JPH08273904A - Thermistor material and its manufacture - Google Patents

Abstract

PURPOSE: To obtain a thermistor material which has a wide temperature region and which is excellent in the linearity of a temperature-resistance change by a method wherein a semiconductor or a conductive substance whose coefficient of thermal expansion is different from that of the matrix of an insulating substance is dispersed discontinuously into the matrix and a dispersed material forms an electric network. CONSTITUTION: SiC in 15wt.% and that in 20wt.% whose particle size ratio (SiO3 N4 /SiC) are added to an Si3 N4 power in 79wt.% and that in 74wt.% and a Y2 O3 power in 6wt.% so as to be wet-mixed and dried, and a granulated powder is formed. The granulated powder is pressed and molded, it is hot-pressed and sintered under conditions of 18 to 50 deg.C, in a nitrogen air current and for one hour, and composite materials A1 (addition amount of SiC: 20wt.%) and A2 (addition amount of SiC: 15wt.%) are obtained. When their surface is observed under a metal microscope, the circumference of Si3 N4 matrix crystal particles is surrounded by SiC particles, and the SiC particles are dispersed discontinuously in a three-dimensional mesh shape into a base material. In the composite materials A1 , A2 , their temperature-resistance characteristic displays a linear relationship in a wide range from room temperature up to 1000 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermistor material and a manufacturing method thereof, and more particularly to a thermistor material having a wide temperature measuring range and a manufacturing method thereof.

[0002]

2. Description of the Related Art A thermistor material is a material that serves as a resistor whose resistance value changes sensitively with temperature and is used in various temperature sensors and the like. This thermistor material is used for temperature sensors for cooking devices such as microwave ovens and electric kettles, temperature sensors for air conditioning and heating such as air conditioners and fan heaters, temperature sensors for health and beauty devices such as electronic thermometers and hot water toilet bowls, and refrigerators. Temperature sensors for home appliances other than the above, such as clocks and watches, temperature sensors for various OA equipment, temperature sensors for automobiles used for air intake temperature detection, engine temperature measurement, cooling water temperature detection, tobacco leaf drying, ice machine, seawater temperature measurement For industrial use, vending machines, refrigeration showcases, and other industrial temperature sensors, various temperature sensors for inspections, etc., ranging from home appliances to industrial, physics and chemistry research, medical / communication, and space development. . Further, this thermistor material can be used as a hot thermistor for a special purpose, for example, as a humidity sensor, a wind speed sensor, or the like. Further, active development of applied equipment using these thermistor materials as the detection unit is also active, and absolute temperature measurement using temperature measuring equipment such as temperature controllers and temperature recorders and absolute humidity sensors using thermistor materials as humidity detection elements. In addition to humidity measurement equipment such as a hygrometer, dew point meter, dew condensation control controller, humidity controller, and water activity meter, wind speed, flow velocity,
The thermistor material has a wide range of applications, such as the possibility of detecting the degree of vacuum, gas concentration, etc., and the development of composite equipment that combines these.

However, the temperature sensor using the conventional thermistor material has a limited operating temperature range. For example, at low temperatures (about -30 ° C to 300 ° C), Mn, C
O, Ni, Fe-based oxides for medium temperature (200 ℃ ~ 80
In about 0 ℃), Mn-NiO-Cr 2 O 3 -Zr
O ₃ , SiC, MgAl ₂ O ₄ -Cr ₂ O ₃ system, etc.
ZrO ₂ − for high temperatures (700 ° C to 1200 ° C)
_{Y 2 O 3, MgO-Al} 2 O 3 -Cr 2 O 3 -Fe 2 O
_{When three} systems are used and the temperature measuring range is wide, there is a problem that it is necessary to use a plurality of thermistor temperature sensors having different temperature measuring regions together.

In order to solve these problems of the prior art, the thermistor element body contains 30 to 99.99% by weight of NiO,
A "high temperature thermistor" (Japanese Unexamined Patent Publication No. 6-163206) composed of a NiO-MgO composite oxide composed of 01 to 70 wt% MgO has been proposed. Thereby, a resistance value changing region can be obtained over a wide temperature range, the resistance value and the B constant can be freely changed over a wide range, and a high temperature thermistor having excellent DC load life characteristics at high temperature can be provided. I am going to do it.

Further, (Mn.Cr) O ₄ spinel having a high resistance value and a high resistance temperature coefficient and Y showing a low resistance temperature coefficient.
A high temperature thermistor capable of varying the resistance value and the temperature coefficient of resistance in a wide range by appropriately mixing CrO ₃ and CrO ₃ to obtain a sintered body.
No. 2805) has been proposed. As a result, it is possible to provide a high temperature thermistor material with a wide range of choices for the resistance value and the temperature coefficient of resistance.

Further, in an organic positive temperature coefficient thermistor composed of two kinds of resin or rubber phase forming a sea-island structure and a conductive substance dispersed therein, adjacent islands are adjacent to each other at low temperature. The organic positive temperature coefficient thermistor is made of a resin or rubber that has a compatibility with the above-mentioned electroconductive substance and can form a completely separated island at high temperature. (Japanese Patent Laid-Open No. 5
-47505 gazette) is proposed. As a result, the thermistor of the present invention has a wide range of choices for the matrix and the conductive substance, so that it is possible to prepare the thermistor having characteristics suitable for each purpose of use, and further, the resistance change rate is large and the change with time is small. It is said that there are many advantages such that the switching temperature can be selected in a wide range.

Further, by forming a composition having a three-dimensional continuous micro-mesh structure of carbon short fibers having an average length of 0.005 to 1 mm and a diameter of 3 to 20 μm in a crystalline polymer matrix, an energized path chain is formed. "Positive temperature coefficient composition and production method" (Japanese Patent Laid-Open No. 62-4750) for efficiently carrying out the process have been proposed. It is stated that this makes it possible to provide a polymer composition having excellent PTC characteristics. It also states that the amount of short carbon fibers to be used may be small and the polymer composition can be produced at low cost.

Further, in a sintered ceramic comprising a ceramic phase selected from an insulating ceramic phase, a semiconductor ceramic phase and a mixture thereof, and a conductive material phase which is at least partially continuous, the ceramic phase is at least 30 μm. A "conductive composite ceramics" (Japanese Patent Publication No. 60-18081) has been proposed which is composed of aggregates having the following particle sizes. As a result, not only the non-linearity but also the linearity and desired positive and negative temperature characteristics can be obtained by selecting the types of both materials to be composited and their ratios, and also obtaining the desired conductivity. It is supposed to be possible.

[0009]

However, the high temperature thermistor disclosed in Japanese Patent Laid-Open No. 6-163206 has the following problems.
Since MgO is simply mixed as an insulator in the NiO matrix of the conductor to increase the resistance value, the temperature-resistance characteristics strongly depend on the characteristics of NiO itself, and the resistance value R with respect to the temperature T is the same as the conventional one. It has a problem that it changes according to a different exponential function and does not reach a linear relationship. In addition, a large amount of MgO needs to be added to control the resistance value and B constant, and there is a problem in that efficiency is lacking.

The high temperature thermistor disclosed in Japanese Unexamined Patent Publication No. 5-62805 has the same problem as the high temperature thermistor disclosed in Japanese Unexamined Patent Publication No. 6-163206.

Further, in the organic positive temperature coefficient thermistor described in JP-A-5-47505, the conductive material is uniformly dispersed in the island portion, and the island portion is also uniformly dispersed in the sea portion. However, there is a problem that the structure is such that a sudden decrease in resistance, that is, only switching appears with contact of the island portion, and a uniform decrease in resistance does not easily occur.

Further, in the positive temperature coefficient composition and manufacturing method described in JP-A-62-4750, a continuous carbon short fiber is used.
Since the three-dimensional network structure is formed, the temperature resistance characteristics are determined by the thermoelectric characteristics of carbon, which makes it difficult to control the resistance change with temperature.
Moreover, since the polymer and the carbon fiber are used, 30
It cannot be used in a high temperature range of 0 ° C. or higher, and has a problem that the temperature measurement range is narrow.

Further, in the conductive composite ceramics disclosed in Japanese Patent Publication No. 60-18081, since the conductive material is composed of aggregates having a continuous phase partially or wholly, temperature-resistance characteristics are added. However, there is a problem that it is difficult to obtain a linear resistance change with respect to temperature because the conductive material is strongly dependent on its characteristics.

Therefore, the inventors of the present invention have earnestly studied to solve the above-mentioned problems of the prior art, and as a result of various systematic experiments, the present invention has been accomplished.

(Object of the Invention) An object of the present invention is to provide a thermistor material having a wide temperature measurement range and excellent linearity in temperature-resistance change, and a method for producing the thermistor material.

The present inventors have focused their attention on the following problems of the prior art. That is, when the second phase conductive material is continuously dispersed in the matrix as the first phase, the temperature-resistance characteristic of the conductive material largely controls the temperature-resistance characteristic of the thermistor material. . It is necessary to form conductive paths in the matrix in order to obtain a uniform decrease in resistance value due to temperature rise. However, when a mesh structure with continuous conductive paths is formed, the temperature-resistance value relationship of the conductive material is increased. It is difficult to obtain a linear resistance value characteristic. Therefore, attention has been paid to the fact that the conductive material having a particle size smaller than that of the matrix crystal grains forms paths in a three-dimensional network and the paths are discontinuous at intervals within a predetermined range. The coefficient of thermal expansion of the conductive material is different from that of the matrix (larger or /
And a small value), the composite material having the above structure is used to make use of the uniform decrease in the conductive interval due to the difference in thermal expansion between the matrix and the dispersion material at the time of temperature increase, thereby making a linear resistance value. It has been found that the properties are expressed.

[0017]

[Means for Solving the Problems]

(Structure of First Invention) A thermistor material of the present invention comprises a matrix made of a substance having an insulating property, and a dispersant made of a substance having a coefficient of thermal expansion different from that of the matrix discontinuously dispersed in the matrix. In the thermistor material, the dispersant comprises a semiconductor substance or a substance having electrical conductivity, and the dispersant dispersed in the matrix discontinuously forms a network-like electrical path structure in the thermistor material. It is characterized by being formed.

(Structure of the Second Invention) The thermistor material of the present invention comprises a matrix made of a substance having an insulating property, and a three-dimensional mesh-like structure in which the matrix is continuously dispersed.
A third phase consisting of a substance having a coefficient of thermal expansion different from that of the matrix and relaxing the internal stress caused by the difference in thermal expansion, and the matrix and the thermal expansion dispersed discontinuously in the third phase. Dispersing material consisting of substances with different rates,
Wherein the dispersant is a semiconductor substance or a substance having electrical conductivity, and the dispersant dispersed in the third phase is discontinuous in a three-dimensional network in the thermistor material. It is characterized by forming a network-like electrical path structure by being dispersed in the.

(Structure of Third Aspect) The method for producing a thermistor material according to the present invention comprises a matrix raw material powder made of a substance having an insulating property, a semiconductor substance having a coefficient of thermal expansion different from that of the matrix raw material powder, or a substance having an electrical conductivity. Consists of
And a raw material powder preparation step of mixing a raw material powder having a size of 1/2 or less of the matrix raw material powder, a molding step of shaping the raw material powder into a predetermined shape to obtain a shaped body, By heating, a composite material is formed which comprises a matrix made of a substance having an insulating property and a dispersant made of a substance having a different coefficient of thermal expansion from the matrix dispersed discontinuously in the matrix in a three-dimensional mesh form. And a composite material forming step.

(Structure of Fourth Aspect) According to the method for producing a thermistor material of the present invention, a semiconductor material or a conductive material having a different coefficient of thermal expansion from the matrix material powder is provided on the surface of the matrix material powder made of an insulating material. And a dispersant material powder having a size equal to or less than 1/2 of the matrix material powder, and having a coefficient of thermal expansion closer to that of the matrix material powder than the coefficient of thermal expansion of the dispersant material powder. A raw material powder preparation step of mixing so as to sprinkle with a third phase raw material made of a substance that relaxes internal stress caused by a difference in thermal expansion of the dispersion material formed by the dispersion raw material powder at the time of temperature measurement; Molding step of molding into a predetermined shape to obtain a molded body, heating the molded body to form a matrix made of an insulating material, and a three-dimensional mesh in the matrix. And a third phase consisting of a substance having a different coefficient of thermal expansion from the matrix and relaxing the internal stress caused by the difference in thermal expansion, and discontinuously dispersed in the third phase. And a composite material forming step of forming a composite material comprising the matrix and a dispersion material made of a substance having a different coefficient of thermal expansion.

[0021]

The mechanism by which the thermistor material and the method for producing the same according to the present invention can provide a thermistor material having a wide temperature measurement range and excellent linearity in temperature-resistance change is not clear yet. Can be thought of as.

(Operation of First Invention) The thermistor material of the present invention comprises a matrix made of an insulating substance,
A dispersant made of a substance having a coefficient of thermal expansion different from that of the matrix is discontinuously dispersed. Moreover, the dispersion material is made of a semiconductor material or a material having electrical conductivity, and the dispersion material discontinuously dispersed in the matrix forms a network-like path structure in the thermistor material. . In this thermistor material, the dispersant having a different coefficient of thermal expansion from the matrix is discontinuously dispersed in a three-dimensional network form. The dispersant spacing is uniformly reduced or increased. At this time, since the thermal expansion during heating increases / decreases in proportion to the temperature regardless of the temperature range, the change in the spacing of the dispersant due to the difference in thermal expansion becomes linear regardless of the temperature range. it is conceivable that. Since the electric resistance value decreases or increases in proportion to the distance between the adjacent dispersants, it does not depend on the temperature-resistance characteristics of the dispersant as in the past, and has a linear temperature-resistance characteristic over a wide temperature range. It is believed that you can get

From the above, the thermistor material of the present invention is
It is considered to have a wide temperature measurement range and excellent linearity in temperature-resistance change.

(Operation of Second Invention) The thermistor material of the present invention comprises a matrix made of a substance having an insulating property, and a three-dimensional mesh-like structure in which the matrix is continuously dispersed.
A third phase consisting of a substance having a coefficient of thermal expansion different from that of the matrix and relaxing the internal stress caused by the difference in thermal expansion, and the matrix and the thermal expansion dispersed discontinuously in the third phase. Dispersing material consisting of substances with different rates,
Wherein the dispersant is a semiconductor substance or a substance having electrical conductivity, and the dispersant dispersed in the third phase is discontinuous in a three-dimensional network in the thermistor material. It is characterized by forming a network-like electrical path structure by being dispersed in the. In this thermistor material, the dispersant having a coefficient of thermal expansion different from that of the matrix is discontinuously dispersed in the thermistor material in a three-dimensional mesh, so that when the present thermistor material is heated,
The difference in thermal expansion between the matrix and the dispersant uniformly reduces or increases the spacing between adjacent dispersants. At this time, since the thermal expansion during heating increases / decreases in proportion to the temperature regardless of the temperature range, the change in the distance between the dispersants due to the difference in thermal expansion is linear regardless of the temperature range. Conceivable. Since the electric resistance value decreases or increases in proportion to the distance between the adjacent dispersants, it does not depend on the temperature-resistance characteristics of the dispersant as in the past, and has a linear temperature-resistance characteristic over a wide temperature range. It is believed that you can get In addition, the thermistor material of the present invention is a third phase composed of a substance which has a coefficient of thermal expansion different from that of the matrix and which relaxes internal stress caused by a difference in thermal expansion in the matrix made of a substance having an insulating property. Are continuously dispersed in a three-dimensional mesh. As a result, the internal stress (thermal stress) caused by the difference in thermal expansion can be relaxed, and the generation, propagation and destruction of cracks can be suppressed.

From the above, the thermistor material of the present invention is
It is considered to have a wide temperature measurement range, excellent linearity in temperature-resistance change, and excellent mechanical properties.

(Operation of Third Invention) In the method for producing a thermistor material of the present invention, first, in the raw material powder preparing step, the matrix raw material powder made of a substance having an insulating property and the coefficient of thermal expansion of the matrix raw material powder are different from each other. It is made of a semiconductor material or a substance having electrical conductivity, and its size (size of granulated powder in the case of granulated powder) is 1/2 of matrix raw material powder (size of granulated powder in the case of granulated powder) The following dispersant raw material powder is mixed. Next, in the molding step, the raw material powder obtained in the raw material powder preparation step is molded into a predetermined shape to obtain a molded body.

Here, the size of the dispersant raw material powder used in the raw material powder preparation step is 1/2 or less of the size of the matrix raw material powder. At this time, when using the granulated powder, the size of the granulated powder is 1/2 or less. By using the dispersant raw material powder having a size in this range,
There is an advantage that the dispersant can easily form a three-dimensional network structure surrounding the plurality of matrix crystal grains. When the size of the dispersant raw material powder exceeds 1/2 of the size of the matrix raw material powder, the dispersant is randomly dispersed in the matrix.

Next, in the composite material forming step, when the formed body obtained in the forming step is heated, the matrix becomes a liquid phase at a predetermined temperature or higher, and the crystal grains precipitate and grow. Move (or eject) and rearrange into a mesh. Thereby, a composite material comprising a matrix made of a substance having an insulating property and a dispersant made of a substance having a different (larger or smaller) coefficient of thermal expansion from the matrix dispersed discontinuously in the matrix in a three-dimensional mesh shape. Can be formed.

From the above, it is considered that a thermistor material having a wide temperature measuring range and excellent linearity in temperature-resistance change can be easily obtained.

(Operation of Fourth Aspect) In the method for producing a thermistor material of the present invention, first, in the raw material powder preparation step, the matrix raw material powder (including granulated powder) made of a substance having an insulating property is formed on the surface of the matrix raw material powder. A matrix material powder having a coefficient of thermal expansion different from that of the matrix material powder or a material having conductivity and having a size of 1/2 or less of that of the matrix material powder; The matrix raw material has a coefficient of thermal expansion close to that of the raw material powder and relaxes internal stress caused by the difference in thermal expansion of the dispersion material formed by the dispersion material raw material powder during temperature measurement. 1 / powder
Mix by sprinkling with no more than 2 third phase source materials. The amount of addition is such that the amount of the third phase raw material is larger than that of the dispersant raw material powder. Next, in the molding step, the raw material powder obtained in the raw material powder adjusting step is molded into a predetermined shape to obtain a molded body.

Here, the sizes of the dispersant raw material powder and the third phase raw material used in the raw material powder preparation step (including the sizes of the respective granulated powder and mixed powder) are 1 / the size of the matrix raw material powder. The size is 2 or less. By using a material having a size within this range, the third phase raw material is in a mixed state of surrounding the matrix raw material powder, and after sintering, a continuous three-dimensional network surrounding a plurality of matrix crystal grains in the composite material. It becomes possible to form a structure. Further, the raw material powder for the dispersant material is in a mixed state in which the periphery of the raw material powder for the matrix is discontinuously surrounded, and after sintering, it is discontinuously dispersed in the third phase dispersed in a continuous three-dimensional network in the composite material. be able to. If this size is larger than 1/2 of the matrix raw material powder, the third phase raw material is surrounded by the dispersant, and is mixed randomly with the matrix raw material powder. The three phases are randomly dispersed in the matrix, and the dispersant forms a microstructure in which they are dispersed in a three-dimensional network around them. on the other hand,
The dispersant raw material powder was mixed with the matrix raw material powder in a random state in a state where the third-phase raw material was sprinkled around it, and after sintering, the matrix and the dispersant were randomly dispersed. Since the microstructure is formed, the desired thermistor material cannot be formed.

Next, in the composite material forming step, when the formed body obtained in the forming step is heated, the third phase becomes a liquid phase at a temperature equal to or higher than a predetermined temperature to disperse as the crystal grains precipitate and grow. The material migrates (or drains) and the dispersed material rearranges in a mesh within the third phase. As a result, a matrix made of a substance having an insulating property and a coefficient of thermal expansion closer to that of the matrix than the coefficient of thermal expansion of the dispersant dispersed in the matrix in a three-dimensional mesh shape are provided. And a third phase consisting of a substance that relaxes internal stress due to a difference in thermal expansion and a dispersion consisting of a substance having a different thermal expansion coefficient from the matrix dispersed discontinuously in the third phase. It is possible to form a composite material including a material.

From the above, it is considered that a thermistor material having a wide temperature measuring range and excellent linearity in temperature-resistance change can be easily obtained without deteriorating the mechanical strength characteristics of the matrix.

[0034]

【The invention's effect】

(Effect of the first invention) The thermistor material of the first invention has a wide temperature measuring range and excellent linearity in temperature-resistance change.

(Effect of the Second Invention) The thermistor material of the second invention has a wide temperature measuring range and excellent linearity in temperature-resistance change. Also, this thermistor material has excellent mechanical properties.

(Effect of the third invention) By the method for manufacturing a thermistor material according to the second invention, a thermistor material having a wide temperature measuring range and excellent linearity of temperature-resistance change can be easily obtained.

(Effect of Fourth Invention) By the method for producing a thermistor material of the fourth invention, the temperature measurement range is wide and the linearity of temperature-resistance change is excellent without deteriorating the mechanical characteristics of the matrix. The thermistor material can be easily obtained.

[0038]

EXAMPLES The thermistor material of the present invention and the method for producing the thermistor will be described below with respect to more specific inventions, limited inventions and other inventions (other inventions).

<Description of Other Inventions>

(Matrix) The matrix is made of an insulating material. Specifically, mullite, silica, sialon, silicon nitride, alumina, zircon, cordierite, boron nitride, chromium oxide, titanium oxide, boron oxide, molybdenum oxide, hafnium oxide, yttria,
Ytterbium oxide, niobium oxide, tungsten oxide,
Lanthanum oxide, magnesia, steatite, forsterite, sillimanite, spinel, aluminum titanate, aluminum zirconate, NiO, V ₂ O ₅ , Mo
O ₃ , WO _{3 and the} like can be mentioned.

(Dispersion Material) The dispersion material is made of a semiconductor material or a material having electrical conductivity, which has a coefficient of thermal expansion different from that of the matrix. Specifically, TiB ₂ , TiB, Ti
₂ B ₅ , ZrB ₂ , ZrB ₁₂ , V ₃ B ₂ , VB, V ₅ B
₆ , V ₂ B ₃ , VB ₂ , Nb ₃ B ₂ , NbB, Nb ₃ B
₄ , Nb ₆ B ₂ , Ta ₂ B, Ta ₃ B ₂ , TaB, Ta
₃ B ₄ , TaB ₂ , Cr ₂ B, Cr ₅ B ₃ , CrB, C
r ₃ B ₄ , CrB ₂ , MoB, Mo ₂ B, MoB ₂ , M
o ₂ B ₅ , MoB ₁₂ , W ₂ B, WB, W ₂ B ₅ , W
_{B 2, HfB, LaB 6,} TiC, ZrC, VC, Nb
C, TaC, Cr ₃ C ₂ , Mo ₂ C, W ₂ C, WC, T
iN, ZrN, VN, NbN, TaN, Cr ₂ N, Si
_{C, TiSi 2, ZrSi 2,} TaSi 2, CrS
i ₂ , Mo ₅ Si ₃ , MoSi ₂ , WSi ₂ , Cr ₂ O
₃ , ZrO ₂ , ReO ₃ , RaO ₂ , LaTiO ₃ , C
aMnO ₃ , LaMnO ₃ , CaCrO ₃ , NiFeO
₃ , SrCrO ₃ , Ca ₂ O, ZnO, CaO, Mn
O, and the like.

Here, in the thermistor material of the present invention, the matrix is preferably one or more ceramics selected from oxides, nitrides, and silicides. Thereby, not only the linear temperature-resistance characteristic can be expressed by adjusting the interval of the dispersion material, but also the rate of change of resistance due to temperature change can be controlled.

In the thermistor material of the present invention,
The dispersant is preferably one or more ceramics selected from carbides, silicides, nitrides, borides, and oxides. As a result, a conductive path with high heat resistance can be formed.
The thermistor material can be made highly reliable in a wide range up to the above high temperature range.

(Dispersion Form of Dispersing Material) The dispersing material is discontinuously dispersed in the matrix and has a network-like electrical path structure formed in the matrix.

Here, in the thermistor material of the present invention, it is preferable that the dispersant has a network structure so as to surround a plurality of crystal grains of the substance constituting the matrix. Thereby, the characteristics of the dispersant can be sufficiently exhibited with a small amount of addition.

In the thermistor material of the present invention,
It is preferable that the dispersant is dispersed in the thermistor material in a three-dimensional mesh shape in a discontinuous manner. Thereby, the resistance can be adjusted by both the electric resistance characteristic of the dispersion material itself and the proportional resistance due to the particle spacing, and the electric resistance peculiar to the composite obtained by combining them can be expressed.

The first preferred thermistor material of the present invention is
A first phase forming a matrix made of an insulating material, and formed so as to discontinuously surround the first phase,
A thermistor material cell consisting of the first phase and a second phase as a dispersant composed of a semiconductor substance having a different coefficient of thermal expansion or a substance having electrical conductivity is used as a constituent unit, and the dispersant is a three-dimensional mesh in the thermistor material. It is a thermistor material characterized in that it is dispersed in a discontinuous shape and that the dispersion material forms a network-like electrical path structure in the thermistor material.

3 to 6 are explanatory views conceptually showing a concrete example of the structure of the thermistor material cell.

3 and 4 are schematic explanatory views of a cross section of a specific example of the thermistor material cell. FIG. 3 shows the first phase 3
Is an example of a polycrystalline material, and the thermistor material cell 2 constitutes the first phase 3 with a plurality of crystal grains 31 as one block, and the dispersant 41 surrounds the second phase discontinuously to form the second phase.
It is a structure in which phase 4 is formed.

FIG. 4 shows an example of a material in which the first phase 3 is made of an amorphous or single crystalline substance such as resin. A disk-shaped or a deformed mass of a predetermined size is made into one block and a dispersion material is used. 41 has a structure in which the second phase 4 is formed by surrounding it discontinuously.

FIGS. 5 and 6 are explanatory views conceptually showing specific examples of the thermistor material cells. FIG. 5 shows the dispersion material 41 around the entire circumference of the spherical or elliptical first phase 3 block.
Has a structure in which the second phase is formed by being surrounded discontinuously.

FIG. 6 shows a structure in which the second phase 4 is formed so that the dispersant 41 is discontinuously dispersed over the entire circumference of the columnar or oblong first phase 3.

The state of "discontinuously dispersed in a three-dimensional mesh" means that the dispersion material is a single substance and / or an aggregate of the single substances (forms that are partially connected or The state of being in contact with each other) is a state in which the thermistor material is arranged in a three-dimensional network. When the matrix is composed of crystal grains, one mesh refers to a matrix formed around several matrix crystal grains as one unit. Preferably, the number of particles that are continuously connected is small, and the discontinuous phase composed of a dispersant is dispersed at minute intervals. More preferably, 0.005
The dispersed particles are arranged at intervals of about several μm. It should be noted that the dispersion form of the dispersion material may be one that forms a mesh structure in a basically discontinuous state as described above, and the shape of one mesh is a polygon, a circle, or an ellipse. , Or an irregular shape. Further, in the dispersant, particles may be partially continuously dispersed or may form a continuous body as long as the action and effect of the present invention are not impaired.

In the thermistor material of the present invention, it is preferable that the distance between the dispersants is 10 μm or less. As a result, even if the dispersion material is discontinuous, it is possible to develop electrical conductivity with a predetermined resistance value. In addition, it is more preferable that the interval of the dispersion material is 0.005 μm to 1 μm.

In the thermistor material of the present invention,
The size of the dispersion material is preferably 0.01 μm to 100 μm. This facilitates formation of the three-dimensional network structure (conductive path) of the dispersant in the thermistor material composite without increasing the particle size of the matrix powder. Moreover, since the particle size of the matrix powder can be reduced, high sinterability can be secured. Also, if the particle size is too small, the dispersant does not form a complete continuous network. The size of the dispersion material is 0.01 μm or more.
More preferably, it is 1 μm.

In the thermistor material of the present invention,
One size (for example, the size of the cell) of the network structure formed by disperse the dispersant discontinuously,
It is preferably 0.1 μm to 500 μm. As a result, the strength of the thermistor material cell is less likely to decrease due to peeling or the like at the outer peripheral portion thereof, and the second phase characteristics can be sufficiently exhibited with a small amount of the dispersing material. It is more preferable that one size of the network structure is 0.5 μm to 50 μm. In addition, it is preferable that the resistance change can be greatly changed by changing the width and size of the cell.

In the thermistor material of the present invention,
One size of the network structure formed by disperse | distributing the said dispersion material is 5 times-5 * 10 < ⁴ > of the said dispersion material.
It is preferably double. As a result, a predetermined amount of the dispersant can be dispersed around the plurality of matrix crystal grains at a predetermined interval, and electric conductivity can be exhibited. In addition, one size of the network structure is equal to that of the dispersion material.
It is more preferably 0 to 1000 times.

In the thermistor material of the present invention,
It is preferable that the dispersant has a size not larger than 1/3 of the size of the crystal grains of the substance forming the matrix, and is discontinuously dispersed in a three-dimensional mesh. As a result, the particles of the matrix, the fibers, or the like can be reinforced by the dispersion material. The size of the dispersant is 1/1000 to 1 / the size of the crystal grains of the substance forming the matrix.
4 is more preferable.

In the thermistor material of the present invention,
The presence ratio of the dispersant is preferably in the range of 2 to 50% by weight. If the proportion is less than 2% by weight, the spacing between the dispersants becomes large, and it may be difficult to achieve the effect of the skeletal structure and the functionality. On the other hand, if it exceeds 50% by weight, the density of the mesh-like dispersed phase and the dispersant in the reinforcing layer becomes high, so that the sinterability may be lowered and the strength may be lowered. The ratio is 10
It is more preferable for it to be in the range of from 40 to 40% by weight, since the effects of the present invention can be better exhibited.

In the thermistor material of the present invention,
It is preferable that the third phase that alleviates internal stress caused by thermal expansion is dispersed in the matrix together with the dispersant in a discontinuous and meshed manner. As a result, it is possible to suppress the repeated fatigue fracture and the generation of minute cracks due to the internal stress generated during temperature measurement.

As the substance constituting the third phase, a material having a low Young's modulus capable of relaxing the internal stress caused by the difference in thermal expansion, or easily deformable, or a material having a high strength and not generating a microcrack due to the internal stress. Is preferred. Specifically, a substance having a small elastic modulus, a substance that easily undergoes crystal phase transformation, a substance having micropores, or the like is used. Furthermore, a material that is well compatible with the base material and has a high insulating property or at least an electric resistance lower than that of the dispersion material is preferable.

A second suitable thermistor material of the present invention is
A matrix made of a substance having an insulating property, and a reinforcing layer having an insulating property made of a substance which is the same as or similar to the matrix and which is continuously dispersed in a three-dimensional network in the matrix (by adding a dispersant of the thermistor material, A third phase as a layer for suppressing the strength reduction or a layer for strengthening), and a dispersion comprising a semiconductor material or a material having conductivity which is discontinuously dispersed in the reinforcing layer and has a coefficient of thermal expansion different from that of the matrix. A thermistor material comprising a material, wherein the dispersion material is three-dimensionally meshed and discontinuously dispersed in the thermistor material, and the dispersion material has a mesh-like electrical path structure in the thermistor material. It is a thermistor material characterized by being formed.

In the second preferred thermistor material of the present invention, the form of existence of the third phase (reinforcing layer) in the matrix is continuously dispersed in a three-dimensional network in the matrix (that is, the first phase). The three phases are continuously dispersed in a three-dimensional network in the thermistor material). Specifically, as shown in FIG. 8, an example thereof is a thermistor material cell (cellular unit) in which a matrix 3 is separated by a third phase 5.
2 is one unit, and the third phase 5 is continuously dispersed in a matrix in a three-dimensional network, and the dispersant is discontinuously dispersed in the third phase. In this case,
The third phase dispersed in a three-dimensional network can strongly bond the matrices. Furthermore, it is possible to adjust the electric resistance between the dispersion materials.

In the second preferred thermistor material of the present invention, another specific existing form is a form in which the matrix 3 and the third phase 5 are both formed into a continuous three-dimensional network as shown in FIG. Is. In the case of this form, there is an advantage that not only the characteristics of the third phase 5 but also the characteristics of the matrix 3 itself can be expressed more strongly.

In the second preferred thermistor material of the present invention, another specific mode of existence is a mode in which the third phase 5 dispersed in a two-dimensional network is laminated, as shown in FIG. In the case of this form, it is possible to provide anisotropy that strongly exhibits characteristics in the two-dimensional direction (plane direction). In particular, there is an advantage that it is effective in the case of a thin plate.

In the second preferred thermistor material of the present invention, the more preferred third phase is continuously dispersed in the thermistor material in a three-dimensional network and comprises the same or similar substance as the matrix, The size D of one mesh in the portion formed by the third phase and the dispersion material is 1 μm ≦
The structure is within a range of D ≦ 1000 μm, and the portion forms a path in a three-dimensional mesh shape. In the case of this structure, both the substance and the dispersant that are the same as or similar to the matrix mixed in the third phase can be strongly bound together by the grain boundary phase, and at the same time, the first of the three-dimensional network structure constituted by them can be formed. A unique effect that the three-phase effect can be strongly exerted can be achieved.

In the second preferred thermistor material of the present invention, the dispersion form of the dispersant in the third phase (reinforcing layer) is
A form in which the dispersant is uniformly (randomly) dispersed in the reinforcing layer, a form in which the dispersant is unevenly dispersed in the reinforcing layer,
There is a form in which the dispersion material is regularly dispersed in a specific form such as a mesh or a layer in the reinforcing layer. Further, at this time, the unit of the dispersant dispersed in the third phase is (a) even if it is an individual such as one particle or whisker, (b) the part of the individual (the part consisting of the minimum constitutional unit) Even if the individuals are mixed with the connected or aggregated portions to form a discontinuous portion, (c) the individual is connected or aggregated to form a discontinuous portion, Any combination of these may be used. In this case, the dispersant forming the group may be one kind or plural kinds of dispersants having different intended electric resistance characteristics.

In the second preferred thermistor material of the present invention, the dispersion form of the dispersant in the third phase is specifically
As shown in FIG. 11, the dispersion material 41 is randomly dispersed throughout the third phase 5. In the case of this form, since the dispersant 41 can be held individually (minimum unit) by the third phase 5 made of the same substance as the matrix 3 or a substance similar to the matrix (residual stress distribution is uniform), high immediate breaking strength is obtained. And the high impact resistance and the repeated fatigue resistance can be obtained.

In the second preferred thermistor material of the present invention, as another specific dispersion form of the dispersant, as shown in FIG. 12, the dispersant 41 in the third phase 5 has a discontinuous network structure ( (Including partially discontinuous) is a dispersed form. In the case of this form, the strength is somewhat lower than that in the case where the dispersion material 41 is randomly dispersed, but the dispersion material 4
1 has the advantage that the functional properties such as the electrical properties and the thermal properties of 1 can be strongly expressed.

In the second preferred thermistor material of the present invention, another specific dispersion form of the dispersant is that the dispersant 41 inhibits the sintering of the matrix 3 and the third phase 5, as shown in FIG. It is in a state of being closely distributed in the range not to be. In the case of this form, the strength is somewhat lower than in the case where the dispersant is randomly dispersed, but there is an advantage that high electrical conductivity (low resistance) can be exhibited. Further, in the low thermal expansion dispersion material, it is possible to exhibit the PTC effect in which the electric resistance increases linearly with the temperature rise.

In the second preferred thermistor material of the present invention, another specific dispersion form of the dispersion material is as shown in FIG. 14, in which the dispersion material 41 partially continuous in the circumferential direction is dispersed in a layer form. It is a form. In the case of this embodiment, the strength is slightly lower than that in the case where the dispersant is randomly dispersed, but higher electrical conductivity is obtained with a smaller amount of the dispersant 41 (than the specific example of FIG. 13). It has the advantage that it can be expressed strongly.

In the second preferred thermistor material of the present invention, another specific dispersion form of the dispersant is a form in which two or more dispersants having different characteristics are dispersed in the circumferential direction of the matrix particles. As shown in FIG. 15, the first dispersion material 4
There is a mode in which it is composed of two layers of No. 2 and the second dispersion material 43. In the case of this form, there is an advantage that it is possible to impart the characteristics of a plurality of dispersion materials.

In the second preferred thermistor material of the present invention, another specific dispersion form of the dispersant is a form dispersed in both the third phase 5 and the matrix as shown in FIG. . In the case of this form, the matrix 3
The dispersion material 41 (as an additive) dispersed in the third phase 5
The characteristics may be the same as or different from those of the dispersion material 41 therein, and further, a plurality of additives having various characteristics may be dispersed.

In the second preferred thermistor material of the present invention, the dispersant is discontinuously dispersed in the third phase and is also discontinuously dispersed in the thermistor material in a three-dimensional network. Become. Here, “three-dimensionally meshed and discontinuously dispersed” means that as shown in FIG.
1 refers to a state in which 1s are separated or partially connected (contacted) in the thermistor material and arranged in a three-dimensional mesh pattern.

In the second preferred thermistor material of the present invention, when the matrix is composed of crystal grains, one mesh is a unit 32 composed of several or more matrix crystal grains 12 as shown in FIG. A unit consisting of a matrix crystal grain and a part of the third phase formed around the crystal grain is defined as a unit, and the dispersion material forms a mesh skeleton around the unit. Preferred is a form in which few particles are continuously connected and the discontinuous phase is dispersed at minute intervals. More preferably, it is a form in which each dispersed grain is connected through a grain boundary phase of submicron (0.

In the second preferred thermistor material, the third phase is replaced with "the third phase as an insulating reinforcing phase composed of a substance which is the same as or similar to the matrix", and "the heat of the dispersion material is used." In the case of the third phase as a relaxation layer composed of a substance having a coefficient of thermal expansion closer to that of the matrix than that of the matrix and relaxing the internal stress due to the difference in thermal expansion, Distributed form similar to,
The existence form and structure can be adopted. At this time, the third phase as the relaxation layer is composed of a substance having a small elastic modulus, a substance which easily undergoes crystal phase transformation, a substance having micropores, and the like.

(Preferable Thermistor Material Manufacturing Method) A preferable thermistor material manufacturing method of the present invention is: a matrix raw material powder made of an insulating material; and a thermal expansion coefficient larger than that of the matrix raw material powder Is a raw material powder preparation step of mixing ½ or less of the matrix raw material powder with a dispersant raw material powder, a molding step of shaping the raw material powder into a predetermined shape to obtain a shaped body, and heating the shaped body. ,
Composite material formation for forming a composite material comprising a matrix made of a material having an insulating property and a dispersant made of a substance having a coefficient of thermal expansion higher than that of the matrix and discontinuously dispersed in the matrix in a three-dimensional mesh And a process.

In this preferred manufacturing method, first, in a raw material powder preparation step, a matrix raw material powder made of an insulating material and a matrix raw material powder having a coefficient of thermal expansion larger than that of the matrix raw material powder / 2 or less dispersant raw material powder is mixed. At this time,
Even when the raw material powder is a granulated powder, the ratio is in the above range.
Next, in the molding step, the raw material powder obtained in the raw material powder preparation step is molded into a predetermined shape to obtain a molded body.

Next, in the composite material forming step, when the formed body obtained in the forming step is heated, the dispersant moves (or is discharged) as the matrix crystallizes and grows at a predetermined temperature or higher, Rearrange in a mesh pattern. This makes it possible to form a composite material including a matrix made of an insulating material and a dispersant made of a substance having a thermal expansion coefficient larger than that of the matrix dispersed in the matrix discontinuously in a three-dimensional network. it can.

As a result, it is possible to form a structure in which the distance between the dispersants dispersed in a three-dimensional mesh shape and discontinuously becomes narrow (or widens) in proportion to the temperature rise. Therefore, it is considered that a thermistor material having a wide temperature measurement range and excellent linearity in temperature-resistance change can be easily obtained.

Here, in the raw material powder adjusting step of the method for producing a thermistor material of the present invention, a dispersant having a coefficient of thermal expansion larger than that of the matrix is discontinuously formed on the surface of the granulated powder having a predetermined shape as the main material of the matrix. It is preferable that the raw material powder is prepared as it is present. As a result, a discontinuous three-dimensional network structure can be formed around the plurality of matrix crystal grains in the sintered body. In this case, it is preferable that the size of the dispersion material is a size that does not cause a large decrease in strength.

(Suitable Method for Producing Thermistor Material) In another preferred method for producing the thermistor material of the present invention, the coefficient of thermal expansion is different from that of the matrix raw material powder on the surface of the matrix raw material powder made of an insulating material. Dispersant raw material powder composed of a semiconductor material or a substance having electrical conductivity and having a size of 1/2 or less of the matrix raw material powder, and a thermal expansion coefficient closer to that of the matrix raw material powder than the thermal expansion coefficient of the dispersion raw material powder. A third material having a coefficient of expansion and relaxing internal stress caused by a difference in thermal expansion of the dispersion material formed by the dispersion material powder during temperature measurement, and having a size of 1/2 or less of the matrix material powder. A raw material powder preparation step of mixing the phase raw material with a powder, and a molding step of molding the raw material powder into a predetermined shape to obtain a molded body,
The molded body is heated to form a matrix composed of a substance having an insulating property, and the matrix is continuously dispersed in a three-dimensional network in the matrix. Form a composite material consisting of a third phase consisting of a substance that relaxes this when it occurs, and a dispersant dispersed in the third phase and consisting of a substance having a different coefficient of thermal expansion from the matrix And a composite material forming step.

As a result, a matrix made of an insulating material and a coefficient of thermal expansion closer to that of the matrix than the coefficient of thermal expansion of the dispersant dispersed in the matrix in a three-dimensional network form are obtained. A third phase consisting of a substance that has an internal stress that relaxes internal stress due to a difference in thermal expansion, and a substance that has a coefficient of thermal expansion different from that of the matrix dispersed discontinuously in the third phase. A dispersant consisting of a semiconductor material or a substance having conductivity, wherein the dispersant dispersed discontinuously in the third phase is three-dimensional in the thermistor material. A thermistor material having a network-like discontinuous dispersion and a network-like electrical path structure formed therein can be easily manufactured.

At this time, in the raw material powder adjusting step, the dispersant raw material powder and the third phase raw material are mixed or granulated in advance to form an additional raw material powder, and then the additional raw material powder is sprinkled on the surface of the matrix raw material powder. Is more preferable. Thereby, desired mixing can be easily performed. The third-phase raw material is composed of a material having a small elastic modulus, a material that easily undergoes crystal phase transformation, a material having micropores, and the like.

(Suitable Method for Producing Thermistor Material) In another preferred method for producing the thermistor material of the present invention, the coefficient of thermal expansion is different from that of the matrix raw material powder on the surface of the matrix raw material powder made of an insulating substance. It is composed of a semiconductor material or a material having electrical conductivity, and a dispersant raw material powder having a size equal to or less than 1/2 of the matrix raw material powder, and a material which is the same as the matrix raw material powder or close to the matrix raw material powder. A raw material powder preparation step of mixing with ½ or less of a matrix raw material powder of a third phase raw material, a molding step of shaping the raw material powder into a predetermined shape to obtain a shaped body, and the shaped body And a matrix composed of a substance having an insulating property, and the matrix, which is continuously dispersed in a three-dimensional network in the matrix. A third phase as a reinforcing layer having an insulating property consisting of one or a similar substance, and a semiconductor substance or a substance having a conductivity which is discontinuously dispersed in the third phase and has a coefficient of thermal expansion different from that of the matrix. And a composite material forming step of forming a composite material including the dispersion material.

As a result, a matrix made of an insulating material and a reinforcing layer having an insulating property made of the same or similar material as the matrix, which is continuously dispersed in a three-dimensional network in the matrix, are formed. A thermistor material comprising a third phase and a dispersant which is discontinuously dispersed in the reinforcing layer and which is made of a semiconductor material having a different coefficient of thermal expansion from the matrix or a material having electrical conductivity, the dispersant being To easily produce a thermistor material in which the thermistor material is three-dimensionally meshed and discontinuously dispersed, and the dispersion material forms a network-like electric path structure in the thermistor material. You can

At this time, in the raw material powder adjusting step, the dispersant raw material powder and the third phase raw material are mixed or granulated in advance to form an additional raw material powder, and then the additional raw material powder is sprinkled on the surface of the matrix raw material powder. Is more preferable. Thereby, desired mixing can be easily performed. The third-phase raw material is composed of a material having a small elastic modulus, a material that easily undergoes crystal phase transformation, a material having micropores, and the like.

EXAMPLES Examples of the present invention will be described below.

First Example First, 79% by weight and 74% by weight of Si ₃ N ₄ powder (average primary particle diameter: 0.2 μm) and 6% by weight of Y ₂ O ₃
Powder (average primary particle size: 0.5 μm), particle size ratio (S
15 wt% and 20 wt% of SiC having i ₃ N ₄ / SiC of 6 to 7 was added, wet-mixed with a ball mill, dried and spray-dried to produce granulated powder.

The obtained granulated powder was placed in a mold and uniaxially press-molded (pressure: 20 MPa), and then 1850 ° C. × 1.
Hot-press sintering was performed under conditions of time (in N ₂ ) to obtain a composite material according to this example (sample number: 1 [SiC addition amount: 20% by weight]), sample number: 2 [SiC addition amount: 15% by weight]. ]).

A cross section of the obtained composite material was subjected to ECR plasma etching, and the surface thereof was observed with a metallographic microscope. As a result, in the composite material of this example, the SiC particles surround a plurality of Si ₃ N ₄ (matrix) crystal grains,
Moreover, it was confirmed that the SiC particles were discontinuously dispersed in a three-dimensional network in the base material.

Second Example 82% by weight of Si ₃ N ₄ powder having an average primary particle size of 0.1 μm
And 5% by weight of Y ₂ O ₃ powder having an average primary particle diameter of 0.5 μm,
And 3% by weight of Al ₂ O ₃ powder having an average primary particle diameter of 0.1 μm are wet mixed in a ball mill to give a particle diameter of several tens of μm.
A base material raw material granulated powder of ˜300 μm was produced.

Next, on the surface of the base material granulated powder, an average of 1
SiC particles having a secondary particle diameter of 0.4 μm were sprinkled so as to be 10% by weight and discontinuously scattered to obtain a raw material powder.

Next, this raw material powder was put into a mold, press-molded, further subjected to CIP treatment (3 t / cm ² ), and then 185
Pressure sintering was carried out at 0 ° C. for 4 hours under N ₂ pressure of 10 kg / cm ² to obtain a composite material of the present invention according to this example (Sample No. 3).

The cross section of the obtained composite material was subjected to plasma etching, and the particle structure of the cross section was observed by SEM (scanning electron microscope). As a result, it was confirmed that the dispersant was dispersed discontinuously in the matrix in a three-dimensional mesh shape.

Comparative Example 1 For comparison, 82% by weight of Si ₃ N ₄ powder (average primary particle diameter 0.3 μm), 5% by weight of Y ₂ O ₃ powder (average primary particle diameter 1 μm) and average primary particle diameter were used. Al with a particle size of 0.1 μm
₂ O ₃ powder 3% by weight and 10% by weight average primary particle diameter of 0.
Wet-mix 4 μm SiC powder with a ball mill at the same time to prepare granulated powder (average particle size 500 μm or less) in which SiC particles are uniformly dispersed in the matrix, and otherwise the same as in the second embodiment. Molding and pressure sintering were performed under the conditions of (Sample No. C1). Observation of the cross section of this comparative sintered body revealed that SiC was found in the Si ₃ N ₄ matrix.
The particles were uniformly dispersed.

Comparative Example 2 For comparison, 70% by volume of SiO ₂ powder (average primary particle diameter of 1.2 μm) and 30% by volume of SiC particles having a SiO ₂ / SiC particle size ratio of about 1 / 1.5 were used. The granulated powder prepared by wet mixing with a ball mill was put into a mold and press-molded, and then hot press-sintered under the condition of 1800 ° C. × 1 hour and 20 MPa to obtain a comparative sintered body. (Sample number: C
2). When the cross section of the obtained comparative sintered body was observed,
It was observed that the SiC particles were randomly dispersed in the matrix SiO ₂ .

Comparative Example 3 For comparison, a sintered body (sample number: C3) made of only Si ₃ N _{4 in} which SiC was not dispersed was prepared.

Comparative Example 4 For comparison, a sintered body made of only SiC (sample number: C
4) was prepared.

Comparative Example 5 For comparison, a commercially available sintered body made of a MgO—Al ₂ O ₃ —Cr ₂ O ₃ type thermistor material was prepared (sample number: C5).

Performance Evaluation Test With respect to the composite materials obtained in the first and second examples and the comparative sintered bodies obtained in Comparative Examples 1 to 5, the temperature range from room temperature to 1000 ° C. The electric resistance value (4 contact method) was measured. The results are shown in FIG. 1 and FIG.
And shown in Table 1.

[0102]

[Table 1]

As is clear from FIGS. 1 and 2 and Table 1, the sintered bodies of the first and second examples have temperature-resistance characteristics in a wide range from room temperature to 1000 ° C. It can be seen that there is a linear relationship. Furthermore, it was also possible to control the rate of change in resistance value with respect to temperature rise by adjusting the particle size ratio between the average particle size of the primary particles or granulated powder of the matrix and the dispersant. In contrast,
A comparative sintered body in which SiC is uniformly dispersed (sample number: C
1), the Si ₃ N ₄ sintered body (sample number: C3), and the commercially available MgO—Al ₂ O ₃ —Cr ₂ O ₃ system sintered body have a logarithmic decrease in the electrical resistance value as the temperature rises. However, the comparative sintered body (sample number: C2) in which SiC is randomly dispersed has a curve-temperature-resistance characteristic, and the SiC sintered body (sample number: C4) has an electric resistance value of around 400 ° C. Has been stabilized since. As described above, it is understood that it is difficult to obtain a linear temperature-resistance value characteristic in any of the comparative sintered bodies.

[Brief description of drawings]

FIG. 1 is a diagram showing the temperature-resistance value characteristics of the composite materials obtained in the first and second examples of the present invention and the sintered bodies of Comparative Example 1, Comparative Example 4, and Comparative Example 5. is there.

FIG. 2 is a diagram showing temperature-resistance value characteristics of a comparative sintered body obtained in Comparative Example 2.

FIG. 3 is an explanatory view conceptually explaining a specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 4 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 5 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 6 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 7 is an explanatory view conceptually explaining a specific example of a three-dimensional mesh-like discontinuous dispersion structure of the thermistor material of the present invention.

FIG. 8 is an explanatory view conceptually showing a specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 9 is an explanatory view conceptually showing another specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 10 is an explanatory view conceptually showing another specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 11 is an explanatory view conceptually showing a specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 12 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 13 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 14 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 15 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 15 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 16 is a diagram showing a dispersion form of a specific example of the dispersion material of the thermistor material of the present invention, and an explanatory view conceptually showing a form of “discontinuously dispersed in a three-dimensional mesh”.

FIG. 17 is an explanatory view conceptually explaining a specific example of a mesh forming the thermistor material of the present invention.

FIG. 18 is an explanatory view conceptually explaining a specific example of a microstructure that constitutes the thermistor material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermistor material 2 ... Thermistor material cell 3 ... Matrix (1st phase) 31 ... Matrix constituent substance 4 ... 2nd phase 41 ... Dispersion material 5 ... 3rd phase (In some cases, a reinforcing layer) 6 ... Additive A1 ... Sample number: 1 (first example) A2 ... Sample number: 2 (first example) A3 ... Sample number: 3 ( 2nd Example) C1 ... Sample number: C1 (Comparative example 1) C2 ... Sample number: C2 (Comparative example 2) C3 ... Sample number: C3 (Comparative example 3) C4 ... Sample number : C4 (Comparative Example 4) C5 ... Sample No .: C5 (Comparative Example 5)

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 3, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a diagram showing the temperature-resistance value characteristics of the composite materials obtained in the first and second examples of the present invention and the sintered bodies of Comparative Example 1, Comparative Example 4, and Comparative Example 5. is there.

FIG. 2 is a diagram showing temperature-resistance value characteristics of a comparative sintered body obtained in Comparative Example 2.

FIG. 3 is an explanatory view conceptually explaining a specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 4 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 5 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 6 is an explanatory view conceptually explaining another specific example of the thermistor material cell of the thermistor material of the present invention.

FIG. 7 is an explanatory view conceptually explaining a specific example of a three-dimensional mesh-like discontinuous dispersion structure of the thermistor material of the present invention.

FIG. 8 is an explanatory view conceptually showing a specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 9 is an explanatory view conceptually showing another specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 10 is an explanatory view conceptually showing another specific example of the existence form of the third phase (strengthening layer and / or relaxation layer) of the thermistor material of the present invention.

FIG. 11 is an explanatory view conceptually showing a specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 12 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 13 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 14 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 15 is an explanatory view conceptually showing another specific example of the dispersion form of the dispersion material of the thermistor material of the present invention.

FIG. 16 is a view showing a dispersion form of a specific example of the dispersant of the thermistor material of the present invention, and an explanatory view conceptually showing a form of “discontinuously dispersed in a three-dimensional mesh form”.

FIG. 17 is an explanatory view conceptually explaining a specific example of a mesh forming the thermistor material of the present invention.

FIG. 18 is an explanatory view conceptually explaining a specific example of a microstructure that constitutes the thermistor material of the present invention.

[Explanation of Codes] 1 ... Thermistor material 2 ... Thermistor material cell 3 ... Matrix (first phase) 31 ... Matrix constituent substance 4 ... Second phase 41 ... Dispersion material 5. ..Third phase (reinforcement layer in some cases) 6 ... Additive A1 ... Sample number: 1 (first example) A2 ... Sample number: 2 (first example) A3 ... Sample number: 3 (second example) C1 ... Sample number: C1 (Comparative example 1) C2 ... Sample number: C2 (Comparative example 2) C3 ... Sample number: C3 (Comparative example 3) C4・ ・ ・ Sample number: C4 (Comparative example 4) C5 ・ ・ ・ Sample number: C5 (Comparative example 5)

Claims (17)

[Claims] 1. A thermistor material comprising a matrix made of an insulating material and a dispersant dispersed in the matrix discontinuously made of a material having a coefficient of thermal expansion different from that of the matrix. The material is made of a semiconductor material or a material having electrical conductivity, and the dispersion material discontinuously dispersed in the matrix forms a network-like electrical path structure in the thermistor material. Thermistor material. 2. The thermistor material according to claim 1, wherein the dispersion material forms a network structure so as to surround a plurality of crystal grains of a substance forming a matrix. 3. The thermistor material according to claim 2, wherein the dispersant is discontinuously dispersed in the thermistor material in a three-dimensional mesh shape. 4. The thermistor material according to claim 1, wherein the spacing between the dispersants is 10 μm or less. 5. The thermistor material according to claim 1, wherein the dispersion material has a size of 0.01 μm to 100 μm. 6. The thermistor material according to claim 2, wherein one size of the network structure formed by disperse the dispersant material is 0.1 μm to 500 μm. . 7. The thermistor material according to claim 6, wherein the size of one of the network structures formed by disperse the dispersant is two to 5 × 1 times that of the dispersant.
A thermistor material characterized by being 0 ⁴ times. 8. The thermistor material according to claim 1, wherein the matrix is one or more ceramics selected from oxides, nitrides, and silicides. 9. The thermistor material according to claim 1, wherein the dispersant is one or more ceramics selected from carbides, silicides, nitrides, borides, and oxides. 10. The thermistor material according to claim 1, wherein the dispersant has a size equal to or less than 1/3 of the size of the crystal grains of the substance forming the matrix, and the three-dimensional mesh is present in the thermistor material. A thermistor material characterized by being dispersed in a discontinuous shape. 11. A matrix made of a substance having an insulating property, and a matrix having a three-dimensional network continuously dispersed therein, which has a different coefficient of thermal expansion from the matrix and when internal stress is generated by thermal expansion. A third phase composed of a substance that alleviates this, and discontinuously dispersed in the third phase,
A thermistor material comprising a dispersant comprising a substance having a different coefficient of thermal expansion from the matrix, wherein the dispersant comprises a semiconductor substance or a substance having electrical conductivity, and was discontinuously dispersed in the third phase. A thermistor material, characterized in that the dispersion material is dispersed in the thermistor material in a three-dimensional network discontinuously to form a network-shaped electrical path structure. 12. A third phase consisting of a matrix made of a substance having an insulating property and a substance having a three-dimensional mesh-like continuous dispersion in the matrix and having a coefficient of thermal expansion different from that of the matrix and a small elastic modulus. And a dispersant that is discontinuously dispersed in the third phase and that is made of a substance having a coefficient of thermal expansion different from that of the matrix, wherein the dispersant has a semiconductor substance or electrical conductivity. Consisting of a substance, the third phase has a coefficient of thermal expansion closer to the coefficient of thermal expansion of the matrix than the coefficient of thermal expansion of the dispersant, the dispersant dispersed discontinuously in the third phase. , A thermistor material, wherein the thermistor material has a three-dimensional network discontinuously dispersed to form a network-shaped electric path structure. 13. A matrix comprising an insulative substance and a first reinforcing layer having an insulative property comprising the same or similar substance as the matrix, which is continuously dispersed in a three-dimensional network in the matrix. A thermistor material comprising three phases, and a dispersant which is discontinuously dispersed in the reinforcing layer and is made of a semiconductor material having a different coefficient of thermal expansion from the matrix or a material having conductivity, wherein the dispersant is A thermistor material, wherein the thermistor material is three-dimensionally meshed and discontinuously dispersed, and the dispersion material forms a network-like electric path structure in the thermistor material. 14. A matrix raw material powder made of an insulating material, and a semiconductor material having a coefficient of thermal expansion different from that of the matrix raw material powder or a conductive material, and having a size of 1/2 or less of the matrix raw material powder. Raw material powder preparation step of mixing the dispersant raw material powder of 1., a shaping step of shaping the raw material powder into a predetermined shape to obtain a shaped body, and a matrix made of a substance having an insulating property by heating the shaped body. And a composite material forming step of forming a composite material comprising a matrix and a dispersion material made of a substance having a different coefficient of thermal expansion dispersed discontinuously in the matrix in a three-dimensional mesh shape. Manufacturing method of the thermistor material. 15. The method for producing a thermistor material according to claim 14, wherein in the raw material powder adjusting step, a dispersion material having a coefficient of thermal expansion different from that of the matrix is formed on the surface of the granulated powder having a predetermined shape as the main material of the matrix. A method for producing a thermistor material, characterized in that a raw material powder is prepared so as to be continuously present. 16. The surface of a matrix raw material powder made of a material having an insulating property is formed on a surface of a semiconductor material having a coefficient of thermal expansion different from that of the matrix raw material powder or a material having an electrical conductivity and having a size of 1/2 of the matrix raw material powder. Of the following dispersant raw material powder, and a dispersant having a coefficient of thermal expansion closer to that of the matrix raw material powder than the coefficient of thermal expansion of the dispersant raw material powder and formed by the dispersant raw material powder during temperature measurement It is made of a material that relaxes the internal stress caused by the difference in thermal expansion, and its size is 1 / of the matrix raw material powder.
A raw material powder preparation step of mixing two or less third phase raw material substances by sprinkling, a molding step of shaping the raw material powder into a predetermined shape to obtain a molded body, and heating the molded body to obtain an insulating property. From a matrix composed of a substance having a material having a coefficient of thermal expansion different from that of the matrix and having a coefficient of thermal expansion different from that of the matrix and relaxing the internal stress caused by the difference in thermal expansion. And a composite material forming step of forming a composite material composed of a third phase and a dispersant dispersed discontinuously in the third phase and made of a substance having a different coefficient of thermal expansion from the matrix. A method for manufacturing a characteristic thermistor material. 17. The surface of a matrix raw material powder made of an insulating material is provided on the surface thereof with a semiconductor material having a coefficient of thermal expansion different from that of the matrix raw material powder or a material having electrical conductivity and having a size of 1/2 of the matrix raw material powder. The following dispersant raw material powder is mixed with the third raw material powder that is the same as or similar to the matrix raw material powder and has a size equal to or less than 1/2 of the matrix raw material powder in a sprinkling manner. Raw material powder preparation step, molding step of shaping the raw material powder into a predetermined shape to obtain a molded body, heating the molded body to form a matrix made of an insulating material, and a three-dimensional mesh in the matrix. Phase continuously dispersed in the form of a matrix, which is composed of the same or similar substance as the matrix, as an insulating reinforcing phase, and a third phase And a composite material forming step of forming a composite material continuously dispersed and comprising a dispersion material made of a semiconductor material having a different coefficient of thermal expansion or a material having electrical conductivity, and a composite material forming step. Production method.