JPS6022482B2 - Manufacturing method of oxide semiconductor for thermistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a thermistor with a negative temperature coefficient of resistance characterized by easily doping copper into manganese nickel spinel containing chromium as a solid solution and providing a thermistor with a wide range of properties. The present invention relates to a method of manufacturing an oxide semiconductor for a thermistor.

Conventionally, the manufacturing method for commercially available general-purpose thermistors with a negative temperature coefficient of resistance is similar to the manufacturing process of other ceramics, in which oxides with the desired composition are blended, and this is mixed, mixed, mixed, wet-pulverized, granulated, etc. It is common to go through a process of molding and firing.

In addition, the oxide composition for thermistors, which consists of three components of manganese oxide, nickel oxide, and oxidized steel, is already widely known [Hitachi, Ltd. Central Research Laboratory 20th Anniversary Collection, p.
30-46, 1960], and a four-component system in which chromium oxide was added thereto was proposed earlier by the present applicant.

The present invention is a method for manufacturing the above four-component thermistor of manganese, nickel, chromium, and copper, in which a chromium solid solution manganese nickel spinel element is impregnated with a copper-bolycarboxylic acid key salt solution, thereby doping copper with manganese. The present invention is characterized by obtaining a four-component thermistor of nickel, chromium, and copper.

The present invention will be explained below with reference to Examples.

Commercially available raw materials M core 03, Ni0 and Cr203 were used as Mh:
Ni:Cr=80:17.5:2.5 atomic% was mixed, mixed in a ball mill for 2 hours, dried, temporarily held at 800 qo, and further ground and dried in a ball mill. , a molded body is obtained through a granulation and molding process.

This molded body is fired at a low temperature of 800 to 100 mm to obtain a highly porous element. After impregnating this element with a copper-ethylenediaminetetraacetic acid solution (hereinafter abbreviated as EDTA),
After drying at 0°C, it was fired in air at 1200°C for 2 hours.
Here, the doped steel content can be changed by changing the concentration of the copper-EDTN solution and the immersion time. That is, the final composition ratio of 1 sand immersed using IM solution is Mn:Ni:Cu:Cr:79.6
:17.4:0.5:2.5 atomic%, 8M steel-EDT
The sand soaked product of 1 using solution A is Mm:Ni:C
u:Cr=78.2:17.1:2.3:2.4 atomic%
Met. In cases where the composition is determined at the time of compounding, as in the case of a dependent product, it is not functional to cover a diverse range of properties. In other words, it is limited to one property and one composition ratio. However, if the manufacturing method of the present invention is used to manufacture basic chromium solid solution manganese-nickel spinel, it is industrially effective in that it is possible to easily meet a wide range of device characteristics requirements. is big. In particular, manganese and nickel constitute spinel in all compositions and are stable, and by solid solution of chromium, high temperature load characteristics (DCIOV load, 150
It is also a great advantage that by doping with copper, it is possible to easily obtain the characteristics of a manganese-nickel-chromium-copper composition with a wide range of properties. Furthermore, the reason for limiting the thermistor composition in the scope of claims is due to the characteristic values of general-purpose thermistors that are already commercially available (specific resistance 100 skin to IMO skin, B constant in the range 100 pK to 60000 K). be.

Furthermore, the impregnation solution is limited to copper-polycarboxylic acid salt because the metal and polycarboxylic acid have a large cage-forming ability and easily cause a substitution reaction, and the solution pH is strongly acidic like inorganic salts. In addition, the organic acid does not dissolve the element and has high solubility in neutral conditions.
This is because it has the advantage of being decomposed as

- The present invention is configured as described above, and it is possible to easily provide a thermistor with a wide range of characteristics, and its industrial efficiency is great.

Claims (1)

[Claims] 1. In a sintered mixture of metal oxides, the metal elements are 94.6 to 30 at.% of manganese, 5 to 30 at.% of nickel, 0.1 to 15 at.% of copper, and 0.3 to 40 at.% of chromium. In order to obtain an oxide semiconductor for a thermistor containing a total of 100 atomic percent of seeds, the device is characterized by impregnating manganese, nickel, and chromium component-based elements in a copper-polycarboxylic acid solution, then drying and firing them to dope them with copper. A method for manufacturing an oxide semiconductor for a thermistor.