JPS63136502A - Thermistor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] ■ Background of the invention Technical field The present invention relates to a thermistor element for high temperatures.

Prior art and its problems A thermistor is a temperature sensor that utilizes the temperature dependence of the electrical resistance of a temperature-sensitive resistor, and is widely used for temperature measurement, temperature control, etc. Particularly for high temperature applications, examples include automobile exhaust gas temperature detection sensors and electric furnace thermometers 7! jl
Used in l sensors, etc.

The structure of the thermistor element is, for example, disclosed in Japanese Patent Application Laid-Open No. 60-3710.
As described in No. 1, conventionally, electrode parts are buried in sintered ceramic, which is a temperature-sensitive material, so there are many cases where the buried electrode parts are damaged and the platinum electrodes used for the electrodes are damaged. It has disadvantages such as being expensive.

In order to deal with these shortcomings, the
No. 01 states, ``A columnar insulator, a protective film insulator surrounding the columnar insulator, at least one pair of conductors formed between both insulators, and an electrode provided on the conductor to communicate with the outside. A thermistor element is disclosed that is an "integrated structure having a temperature-sensitive material placed to short-circuit the conductors."

However, in this proposal, when connecting an insulator and a conductor, the conductor is applied to a raw sheet of the insulator, rolled up and fired, or the conductor is printed on a column-shaped insulator. A conductor is formed on a fired or sintered insulator by vapor deposition, sputtering, or the like. Then, a temperature-sensitive material is welded or thermally sprayed to the thus integrated insulator and conductor to integrate them.

That is, the conductor and temperature-sensitive material are supported on an insulator, and the mechanical strength of the element is determined by the insulator, so the element must be large in order to obtain sufficient mechanical strength. ' Also, it is not perfect in preventing peeling between conductors, insulating materials, and temperature-sensitive materials during high-temperature use. For this reason, the protective film must be made thicker.

Furthermore, since a separate electrode is formed at the rear end of the conductor, T
The stability of these electrical connections is also not sufficient.

Furthermore, in JP-A No. 60-49607, a polycrystalline sintered body as a thermistor material and a quadriconductive ceramic as a pair of conductors are integrated by hot-press sintering the respective raw materials. What has been transformed is disclosed.

By the way, a temperature sensing element for high temperature use must be long to some extent in order to protect the lead connection portion.

However, in order to configure this, a long conductive material is placed at the rear end of the thermistor material and then sintered and integrated.
To form a pair of conductors, the conductors must be cut out to the thermistor chip.

Therefore, the manufacturing process becomes complicated, and the detection accuracy is also affected by the grinding accuracy. Furthermore, in order to increase the adhesive strength between the conductor and the thermistor chip, the width of the columnar body must be increased, resulting in an increase in the size of the device. Or the mechanical strength is not sufficient.

■ Purpose of the Invention The purpose of the present invention is to integrate electrical connections between the thermistor material, electrodes, and lead wires, to be small in size, to have sufficient stability and reliability when used at high temperatures, and to be mechanically It is an object of the present invention to provide a thermistor element which has high strength and can be formed into a thin film when forming a protective film.

■Disclosure of invention Such objects are achieved by the invention described below.

That is, the first aspect of the present invention is a thermistor element that integrally includes a pair of conductor, an insulator, and a thermistor chip, in which the pair of conductor materials are arranged on both sides of the insulator material, and This thermistor element is characterized in that a thermistor material is arranged at the tip of an insulating material so as to be in contact with both conductive materials, and the stiffness is integrated by heating with a presser.

Further, a second invention is a thermistor element that integrally includes a pair of conductor, an insulator, and a thermistor chip, in which the pair of conductor materials are arranged on both sides of the insulator material, and the insulator material A thermistor element is placed at the tip of the conductor so that it is in contact with both conductor materials, and these are integrated by heating with a presser, and a protective film is placed on the rear ends of the conductor and insulator. This is a thermistor element characterized by the following.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The thermistor element of the present invention is one in which a pair of conductor, an insulator, and a thermistor chip are integrally formed, and a pair of conductor materials are arranged on both sides of an insulator material, and A thermistor material is placed at the tip of both 41' so as to be in contact with the body material, and this is heated by a presser and integrated.

FIG. 1 is a sectional view showing one embodiment of the thermistor element of the present invention.

As shown in FIG. 1, the thermistor element 1 of the present invention usually has a prismatic external shape. Preferably, the thermistor chip 11 is provided at the tip of the insulator 13, and a pair of conductors 12 are arranged so as to cover both sides of the thermistor chip 11 and the insulator 13.

In the present invention, the thermistor element is not limited to such a structure, but may include a pair of conductors 12 disposed on both sides of an insulator 13, and further in contact with the pair of conductors 12 at the tip of the insulator 13. Any type of integrated structure including the thermistor chip 11 may be used.

In this case, the conductor 12.12 and the insulator 13 may be connected to the rear end of the thermistor chip 11.

However, in this case, in order to obtain sufficient mechanical strength,
Since the thermistor chip 11 and the element become larger, the conductors 12 and 12 are connected to the thermistor chip 11 as shown in the figure.
It is preferable to reach the tip of the side surface.

If the conductor 12.12 is brought into contact with a portion of the side surface and rear end surface of the thermistor chip 11 as shown in the figure, the mechanical strength and stability of the electrical connection will be improved, and the device can be made smaller. .

In the present invention, the value obtained by dividing the J7 of the conductor by the thickness of the insulator is 0.1 to 10, preferably 0.4 to 10.
It is better to set it to 1.

If this value is less than 0.1, the device becomes large, and if it exceeds 10, the insulation between the pair of conductors becomes poor.

The size of the thermistor element of the present invention is usually 30 to 8
0[nIl+, width 0.45-0.75n++n, thickness 0
．． 24 to 10.5 mm, and the size of the thermistor chip is 0.45 to 0.75 mm in length and 0.45 to 0.0 mm in width.
．． 75 [0111, the thickness is 0.2 to 0.5 mm, and the thickness of the insulator is preferably 0.2 to 0.5 n+m.

The insulator material used in the present invention may be any material that has a higher resistance than the thermistor material, and is about 102 to 1010 times higher than the resistance value of the thermistor material, preferably 10
It only needs to be about 8 to 1010 times higher, and the 11 body is A12o3. MgO1S i3~4, A, eN, B
Examples include N.

In addition, as a thermistor material, specifically 5iC-8
4C-BN system, Ax2o3-(T i C, Cr3 C
2. TiN) system, BN-(TiN, NbN) system,
N + OM n 20 ]-Al2O2, %, Mg0
-(TaC, TiC) system, etc. are mentioned.

These materials have different resistance specifications depending on their use, but
For example, the resistance value at 100°C is from several ohms to several hundred ohms, and it is possible to obtain the desired specification value by changing the composition ratio of the material, the shape of the chip, etc. can.

As the conductor material, W, MOlMo-Mn system, Fe-
Metal materials such as Ni-Co series and Ti series, 5iC-TiC series, 5iC-CrB2 series, ZrN series, T i C-T i
Examples include conductive inorganic materials such as N-based materials, MoSi2, and LaCrO3.

The thermistor element of the present invention is obtained by heating under pressure F as described above.

For example, first, sheets of thermistor material, insulator material, and conductor material are each made into predetermined sizes, and as shown in FIG. 2a, the thermistor material 2 is
An insulating material 22 is arranged in contact with both sides of the 11th surface, and a conductive material 23 is stacked in contact with the 11th surface and the lower surface, respectively, and these are heated under pressure, and then the desired size is obtained as shown in FIG. 2b. Examples include a method of cutting into pieces.

In the illustrated example, the thickness of the thermistor material and the insulator material are the same, but the shape of the sheet-like material to be prepared may be determined as appropriate in accordance with the shape of the desired thermistor element.

According to such a method, it is possible to simultaneously create about 50 to several thousand thermistor elements.

Specifically, the pressure heating may be performed by a hot press (HP) method or a hot isostatic pressure (HIP) method.

In the HP method, under an oxygen atmosphere such as the atmosphere, or in a vacuum,
Under an inert atmosphere such as Ar or N2, 50 to 300 g
/cd at a temperature of 300-2200°C, 0.2
Heat for about 2 hours.

The reason for such conditions is that if the weight is less than 50 kg/c, the bonding will be insufficient, and if it exceeds 300 kg/c, the press die used will be severely worn out, making it difficult to select the material, and productivity will deteriorate. This is because if the temperature is less than 300°C, the bonding will be insufficient, and if the temperature exceeds 2200°C, variations in properties (resistance value, etc.) depending on the composition of the thermistor material etc. will increase rapidly.

In addition, in the HIP method, 50~
Under pressure of 1500g/crrf, 300-2200
Heat at a temperature of 0.2-2 hours.

These conditions are used because if the weight is less than 50 kg/c, the bonding will be insufficient, and if it exceeds 1,500 kg/c, it will be difficult to control the mutual diffusion between the materials, resulting in poor workability. If the temperature is less than 300° C., the bonding will be insufficient, and if the temperature exceeds 2200° C., the variation in properties (resistance value, etc.) depending on the composition of the thermistor material etc. will increase rapidly.

In such a case, each material used may be a sheet of raw material that becomes each component upon heating.

However, when using raw materials, I (P or HIP)
During this process, changes in size or shape may occur, so it is preferable that each material be sintered or calcined in advance. In this case, the sintering temperature may be set to a suitable temperature for each material.

In the present invention, the thermistor material and the pair of conductor materials are firmly bonded by mutual diffusion by heating under pressure in one axis direction (HP method) or three axis directions (HIP method). I can do it.

It is preferable that such a diffusion or reaction layer has a thickness of about several to several tens of centimeters.

For such bonding, it is necessary that the thermal expansion coefficients of the thermistor material and the conductor material are similar to each other, and by controlling the pressure, heating, atmosphere, etc. as described in 1. This aims at mutual diffusion of the material and the conductor material.

For this reason, the following combinations of the thermistor material and conductor material can be cited.

Thermistor material Conductor material l) Coefficient of thermal expansion: (30-55) x 10-7/
”C3iC-84C-BN series 5iC-Tie series 5
iC-Cr mouth. System 'i, Mo, Fe-N1-(:o system ■C2) Coefficient of thermal expansion: (55-75) X 10-? /”
CA fl 203- (TiC1 Cr3C2, TiN) ZrN, f-BN-
(TiN, NbN); feTie-TiN system 3
) Thermal expansion coefficient: '75 x 10-7/''C or more Ni0
-Mn20. - Al1203 system Fe-Ti-Cr system JO- (TaC, TiC) system Fe-Ni-Cr
In the present invention, it is preferable to form a protective film 14 on the thermistor element l as shown in FIG. In this case, it is preferable to form a thin film such as a sol-gel coat as a protective film.

Specifically, a metal alkoxide (silicon alkoxide, aluminum alkoxide, zirconium alkoxide, etc.) and a solvent (isopropyl alcohol, etc.) are added in a molar ratio of 1:5, and a stabilizer is added as necessary to the grains. A solution was prepared, and a thermistor element with the external electrode part (a part of the conductor opposite to the thermistor) masked was dipped in this solution, and the relative humidity was 60% at room temperature.
It is formed by drying under the following conditions and then firing. Firing may be performed at about 500° C. for about 10 minutes at normal pressure.

Further, control of n=t may be performed by increasing the number of dipping and baking operations.

By forming a thin film in this manner, a thermistor element with excellent heat resistance can be obtained.

In addition, various types of protective films can be formed.

Note that it is sufficient that the area where the protective film is not formed is about 3 to 10 mm.

Further, in order to fix the lead wire, brazing or the like may be performed in the area where the above-mentioned protective film is not formed.

v== Specific Effects of the Invention According to the present invention, a pair of conductor, an insulator, and a thermistor chip are integrally provided, and a pair of conductor materials are arranged on both sides of the insulator material, Furthermore, the thermistor material is placed at the tip of the insulator material so that it is in contact with both conductor materials, and this is heated under pressure to integrate the thermistor material, making it possible to integrate the electrical connections between the thermistor material, electrode, and lead wire. Therefore, it is possible to obtain a thermistor element which is small in size, has sufficient stability and reliability when used at high temperatures, and has high mechanical strength. Further, when forming the protective film, it is possible to make the film thinner. Furthermore, there will be 8 spins produced.

(2) Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in more detail.

An Al2O2-TiCl co-sintered body (
4165mm, length 1.6mm, thickness 0.5mm), T i C-T i N composite sintered body (width 65mm, length 130+n+n, thickness 0.3mm) as the conductor material and Al1203 as the insulator material. (width 65mm, length 6
4.2 mm and 0.5 mm thick), and as shown in FIG. 2a, they were stacked and heated under pressure using a hot press method to bond them.

In this case, heating was performed at a temperature of 1300°C in an Ar atmosphere for 1
This was carried out for 30 minutes under a pressure of 50 g/l.

The composite sintered body created in this way ([l+65mm
, length 130 mm, thickness 1.1 mm) was taken out from the mold and returned to room temperature. After that, the upper and lower surfaces are processed by lapping for about 20 minutes, and the thermistor element (rllo, 75 mm, length 65IIl111, thickness 1.1mm; thermistor chip part The size of 0.7
5xO675X0.5+nm) Conductor isometry 0.3m
m). 100% from one composite sintered body
Thermistor elements were obtained.

The thermistor element A is the one after the aging treatment.

After measuring the resistance of this thermistor element A at 40° C., an AJ2203 film was formed by the sol-gel method as follows.

A solution was prepared by adding 5 moles of isopropyl alcohol to 1 mole of aluminum isopropoxide, and further adding a stabilizer.

Thermistor element A, whose external electrode portion (a portion having a length of 5 ram from the end in the direction opposite to the thermistor chip portion) was masked by taping, was dipped in this solution and air-dried at room temperature and relative humidity of 40%. this thing 5
Baked under normal pressure at 00°C for 10 minutes to achieve AM20. A film was formed.

This combined operation of dipping and baking was repeated 2 to 3 times to form an AIL 20° film with a thickness of 1 to 3 layers.

This is called thermistor element B.

In the thermistor element A, the thermistor material is
i C-B 4 C-B N @Changed the composite sintered body, changed the conductor material to 5iC-Tic composite sintered body, further changed the insulator material to BH, and heated to 150g/c, 1900℃,
Thermistor element C was subjected to HP treatment in Ar for 30 minutes.
I got it.

Sample B was prepared using aluminum isopropoxide and isopropyl alcohol for this thermistor element C.
In the same manner as above, an A2□03 barrier film was formed to obtain a thermistor element.

When we investigated the change in resistance of these thermistor elements A, B, C, and D after 3000 hours of high-temperature storage, we found that at 300°C, the change in resistance was less than 0.5%F, and at 500°C, it was 1%.
Good results were obtained with only the following changes observed.

In addition, when storing at 500℃, the same conditions as when mounting were used.
When the 30 mm tip was inserted into a thermostat at 500°C,
The temperature of the brazed lead wire portion at the rear end was approximately 200°C.

From the above, the effects of the present invention are clear.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the thermistor element of the present invention. FIGS. 2a and 2b are perspective views for explaining the steps in manufacturing the thermistor element of the present invention. Explanation of symbols 1...Thermistor element, 11...Thermistor chip, 12-...Conductor, 13
...Insulator, 14...Protective film 21-...
・Thermistor material, 22... Insulator material, 23-
・・Conductor material FIG, 1 FIG, 2a FIG, 2b Day Yo; Yo

Claims (5)

[Claims] (1) A thermistor element that integrally includes a pair of conductor, an insulator, and a thermistor chip, in which the pair of conductor materials are arranged on both sides of the insulator material, and the two conductor materials are disposed on both sides of the insulator material. Place the thermistor material in contact with the conductor material,
A thermistor element characterized by being integrated by pressurizing and heating the thermistor element. (2) The thermistor element according to claim 1, wherein the insulator material, the conductor material, and the thermistor material are sintered or calcined in advance. (3) The thermistor element according to claim 1 or 2, which has a thermistor chip at the tip of the insulator, and a pair of conductors covering both sides of the thermistor chip and the insulator. (4) The value obtained by dividing the thickness of the conductor by the thickness of the insulator is 0.1
~10 The thermistor element according to any one of claims 1 to 3. (5) A thermistor element that integrally includes a pair of conductor, an insulator, and a thermistor chip, in which the pair of conductor materials are arranged on both sides of the insulator material, and the two conductor materials are disposed on both sides of the insulator material. Place the thermistor material in contact with the conductor material,
This is integrated by heating under pressure.
A thermistor element characterized in that a protective film is provided on the rear ends of the conductor and the insulator.