JPS6059187B2 - Thermistor composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel thermistor composition that is stable and has a low specific resistance.

A thermistor material whose resistance value has a negative slope with respect to temperature is a composite oxide made by mixing two or more types of oxides such as Mn, Co, Ni, Cu, Fe, Al, Si, etc. and heat-treated at 900 to 1300°C. something is well known.

Among these, the composite oxide containing Cu has a specific resistance of 100Ω.
Some are as small as 1 a or less, and are used as low-resistance thermistor materials. However, a thermistor element made of a material containing Cu has a resistance value that changes over time by +10
% or more and lacks stability, so it cannot be used as a highly accurate temperature detection or temperature compensation element. Therefore, a thermistor material with low specific resistance and excellent stability is required. An object of the present invention is to provide a thermistor material with low resistance and particularly excellent stability.

The present invention provides (a) a mixture of oxides of Mn, Co, and Re, or (b) an oxide of Mn, Co, and Re with additional Fe and N.
A composite oxide obtained by pulverizing and firing a mixture of any one of the oxides of i is characterized in that up to 52% of the total amount of metal components in the composite oxide are Re atoms.

Here, the reason why the Re content is set to 52% atoms is that if the material composition exceeds this value, the temperature change in resistance value, that is, the thermistor constant becomes small, and the material does not exhibit the characteristics as a thermistor. Note that a composition that does not contain Re is a conventional thermistor material. The present invention will be explained below with reference to Examples.

Example 1 Using MnO2, COO, and ReO2 as starting material powders, Table 1
Weigh out 50 dah so that the composition shown is as follows.

These powders are crushed and mixed for 4 hours using an agate mortar. Put this mixed powder into an alumina crucible.90
Heat treatment is performed at 0°C for 2 hours. Next, crush the 30 in an agate mortar for 4 hours and pressurize it to ()n/c71f to create a 12φ x 3" pellet. Heat treat this pellet at 1250°C for 2 hours to make a ceramic. Conductive paint was applied to both sides of this ceramic to form electrodes, and the thermistor characteristics and its stability were investigated.Stability was evaluated by the change in resistance value at 150°C and 200011 Terama.Table 1 Sample No. 1 in Table 1 is a well-known thermistor material and is listed as a reference.The thermistor compositions No. 2 to 14 in Table 1 containing up to 52% Re by atoms are all shown in Table 1. The specific resistance was lower than that of NO.1, and the stability was also good.

In addition, the thermistor constant decreases with the amount of Re,
No. As shown in 15, a material containing 54% atoms of Re has a value smaller than 500K and is less useful as a thermistor. Example 2 Using Mr1304, C0304, Ni0, and Re02 as starting materials, a ceramic having the composition shown in Table 2 was prepared in the same manner as in Example 1, and its thermistor characteristics and stability were investigated.

However, sample No. in Table 2. 1 is a conventionally well-known thermistor material and is listed as a reference.

No. in Table 2. Those containing up to 52% Re of atoms from 2 to 15 are NO. It has a low resistivity compared to l,
Stability is also good. No. A material containing M% atoms of Re of 16 has a thermistor constant smaller than 500K and is less useful as a thermistor. Example 3 Using Mr02, C00, Fe203, and Re02 as starting materials, ceramics having the composition shown in Table 3 were prepared in the same manner as in Example 1, and their thermistor characteristics and stability were investigated.

However, sample No. in Table 3. 1 is a conventionally well-known thermistor material and is listed as a reference.

No. of Table 3. Those containing up to 52% Re atoms of 2 to 13 are P&). It has a lower resistivity and better stability than one that does not contain Re of 1. No. A thermistor constant of a material containing M% of Re atoms of l4 is smaller than 500K, and is less useful as a thermistor. As mentioned above, since Re atoms account for up to 52% of the total amount of metal components in the composite oxide, it is possible to create a low-resistance and stable thermistor material. We were able to provide the device.

Claims (1)

[Claims] 1 (a) A mixture of oxides of Mn, Co, and Re, or (b) a mixture of oxides of Mn, Co, and Re with either one of oxides of Fe or Ni is crushed and fired. In a composite oxide, the amount of metal components in the composite oxide is 5
A thermistor composition characterized in that up to 2% atoms are Re.