JPS62263606A - Manufacture of oxide semiconductor porcelain for thermistor - 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 Field of Industrial Application The present invention relates to a method for producing oxide semiconductor ceramics for thermistors that require high reliability and are used in combustion control circuits, etc. in the temperature range of 150 to 6Q°C. It is related to.

Conventional technology Conventionally, semiconductor materials for general-purpose thermistors were mainly made of Mn.
-1o-Ni -Cu is an oxide material that is a combination of two to four components, and is mainly used as a disk-shaped thermistor, and the operating temperature range is limited to 150°C or less. It is something. Further, even if the glass-filled type or glass-coated type is used, the operating temperature range is at most 300°C.

On the other hand, stabilized zirconia (ZrOz-Y20s+Zr0
2-CaO), My-Human 1-Cr-Fa oxide spinel systems, etc. have been developed and are used in automotive sensors.

Problems to be Solved by the Invention In such a conventional configuration, semiconductor materials for general-purpose thermistors have a large resistance value fluctuation when used at high temperatures.
It could not be used at high temperatures exceeding 0°C. Also, in order to obtain a high temperature thermistor,
The firing temperature was as high as 1,600°C or higher, and could not be fired using a normal electric furnace (maximum of 1,600°C). Moreover, the resistance value of sintered bodies of these oxides changes significantly over time, and even those that are extremely stable have a resistance value of 10%.
% (after 1000 hours), and there was a problem with stability over time.

The present invention solves these problems, and
The present invention provides a method for obtaining an oxide semiconductor ceramic for a thermistor that exhibits an appropriate resistance value even at 500° C. and can be stably used.

Means for Solving the Problem In order to solve this problem, the present invention has been proposed by the present inventor as a result of various studies (Japanese Patent Application No. 59-2367).
No. 16), the metal elements include Mn 60.0 to 98.5 atomic % and NiQ 1 to 5.0 atomic %.

It has a composition containing a total of 100 atoms of cro, s ~ 5.0 at%, Yo, 2 to 5.0 atoms, and Zr 0.05 to 28.0 atoms, and 350 to 166
After sintering at a temperature of 0℃, the temperature above is also 100~30℃.
It is resintered at a temperature as low as 0° C. and under pressure. Similarly, Mn60. O~98.6 atomic%,
N1c), 1-es, o atom%, Oro, 3-5.
0 atom %, Y0.2-5.0 atom H and Zr□, 06
It has a composition containing 5 types of ~28.0 atomic atoms for a total of 100 atomic percent, and 2.0 atomic percent (excluding ○ atoms) of Si based on the main component, and 135Q ~155
After sintering at a temperature of 0℃, the temperature is 100~30% higher than the above temperature.
The present invention provides a method for manufacturing oxide semiconductor porcelain for a thermistor, which is characterized by resintering at a temperature as low as about 0° C. and under pressure.

Effect: This structure makes the ceramic more dense and reduces the rate of change in resistance over time during high temperature use as a thermistor.

Example Examples of the present invention will be described below.

Commercially available raw materials MnCO3, Nip, Cr2O5 and Y2
ZrO2 containing O3 is blended to have a composition of each metal atom as shown in the table below. This is mixed in a ball mill, dried, and calcined in air at 1000"C for 2 hours. This is ground again in a ball mill, and the resulting slurry is dried. Polyvinyl alcohol is added as a binder to this and mixed. Take the amount 3 OramφX
Form into a block of 15a+φ. Then, this molded body is fired in air at iso°C for 2 hours. The apparent porosity of the sintered body thus obtained is 3% or less. Furthermore, this sintered body was processed using a hot isostatic pressing apparatus.

Under pressure of 1 o○○ using inert gas,
It was resintered at 1300°C for 1 hour. Further, heat treatment was performed in air as necessary. The block obtained in this way is sliced into wafers with a thickness of 200 μm, platinum electrodes are provided on both sides of the wafer, and chips of the desired size are processed. This is sealed and sealed in a glass tube using the slug lead as a terminal. A glass-encapsulated thermistor was obtained.

The rate of change in resistance value of this thermistor over time at 500'C for 1600 hours is also shown in the table below.

(Hereinafter, blank space) As can be seen from the table above, the embodiments of the present invention are as follows:
In both cases, the rate of change in resistance value over time is 0.6 to 3.0 inches smaller than in the case where the resintering treatment under pressure and high temperature is not performed, and the effect is recognized. Furthermore, the ceramic itself was extremely dense and homogeneous with almost no pores. Furthermore, the reason why the composition range is limited here is that the resistance value as a senna is in the range of 100Ω to 500Ω in the temperature range of 300 to 600′C.

The figure shows the change over time in the resistance value of the thermistor using the material shown in sample plate 3 at so o'c.

In the figure, the solid line shows the change according to this embodiment, and the broken line shows the change according to the conventional example without hot isostatic pressing. As is clear from the figure, the thermistor magnet according to the present invention is very stable.

Effects of the Invention As described above, according to the present invention, by re-sintering the sintered body of the oxide semiconductor for thermistor under pressure and high temperature, it becomes more dense and homogeneous than conventional products. It is considered to be most suitable for temperature sensors that require high reliability over a long period of time at temperatures up to 500"C.In particular, for thermistors that are manufactured by processing blocks into chip shapes, chip-shaped Since the coefficient of variation of the resistance value of the element is small and it is excellent in mass production, it can be fully expected to be applied to high value-added products.

[Brief explanation of drawings]

The section is a diagram showing the resistance value aging rate characteristics at 600° C. of glass-encapsulated thermistors using oxide semiconductor ceramics for thermistors according to the present invention and the conventional method. Name of agent: Patent attorney Toshio Nakao and 1 other person C%
ノ (hr) - Masaki

Claims (2)

[Claims] (1) As metal elements, manganese 60.0-98.5 atomic%, nickel 0.1-5.0 atomic%, chromium 0.3-98.5 atomic%
6.0 at%, yttrium 0.2 to 5.0 at%, and zirconium 0.05 to 28.0 at%, with a total of 100 at%, and 1350 to 15
After sintering at a temperature of 50℃, the temperature is 100~3 higher than the above temperature.
A method for producing oxide semiconductor porcelain for a thermistor, which involves resintering at a temperature as low as 00°C and under pressure. (2) Metal elements: manganese 60.0-98.5 at%, nickel 0.1-5.0 at%, chromium 0.3-5
．． 0 atom%, yttrium 0.2 to 5.0 atom%, and zirconium 0.05 to 28.0 atom%, a total of 1
After sintering at a temperature of 1350 to 1550°C, 100% higher than the above temperature
A method for manufacturing oxide semiconductor porcelain for a thermistor, which involves resintering at a temperature as low as ~300°C and under pressure.