti-reduction material.

  The film thickness of the anti-reduction material can be adjusted freely according to the conditions

  operation of the various manufacturing processes.

  Moreover, in the working examples mentioned above 24 to 33, the anti-reduction material is formed on the surface of the thermistor portion after the sintering step, but by applying the precursors of the anti-reduction material to the Thermistor part after molding (molding step) during the manufacturing process shown in Figures 29 and 30, it is possible to obtain a thermistor device with an anti-reducing material formed on its surface, where they are

sintered simultaneously.

  In addition, during the manufacturing step shown in Figures 29 and 30, after the step of

  molding, the thermistor part is heated to 1200-

  1400 C to obtain a portion of heated thermistor,

  thus applying the precursors of the anti-

  reducing to this portion of heated thermistor and heating, it is also possible to obtain a thermistor device with an anti-reducing material formed to

its surface.

  In addition, in order to increase the force by which the anti-reduction material adheres to the thermistor device, it is possible to form a main layer (main layer) by means of a wet process method or a dry process method followed by forming a second layer of the anti-reduction material on the entire surface of said first layer by means of said wet method or dry process method, and thereby obtaining a

  thermistor to achieve the same beneficial effects.

  This main layer can be selected

  freely from the materials of anti-

  reducing Y203, Al2O3, SiO2, Y3A15012, 3A1203.2SIO2 (mullite) and Y2SiO5, and the composition ratio, concentration of precursor liquids, molding characteristics of the thermistor portion and the operating conditions of the various processes

  manufacturing can be ordered freely.

  In addition, in order to add or apply functions relating to the thermal expansion coefficient, the heat conductivity, the heat resistance or the like, it is possible to add other materials to said main layer and to said secondary layer, or composite adhesives may be used to obtain a more complex thermistor device, but the same effects

  Described advantages are always obtained.

  It should be noted that in the temperature sensor 100 of Figure 27 where the thermistor device of the various examples above is used, a structure without a metal cover 2 may also be used. As described above, the thermistor device of this aspect of the invention is intended to suppress the movement of oxygen atoms from the device to the exterior of the device in a reduction environment, and thus a

  device is adopted by what an anti-material

  reducing is formed on the surface of the thermistor part. Thus, the reduction of the thermistor device itself is suppressed and the stability of

resistance value is obtained.

  Therefore, in the thermistor device of the fourth aspect of the present invention, there is no need to perform thermal aging to stabilize the resistance, and there is no need to use a cover made of expensive special materials , also it is possible to provide a temperature sensor that has a stable rate

resistance change AR2.

- 172 -

Claims (5)

  A method of manufacturing a thermistor device having a sintered body, comprising: a step wherein a plurality of precursor compounds that contain metal elements are mixed in the liquid phase to form a liquid mixture, a step in which an agent metal salt precipitant is added to said liquid mixture to precipitate a gelatinous precipitate of metal salts containing a plurality of said metal elements, a step wherein said precipitate is subjected to drying and a heat treatment to form a powdered raw material which is a powder composition containing a plurality of said metal elements, and a step in which said raw material in   powder is sintered to form said sintered body.   2 - Method of manufacture according to claim 1 wherein, during said formation of a liquid mixture, said plurality of precursor compounds are mixed in the liquid phase with a complexing compound which has at least two carboxyl groups as a coordination site and a at least one other coordination site, for forming said liquid mixture, and said plurality of precursor compounds and said complexing compound react in said liquid mixture to form a complex composite metal compound in which at least one of said elements metal is coordinated.   3 - Method according to claim 2, characterized in that ethylenediaminetetraacetic acid (EDTA) or acid   citric is used as said complexing compound. - 173 -   4 - Method according to any one of   Claims 1 to 3, characterized in that a compound   or organometallic compounds selected from metal alkoxides, metal acetylacetonates or meta carboxylates, are used as precursor compounds. - Method of manufacturing a device   thermistor according to any one of the claims   1 to 3, characterized in that one or more inorganic metal compounds selected from the group of nitrate compounds, oxynitrate compounds, chlorides and oxychlorides are used as precursor compounds. A method of manufacturing a thermistor device comprising a sintered body comprising: a step in which a plurality of precursor compounds that contain metal elements are mixed in the liquid phase to form a liquid mixture, a step in which a powder raw material which is a powder composition containing a plurality of said metal elements is formed from said liquid mixture, and a step in which said raw material in   powder is sintered to form said sintered body.   7 - Temperature sensor, characterized in that it contains a thermistor device which is manufactured by one of the manufacturing methods according to the   claims 1-6, and in that the dimension of   grains of said sintered body is smaller than 1 μm.