JP5053563B2 - Conductive oxide sintered body, thermistor element using the same, and temperature sensor using thermistor element - Google Patents

Description

  The present invention relates to a conductive oxide sintered body having conductivity and a resistance value that varies with temperature, a thermistor element using the same, and a temperature sensor using the same.

Conventionally, a conductive oxide sintered body that has conductivity and whose resistance value (specific resistance) varies depending on temperature, a thermistor element that performs temperature measurement using the sintered body, and a temperature using this thermistor element Sensors are known (Patent Documents 1 and 2).
Among these, Patent Document 1 contains Sr, Y, Mn, Al, Fe and O as thermistor elements capable of detecting temperature over a range of 300 ° C. to 1000 ° C., and includes perovskite oxides and garnet oxides. A sintered body for a thermistor element containing each crystal phase and containing at least one crystal phase of Sr—Al-based oxide and Sr—Fe-based oxide is disclosed.
Further, in Patent Document 2, as a conductive oxide sintered body having an appropriate specific resistance value in a range from room temperature to 1000 ° C., it is expressed by M1aM2bM3cM4dO ₃ , and a, b, c, and d are predetermined conditional expressions. A satisfactory conductive oxide sintered body is disclosed.

JP 2004-221519 A JP 2003-183075 A

As an application of the thermistor element and temperature sensor, there is an exhaust gas temperature measurement from an internal combustion engine such as an automobile engine. In these applications, in recent years, thermistor elements are required to detect temperature in a high temperature region around 900 ° C. in order to protect DPF and NOx reduction catalyst.
On the other hand, in order to detect a failure (disconnection) of a temperature sensor in an OBD system (On-Board Diagnostic systems) or the like, it is desired that the temperature can be detected even at a low temperature such as when the engine is started or when a key is turned on. In this case, particularly in cold regions, the starting temperature may be below freezing point, so a thermistor element capable of measuring temperature even at −40 ° C. is desired.

However, the above-mentioned Patent Documents 1 and 2 disclose a thermistor element or a sintered body capable of measuring temperature at room temperature or in the range of 300 ° C. or higher to 1000 ° C., and an appropriate resistance change is achieved in this temperature range. As described above, the temperature gradient constant (B constant) is about 4000 K or more (see, for example, Table 4 of Patent Document 2).
For this reason, the thermistor element or thermistor element using these sintered bodies has a large temperature gradient constant (B constant), and the resistance value of the thermistor element becomes too high at a low temperature of −40 ° C. Temperature measurement becomes difficult because measurement becomes difficult.

  The present invention has been made in view of such problems, and in a temperature range from a low temperature of −40 ° C. to a high temperature range of 900 ° C. or higher, a conductive oxide sintered body capable of appropriately detecting temperature, An object is to provide a thermistor element using the same and a temperature sensor using the thermistor element.

The solution means that one or more elements selected from Y, Nd, and Yb are M1, one or more elements selected from Mg, Ca, and Sr are M2, and one selected from Mn and Fe when the seed or more elements M3, is expressed by the composition formula _{M1 a M2 b M3 c Al d} Cr e O f, a conductive sintered oxide that have a perovskite crystal structure, a , B, c, d, e, and f are conductive oxide sintered bodies that satisfy the following conditional expression.
0.600 ≦ a ≦ 1.000
0 ≦ b ≦ 0.400
0.150 ≦ c <0.600
0.400 ≦ d ≦ 0.800
0.005 ≦ e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.80 ≦ f ≦ 3.30

The conductive oxide sintered body of the present invention in which a, b, c, d, e, and f satisfy the above-described conditional expression has a temperature gradient constant (B constant) in the temperature range of −40 ° C. to + 900 ° C. of 2000. The temperature can be appropriately measured in such a wide temperature range.
Moreover, the conductive oxide sintered body of the present invention has a perovskite (ABO ₃ ) crystal structure. Usually the A site (M1 _a M2 _{b), B} site a composition represented by a _{(M3 c Al d Cr e)} (M1 a M2 b) (M3 c Al d Cr e) O 3. However, a, b, c, d, and e satisfy the above-described conditions.
In the case of such a crystal structure, the elements M1 and M2 occupying the A site have close ionic radii and can be easily replaced with each other, and there are few by-products formed of these elements. Exist stably in the substituted composition. Similarly, the elements M3, Al, and Cr occupying the B site have close ionic radii and can be easily replaced with each other, and the generation of by-products composed of these elements is small and replaced. Stable in composition. Therefore, the specific resistance value of the conductive oxide sintered body and its temperature gradient constant (B constant) can be adjusted by continuously changing the composition ratio in a wide composition range.
In addition, in the conductive oxide sintered body of the present invention, the element M1 is one or more elements selected from Y, Nd, and Yb, and the element M2 is one or more elements selected from Mg, Ca, and Sr. The above elements are used, and the element M3 is one or more elements selected from Mn and Fe. By selecting these elements, it is preferable that the B constant in the above range can be obtained stably.

  In addition, the average particle diameter which shows the magnitude | size of the crystal particle which comprises an electroconductive oxide sintered compact becomes like this. Preferably it is 7 micrometers or less, More preferably, it is 0.1-7 micrometers, More preferably, it is 0.1-3 micrometers. If the average particle diameter of the crystal particles becomes too large, a conductive oxide sintered body with a deviation in the target material composition may be obtained. The characteristics of the sintered body or the thermistor element using the sintered body may be obtained. This is because it tends to cause instability.

Furthermore, the conductive oxide sintered body may be a conductive oxide sintered body in which the a and b satisfy the following conditional expression.
0.600 ≦ a <1.000
0 <b ≦ 0.400

  In the conductive oxide sintered body of the present invention, 0.600 ≦ a <1.000 and 0 <b ≦ 0.400, that is, a <1.000, b> 0. That is, this sintered body contains at least one element M1 of the 3A group elements excluding La, and at least one element M2 of the 2A group as essential components, and a and b are the above-described conditional expressions. It has the composition which satisfy | fills. In this conductive oxide sintered body (or a thermistor element using the same), even when a large number of these are produced as compared with those containing no element M2 (b = 0), each conductive oxidation There is an advantage that it is possible to reduce the characteristic variation between the individual sintered compacts (thermistor elements) and the characteristic variation between the firing lots.

Furthermore, the conductive oxide sintered body may be a conductive oxide sintered body in which a, b, c, d, e, and f satisfy the following conditional expressions.
0.820 ≦ a ≦ 0.950
0.050 ≦ b ≦ 0.180
0.181 ≦ c ≦ 0.585
0.410 ≦ d ≦ 0.790
0.005 ≦ e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.91 ≦ f ≦ 3.27

In the conductive oxide sintered body of the present invention in which a to f satisfy the above-described conditional expression, the B constant in the temperature range of −40 ° C. to 900 ° C. can be more reliably adjusted to the range of 2000 to 3000K. it can.
Moreover, in this conductive oxide sintered body in which a to f satisfy the above-described conditional expression, a plurality of conductive sintered bodies (thermistor elements using the same) in which a to f are specified to a certain numerical value are also manufactured. The variation among individual conductive sintered bodies (thermistor elements) and the variation among firing lots can be further reduced.

Furthermore, it is preferable to use a conductive oxide sintered body in which a, b, c, d, e, and f satisfy the following conditional expressions.
0.850 ≦ b ≦ 0.940
0.060 ≦ b ≦ 0.150
0.181 ≦ c ≦ 0.545
0.450 ≦ d ≦ 0.780
0.005 ≦ e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.92 ≦ f ≦ 3.25

  Alternatively, the conductive oxide sintered body according to any one of the above, wherein the element M1 is Y, the element M2 is Sr, and the M3 is Mn. good.

  In particular, in the conductive oxide sintered body of the present invention, the element M1 is Y, the element M2 is Sr, and the element M3 is Mn. Thereby, it is easy to obtain a B constant in the above range stably, which is preferable.

  In addition, depending on the firing conditions (the firing atmosphere such as oxidation and reduction, and the firing temperature) when producing the conductive oxide sintered body of the present invention, and the substitutional ratio of elements at the A site and B site, Oxygen excess or deficiency may occur. Therefore, even if the molar ratio of oxygen atom to (M1aM2b) and the molar ratio of oxygen atom to (M3cAldCre) in the above composition formula are not exactly 3: 1, the perovskite-type crystal structure is It only has to be maintained.

  Further, a thermistor element using the conductive oxide sintered body according to any one of the above is preferable.

  Since the thermistor element of the present invention uses the above-mentioned conductive oxide sintered body, it becomes a thermistor element having an appropriate temperature gradient constant capable of temperature measurement over a wide temperature range of −40 to 900 ° C.

  Furthermore, a temperature sensor using the thermistor element is preferable.

  In the temperature sensor of the present invention, since the thermistor element using the conductive oxide sintered body is used, the temperature sensor can measure the temperature over a wide temperature range of −40 to 900 ° C.

  An example of the thermistor element 2 using the conductive oxide sintered body 1 according to the present invention will be described in comparison with a comparative example.

(Examples 1-8)
First, manufacture of the electroconductive oxide sintered compact 1 and the thermistor element 2 concerning Examples 1-8 and Comparative Examples 1 and 2 is demonstrated. As raw material powder, Y ₂ O ₃ , SrCO ₃ , MnO ₂ , Al ₂ O ₃ , Cr ₂ O ₃ (all commercially available products with a purity of 99% or more) were used, and the chemical formula (composition formula) YaSrbMncAldCreO ₃ and The raw material powder mixture was prepared by weighing each of the raw material powders so that a, b, c, d, and e would be the number of moles shown in Table 1, and wet mixing and drying these raw material powders. Subsequently, this raw material powder mixture was calcined for 2 hours at 1400 ° C. in an air atmosphere to obtain a calcined powder having an average particle diameter of 1 to 2 μm. Thereafter, wet mixing and pulverization were performed using a resin pot and high-purity Al ₂ O ₃ boulder using ethanol as a dispersion medium.

Next, the obtained slurry was dried at 80 ° C. for 2 hours to obtain a thermistor synthetic powder. Thereafter, 20 parts by weight of a binder mainly composed of polyvinyl butyral is added to 100 parts by weight of the thermistor synthetic powder, mixed and dried. Furthermore, it granulated through the sieve of a 250 micrometer mesh, and the granulated powder was obtained.
In addition, as a binder which can be used, it is not specifically limited to the above-mentioned polyvinyl butyral, For example, polyvinyl alcohol, an acrylic binder, etc. are mentioned. The amount of the binder is usually 5 to 20 parts by weight, preferably 10 to 20 parts by weight, based on the total amount of the calcined powder.
Moreover, when mixing with a binder, it is preferable that the average particle diameter of the thermistor synthetic powder is 2.0 μm or less, whereby uniform mixing is possible.

Subsequently, the above granulated powder was used for press molding (press pressure: 4500 kg / cm ³ ) by a die molding method, and a pair of electrode wires 2a and 2b made of Pt—Rh alloy as shown in FIG. A non-fired molded body having a hexagonal plate shape (thickness: 1.24 mm) in which one end thereof is embedded is obtained. Then, thermistor element 2 of Examples 1-8 was manufactured by baking for 2 hours at 1500 ° C. in the atmosphere. The thermistor elements according to Comparative Examples 1 and 2 were manufactured in the same manner.
Each dimension of the thermistor element 2 is a hexagonal shape with a side of 1.15 mm, a thickness of 1.00 mm, a diameter φ0.3 mm of the electrode wires 2a and 2b, an electrode center distance of 0.74 mm (gap 0.44 mm), and an electrode insertion amount 1.10 mm.

Next, for the thermistor elements of Examples 1 to 8, the B constant (temperature gradient constant) was measured as follows. That is, first, the thermistor element 2 was left in an environment of T (−40) = 233 K (= −40 ° C.), and the initial resistance value R (−40) of the thermistor element 2 in that state was measured. Next, the thermistor element 2 was left in an environment of T (900) = 1173K (= 900 ° C.), and the initial resistance value R (900) of the thermistor element 2 in that state was measured. And B constant: B (-40-900) was computed according to the following formula | equation (1).
B (-40 ~ 900) = ln [R (900) / R (-40)] / [1 / T (900) -1 / T (-40)] (1)
R (-40): resistance value (kΩ) of the thermistor element at −40 ° C., R (900): resistance value (kΩ) of the thermistor element at 900 ° C.

Further, the thermistor element 2 according to the third embodiment is incorporated in the temperature sensor 100 as described later, and the initial resistance values R (-40) and R (900) of the thermistor element 2 in the state of the temperature sensor 100 are measured. did. Next, the temperature was maintained at 1050 ° C. × 50 Hr in the atmosphere, and then the resistance values R ′ (− 40) and R ′ (900) after the heat treatment of the thermistor element at −40 ° C. and 900 ° C. were measured in the same manner as described above. . Then, from the comparison between the initial resistance value R (−40) at −40 ° C. and the post-heat treatment resistance value R ′ (− 40), the temperature change converted value CT (−40) of the resistance change due to the heat treatment (unit: deg ) Was calculated by the following formula (2). From the comparison between the initial resistance value R (900) at 900 ° C. and the post-heat treatment resistance value R ′ (900), the temperature change conversion value CT (900) was calculated by the same equation (3). In addition, the larger one of the temperature change converted values CT (-40) and CT (900) is shown in Table 1 as the temperature change converted value CT (deg).
CT (-40) = [(B (-40 ~ 900) × T (-40)) / [ln (R '(-40) / R (-40)) × T (-40) + B (-40 ~ 900)]]-T (-40) (2)
CT (900) = [(B (-40 to 900) × T (900)) / [ln (R '(900) / R (900)) × T (900) + B (-40 to 900)]] -T (900) (3)
Note that, in the temperature sensor 100, an oxide film is formed in advance on the inner peripheral surface of the metal tube 3 and the metal outer cylinder constituting the sheath member 8. Thereby, even when the vicinity of the thermistor element 2 of the temperature sensor 100 is set to a high temperature, oxidation of the outer tube of the metal tube 3 and the sheath 8 is suppressed, and the atmosphere in the metal tube 3 is prevented from becoming a reducing atmosphere. ing. Therefore, the sensor element 2 is prevented from being reduced and its resistance value is changed.

Furthermore, with respect to the thermistor element 2 (single unit) according to each of the examples and the comparative example, the resistance change when the temperature change was repeatedly applied was evaluated. Specifically, it is cooled from room temperature (25 ° C.) to −40 ° C. at a temperature decrease rate of −80 deg / Hr, and left at −40 ° C. for 2.5 hours, and the resistance value R1 (−40) of the thermistor element is taking measurement. Thereafter, the temperature is increased to 900 ° C. at a temperature increase rate of +300 deg / Hr, maintained at 900 ° C. for 2 hours, and the resistance value R1 (900) is measured. Next, the temperature is cooled again to −40 ° C. at a temperature drop rate of −80 deg / Hr, maintained at −40 ° C. for 2.5 hours, and the resistance value R 2 (−40) of the thermistor element is measured. Thereafter, the temperature is further increased to 900 ° C. at a temperature increase rate of +300 deg / Hr, maintained at 900 ° C. for 2 hours, and the resistance value R2 (900) is measured.
Based on the comparison between the resistance value R1 (-40) and resistance value R2 (-40) at -40 ° C, the temperature change conversion value DT (-40) (unit: deg) It was calculated by the following formula (4). Further, from the comparison between the resistance value R1 (900) and the resistance value R2 (900) at 900 ° C., the temperature change converted value DT (900) was calculated by the same equation (5). The larger one of the temperature change converted values DT (-40) and DT (900) is shown in Table 1 as the temperature change converted value DT (deg).
DT (-40) = [(B (-40 ~ 900) x T (-40)) / [ln (R2 (-40) / R1 (-40)) x T (-40) + B (-40 ~ 900)]] − T (-40) (4)
DT (900) = [(B (-40 to 900) × T (900)) / [ln (R2 (900) / R1 (900)) × T (900) + B (-40 to 900)]] − T (900) ... (5)
These results are shown in Table 1.

According to Table 1, the conductive oxide sintered body 1 having the compositions of Examples 1 to 8 in which the values a, b, c, d, e, and f of the composition formula YaSrbMncAldCreOf satisfy the following conditional expressions. In the used thermistor element 2, the B constant: B (−40 to 900) is B (−40 to 900) = 2000 to 3000 K, which is a relatively low value compared to the conventional conductive oxide sintered body. 1 (thermistor element 2). The thermistor element 2 using such a conductive oxide sintered body 1 has an appropriate resistance value over a wide range from a low temperature of −40 ° C. to a high temperature of 900 ° C., and can perform temperature measurement appropriately. It becomes.
Although the value f is not described in Table 1, it is in the range of f = 2.80 to 3.30 from the composition ratio of each element of Y, Sr, Mn, Al, Cr, O using fluorescent X-ray analysis. I have confirmed that. The same applies to the conductive oxide sintered body 1 (thermistor element 2) in Examples 9 to 17 described later.
0.600 ≦ a ≦ 1.000
0 ≦ b ≦ 0.400
0.150 ≦ c <0.600
0.400 ≦ d ≦ 0.800
0 <e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.80 ≦ f ≦ 3.30

In Example 8, the thermistor element 2 using the conductive oxide sintered body 1 containing no Sr was shown. However, in addition to Y, the conductive oxide sintered body 1 containing Sr (thermistor element 2). Is preferably used.
That is, as shown in Examples 1 to 7, it is preferable that a <1.000, b> 0. In the sintered body 1 according to Example 8 that does not contain Sr (2A group element M2), when a large number of this sintered body 1 (thermistor element 2) is manufactured, characteristic variation and firing among the individual bodies There is a tendency that characteristic variation between lots tends to increase. In comparison with this, for example, in the sintered body 1 of Examples 1 to 7 containing Sr (2A group element M2) in addition to Y (3A group element M1), the characteristic variation among individuals is relatively large. And variations in characteristics between firing lots can be reduced.

  The range of the B constant is preferably B (-40 to 900) = 2000 to 2900K, and more preferably B (-40 to 900) = 2000 to 2800K. .

On the other hand, as can be seen from Comparative Examples 1 and 2, when the value is out of the range of the present invention, the B constant: B (−40 to 900) is out of the range of B (−40 to 900) = 2000 to 3000K. I understand that. Specifically, in the case of Comparative Example 1 where the value of d exceeds the range of the above conditional expression (d ≦ 0.800), and the value of e / (c + e) is within the range of the above conditional expression (e / It can be seen that the B constant exceeds 3000K in any case of Comparative Example 2 exceeding (c + e) ≦ 0.18). In this case, the resistance change of the thermistor element in the temperature range of −40 ° C. to 900 ° C. becomes too large, making it difficult to measure appropriate resistance over the entire temperature range, making it difficult to measure temperature appropriately. Become.
Although not shown as a comparative example, depending on the composition (for example, when d indicating the molar ratio of Al is below the range of the conditional expression (d ≧ 0.400)), the B constant is 2000K. May fall below. In this case, the resistance change of the thermistor element becomes too small, and resistance measurement over the entire temperature range of −40 ° C. to 900 ° C. is possible. Temperature measurement becomes difficult.
Note that Comparative Example 2 in Table 1 corresponds to that shown as Example 20 in Patent Document 2.

Furthermore, in the thermistor element 2 using the conductive oxide sintered body 1 of Example 3, the temperature change converted value CT (deg) was +5 deg. A standard for determining whether or not the sintered body 1 (thermistor element 2) has a characteristic that the resistance change with respect to the thermal history is small is considered that the temperature change conversion value CT is ± 10 deg. The sintered body 1 (thermistor element 2) of Example 3 is included in the range of this guideline, exhibits a high temperature durability with good temperature characteristics that is comparable to the sintered body of Comparative Example 2, and has a thermal history. It turns out that it becomes the sintered compact 1 with a small resistance change with respect to, and the thermistor element 2 using this.
In addition, about the sintered compact of other Examples 1, 2, 4-8, the measurement result of temperature change conversion value CT is not specified.

However, the temperature change conversion value DT measured by the above-described method is measured for any of the examples and comparative examples. In any of the examples, the temperature change conversion value DT was ± 0 deg.
The temperature change conversion value DT is ± 10 deg as a guideline for determining whether or not the sintered body 1 (thermistor element 2) has the characteristic that the resistance change with respect to the thermal history is small even with this temperature change conversion value DT. it is conceivable that. The sintered bodies 1 (thermistor elements 2) of Examples 1 to 8 are included in the range of this guideline, and the thermistor elements 2 of Examples 1 to 8 all have a small resistance change with respect to thermal history. It turns out that it is a sintered body (thermistor element) which can be used practically without any problem. In particular, in all of Examples 1 to 7, since the temperature change conversion value DT was ± 0 deg., Particularly in the elements and composition ratios used in Examples 1 to 7, resistance change with respect to a good thermal history, It turns out that it has the high temperature durability of a temperature characteristic.

  Next, the configuration of the temperature sensor 100 using the thermistor element 2 according to the present embodiment will be described with reference to FIG. The temperature sensor 100 uses the thermistor element 2 as a temperature sensing element. The temperature sensor 100 is mounted on a mounting portion of an exhaust pipe of an automobile, and the thermistor element 2 is disposed in an exhaust pipe through which exhaust gas flows. It is used for detecting the temperature of exhaust gas.

  In the temperature sensor 100, the metal tube 3 extending in the direction along the axis (hereinafter also referred to as the axial direction) has a bottomed cylindrical shape with the tip 31 side (downward in FIG. 2) closed. The thermistor element 2 of this embodiment is housed inside the portion 31. This metal tube 3 is heat-treated in advance, and the outer side surface and the inner side surface thereof are oxidized and covered with an oxide film. Cement 10 is filled around the thermistor element 2 inside the metal tube 3 to fix the thermistor element 2. The rear end 32 of the metal tube 3 is open, and the rear end 32 portion is press-fitted and inserted into the flange member 4.

  The flange member 4 is positioned on the distal end side (downward in FIG. 2) of the cylindrical sheath portion 42 extending in the axial direction, and has a larger outer diameter than the sheath portion 42 and has a radial direction. And a flange portion 41 protruding outward. On the distal end side of the flange portion 41, there is a tapered seating surface 45 that performs sealing with the attachment portion of the exhaust pipe. Moreover, the sheath part 42 has comprised the two-stage shape which consists of the front end side sheath part 44 located in the front end side, and the rear end side sheath part 43 smaller in diameter than this.

  The metal tube 3 press-fitted into the flange member 4 is firmly fixed to the flange 4 by laser welding of the outer peripheral surface of the metal tube 3 at the portion L1 over the entire circumference in the circumferential direction. Yes. Moreover, the substantially cylindrical metal cover member 6 is press-fitted into the distal end side sheath portion 44 of the flange member 4, and is laser-welded at the portion L2 over the entire circumference in the circumferential direction and joined in an airtight state.

  Further, a mounting member 5 having a hexagonal nut portion 51 and a screw portion 52 is rotatably fitted around the flange member 4 and the metal cover member 6. The temperature sensor 100 of the present embodiment is configured so that the seat surface 45 of the flange portion 41 of the flange member 4 is brought into contact with the attachment portion of the exhaust pipe (not shown) and the nut 5 is screwed into the attachment portion, thereby Fix it.

Inside the metal tube 3, the flange member 4, and the metal cover member 6, a sheath member 8 that includes a pair of core wires 7 is disposed. The sheath member 8 includes a metal outer tube, a pair of conductive core wires 7, and an insulating powder that fills the outer tube and holds the core wire 7 while insulating between the outer tube and each core wire 7. It is configured. Note that an oxide film is also formed in advance on the outer cylinder of the sheath 8 by heat treatment. The electrode wires 2a and 2b of the thermistor element 2 are connected by laser welding to the core wire 7 protruding from the tip of the outer cylinder of the sheath member 8 inside the metal tube 3 (downward in the figure).
On the other hand, the core wire 7 protruding from the sheath member 8 toward the rear end side is connected to a pair of lead wires 12 via a crimping terminal 11. The core wires 7 and the crimping terminals 11 are insulated from each other by an insulating tube 15.

  The pair of lead wires 12 are drawn out from the inside of the metal cover member 6 to the outside through the lead wire insertion holes of the elastic seal member 13 inserted inside the rear end portion of the metal cover member 6, (It is not shown. For example, it is connected to the terminal member of the connector 21 for connecting with ECU.). As a result, the output of the thermistor element 2 is taken out from the core wire 7 of the sheath member 8 to the external circuit (not shown) via the lead wire 12 and the connector 21, and the temperature of the exhaust gas is detected. The lead wire 12 is covered with a glass braided tube 20 for protection from external forces such as stepping stones, and the glass braided tube 20 is fixed by crimping to the metal cover member 6 with its elastic end member 13 together with the elastic seal member 13. Has been.

  In the temperature sensor 100 having such a structure, since the thermistor element 2 made of the conductive oxide sintered body 1 is used, the exhaust gas temperature of the automobile engine is set to 900 ° C. from a low temperature of −40 ° C. The temperature sensor can measure the temperature appropriately over a wide area up to a high temperature.

Example 9
Then, using Nd ₂ O ₃ , SrCO ₃ , Fe ₂ O ₃ , Al ₂ O ₃ , Cr ₂ O ₃ (all commercially available products with a purity of 99% or more), the chemical formula (composition formula) NdaSrbFecAldCreO ₃ a , B, c, d, e are the thermistor elements 2 using the conductive oxide sintered body 1 having the number of moles shown in Example 9 of Table 2, and the measurement results of B (-40 to 900) are shown. It is shown in 2.
The thermistor element 2 using the conductive oxide sintered body 1 having the composition shown in Example 9 is also produced in the same manner as in Example 1 described above except that the raw materials are different. The measurement method for B (-40 to 900) is also the same.

According to Table 2, in the thermistor element 2 using the conductive oxide sintered body 1 of Example 9, the B constant is similarly B (−40 to 900) = 2000 to 3000K, specifically , B (−40 to 900) = 2740K. Therefore, the thermistor element 2 using such a conductive oxide sintered body 1 has an appropriate resistance value over a wide range from a low temperature of −40 ° C. to a high temperature of 900 ° C., and appropriately measures the temperature. Is possible.
In addition, although the measurement result of the temperature change converted value CT is not clearly shown for Example 9, the temperature change converted value DT is DT = −10 deg, which is within ± 10 deg which is the above-mentioned standard. From this, it can be seen that the sintered body 1 (thermistor element 2) of Example 9 is also a sintered body (thermistor element) that has a small resistance change with respect to the thermal history and can be used practically without any problem.

(Examples 10 and 11)
Furthermore, using Y ₂ O ₃ , SrCO ₃ , CaCO ₃ , MnO ₂ , Al ₂ O ₃ , Cr ₂ O ₃ (all commercially available products with a purity of 99% or more) were used, the chemical formula (composition formula) YaSrb ₁ Cab _2. About the thermistor element 2 using the conductive oxide sintered body 1 in which a, b (= b1 + b2), c, d, e when MncAldCreO ₃ is used are the number of moles shown in Examples 10 and 11 of Table 3. , B (−40 to 900), and the measurement result of the temperature change converted value CT are shown in Table 3.
The thermistor element 2 using the conductive oxide sintered body 1 having the composition shown in Examples 10 and 11 is also produced in the same manner as Example 1 described above except that the raw materials are different. Further, the measurement method of B (−40 to 900) and the temperature change converted value CT is the same as described above.

  According to Table 3, also in the thermistor element 2 using the conductive oxide sintered bodies 1 of Examples 10 and 11, the B constant is B (−40 to 900) = 2000 to 3000K, specifically It can be seen that B (−40 to 900) = 2913 K (Example 10) or 2814 K (Example 11) can be obtained. Therefore, the thermistor element 2 using such a conductive oxide sintered body 1 has an appropriate resistance value over a wide range from a low temperature of −40 ° C. to a high temperature of 900 ° C., and appropriately measures the temperature. Is possible.

Furthermore, it can be seen that the sintered body (thermistor element) of Example 10 has a temperature change conversion value CT = ± 5 deg and has high temperature durability with good temperature characteristics equivalent to Example 3. Similarly, the temperature change conversion value DT was a good value of DT = ± 0 deg.
In addition, although the measurement result of specific temperature change conversion value CT is not specified, about temperature change conversion value DT, it is DT = ± 0deg and the sintered compact 1 (thermistor element 2) of Example 11 is also It can be seen that this is a sintered body (thermistor element) that has a small resistance change with respect to the thermal history as in Example 10 and can be used practically without problems.

(Examples 12 to 14)
Furthermore, using Y ₂ O ₃ , SrCO ₃ , MgO, MnO ₂ , Al ₂ O ₃ , Cr ₂ O ₃ (all commercial products with a purity of 99% or more were used), the chemical formula (composition formula) YaSrb ₁ Mgb ₂ MncAldCreO About the thermistor element 2 using the conductive oxide sintered body 1 in which a, b (= b1 + b2), c, d, e when ₃ is set to the number of moles shown in Examples 12 to 14 of Table 4, Table 4 shows the measurement results of B (-40 to 900).
The thermistor element 2 using the conductive oxide sintered body 1 having the composition shown in Examples 12 to 14 is also produced in the same manner as in Example 1 described above except that the raw materials are different. The measurement method for B (-40 to 900) is the same as described above.

  According to Table 4, also in the thermistor element 2 using the conductive oxide sintered bodies 1 of Examples 12 to 14, the B constant is B (-40 to 900) = 2000 to 3000K, specifically It can be seen that B (−40 to 900) = 2950K (Example 12), 2920K (Example 13), or 2688K (Example 14). Therefore, the thermistor element 2 using such a conductive oxide sintered body 1 has an appropriate resistance value over a wide range from a low temperature of −40 ° C. to a high temperature of 900 ° C., and appropriately measures the temperature. Is possible.

  In Examples 12 to 14, the specific measurement result of the temperature change converted value CT is not clearly shown, but the temperature change converted value DT is DT = + 10 deg in Examples 12 and 13, and Example 14 Then, DT = + 8 deg, which is within ± 10 deg which is the above-mentioned standard. From this, it can be understood that the sintered bodies 1 (thermistor elements 2) of Examples 12 to 14 are also small sintered bodies (thermistor elements) that can be used practically without any problem in resistance change with respect to the thermal history.

(Examples 15 to 17)
Furthermore, using Y ₂ O ₃ , Yb ₂ O ₃ , SrCO ₃ , MnO ₂ , Al ₂ O ₃ , Cr ₂ O ₃ (all commercially available products with a purity of 99% or more were used), chemical formula (composition formula) A thermistor element using the conductive oxide sintered body 1 in which a (= a1 + a2), b, c, d, e in the case of Ya1Yba ₂ SrbMncAldCreO ₃ has the number of moles shown in Examples 15 to 17 in Table 5 Table 5 shows the measurement results for B (−40 to 900).
The thermistor element 2 using the conductive oxide sintered body 1 having the composition shown in Examples 15 to 17 is also produced in the same manner as Example 1 described above except that the raw materials are different. The measurement method for B (-40 to 900) is the same as described above.

  According to Table 5, also in the thermistor element 2 using the conductive oxide sintered bodies 1 of Examples 15 to 17, the B constant is B (-40 to 900) = 2000 to 3000K, specifically It can be seen that B (−40 to 900) = 2734K (Example 15), 2401K (Example 16), or 2438K (Example 17). Therefore, the thermistor element 2 using such a conductive oxide sintered body 1 has an appropriate resistance value over a wide range from a low temperature of −40 ° C. to a high temperature of 900 ° C., and appropriately measures the temperature. Is possible.

  In Examples 15 to 17, the specific measurement result of the temperature change converted value CT is not clearly shown, but the temperature change converted value DT is DT = ± 0 in Example 15 and DT in Example 16. = + 5 deg, and in Example 17, DT = + 8 deg, which is within ± 10 deg which is the above-mentioned standard. From this, it can be understood that the sintered bodies 1 (thermistor elements 2) of Examples 15 to 17 are also sintered bodies (thermistor elements) that have a small resistance change with respect to thermal history and can be used practically without problems.

In the above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, the thermistor element 2 according to Examples 9 to 17 can also be applied to the temperature sensor 100 (see FIG. 2), whereby the temperature of the exhaust gas of the automobile engine is reduced from a low temperature of −40 ° C. to 900 ° C. A temperature sensor capable of appropriately measuring the temperature over a wide range up to a high temperature of ° C. can be obtained.
In the production of the conductive oxide sintered body (thermistor element), as the raw material powder, a powder of a compound containing each element exemplified in each example can be used. In addition, compounds such as oxides, carbonates, hydroxides, and nitrates can be used. In particular, oxides and carbonates are preferably used.

  In addition, when required for conductive oxide sintered bodies, thermistor elements, or temperature sensors, such as the sinterability of conductive oxide sintered bodies, the B constant, and the high temperature durability of temperature characteristics, the characteristics are not impaired. The conductive oxide sintered body may contain other components such as Na, K, Ga, Si, C, Cl, and S.

It is explanatory drawing which shows the shape of the thermistor element which concerns on a present Example. It is a fragmentary sectional view which shows the structure of the temperature sensor using the thermistor element of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive oxide sintered body 2 Thermistor element 2a, 2b Electrode wire 100 Temperature sensor

Claims (6)

One or more elements selected from Y, Nd, and Yb are defined as M1,
One or more elements selected from Mg, Ca, Sr is M2,
When one or more elements selected from Mn and Fe are M3,
Is expressed by the composition formula _{M1 a M2 b M3 c Al d} Cr e O f, a conductive sintered oxide that have a perovskite crystal structure,
A conductive oxide sintered body in which a, b, c, d, e, and f satisfy the following conditional expression.
0.600 ≦ a ≦ 1.000
0 ≦ b ≦ 0.400
0.150 ≦ c <0.600
0.400 ≦ d ≦ 0.800
0.005 ≦ e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.80 ≦ f ≦ 3.30 The conductive oxide sintered body according to claim 1,
A conductive oxide sintered body in which a and b satisfy the following conditional expression.
0.600 ≦ a <1.000
0 <b ≦ 0.400 The conductive oxide sintered body according to claim 2,
A conductive oxide sintered body in which a, b, c, d, e, and f satisfy the following conditional expression.
0.820 ≦ a ≦ 0.950
0.050 ≦ b ≦ 0.180
0.181 ≦ c ≦ 0.585
0.410 ≦ d ≦ 0.790
0.005 ≦ e ≦ 0.050
0 <e / (c + e) ≦ 0.18
2.91 ≦ f ≦ 3.27 The conductive oxide sintered body according to any one of claims 1 to 3 , wherein
The element M1 is Y;
The element M2 is Sr;
A conductive oxide sintered body in which M3 is Mn. The thermistor element which uses the electroconductive oxide sintered compact of any one of Claims 1-4 . A temperature sensor using the thermistor element according to claim 5 .

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