JPS6027653A - Ceramic resistor material - 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 Application of the Invention] The present invention relates to a 3iC-AtN ceramic resistance material.

[Background of the invention]

Lamic materials represented by S iC+ 5jsN4s A, tz03, etc. have a high heat resistance and are also excellent in mechanical strength and acid resistance, so their application as high-temperature structural materials is being considered.

On the other hand, some efforts have been made to utilize the above-mentioned materials as electrical component materials, including insulating substrates and various heaters.

Some products such as fuel igniters, glow plugs, noise radio wave prevention resistors, etc. have been put into practical use. When used in SiC, Si3N4-based sacrificial heaters or resistors, the materials in the high resistance or insulation resistance range must be reduced to a practical resistivity of 1 to 104Ω by some means. There is a need to. Recently, various methods of reducing the resistivity of these materials have been studied.For example, SIC and Si3N4
It has been revealed that a resistivity of 1 to 102 Ω- can be obtained by a mixed sintered body of .

[Purpose of the invention]

) The present invention was obtained as a result of investigating the influence of dopants on SiC for many materials, and it is a novel ceramic resistor having a resistivity of 1 to 104 Ω at room temperature by combining materials different from the above-mentioned known examples. The purpose of the drink is to provide ingredients.

[Summary of the invention]

In other words, the feature of the present invention is that a SiC powder body consisting of two components, SiC and AtN, and a 40- to 0-piece SiC powder body are sintered at a temperature of 1700711' or higher in a non-oxidizing atmosphere.

Sic here! : The mixing amount of A and zN was limited because
When ktN is less than 10%, the variation in resistivity is large and reproducibility is poor, and when ktN is more than 60% by weight, the resistivity of the sintered body rapidly increases to more than 104Ω, which limits its practical use as a resistive material. This occurs because it becomes an insulator. In addition, the sintering conditions were limited to sic and ht in an oxidizing atmosphere.
N oxidizes and does not become densified, and the resistivity of the sintered body is 10.
This is because if the sintering temperature is 1800C or less, the relative density is 90% or less, resulting in poor compactness and insufficient mechanical strength.

[Embodiments of the invention]

The present invention will be explained in detail with reference to specific examples.

(Example 1) Green SiC powder with an average particle size of 2 μm was added with an average particle size of 0.5 μm.
m of ALN powders were mixed at different mixing ratios. Then,
The mixed powder f: After preforming at a pressure of 1000 Kq/ca, the molded body was put into a graphite die and 3X 10” Tor
Hot press sintered under pressure of r.

The sintering conditions were a pressure of 300 Kg/crA and a temperature of 195 (
ICs time is 1 h. Table 1 shows the relative density and electrical resistivity of the obtained sintered bodies.

, Table 1 As is clear from the results in Table 1, the sintered body of the composition containing 4° to 90% by weight of 5tc and 10 to 60% by weight of AtN is densely sintered to a relative density of 95% or more, and at room temperature. It can be seen that it has a resistivity of 1 to 104 Ωα. Si
It is not clear why the resistivity is drastically reduced when the insulating roux is added to C, especially when the amount of A,/, and N is around 10% by weight, but when sintered under reduced pressure at 17,000 or more, A
It is believed that a part of 4N thermally decomposes to generate At and N2, which act as dopants for SiC and effectively reduce the resistivity.

(Example 2) Using the same SiC and AAN powder as in Example 1, 5t
After preparing a composition of 50% c and 50% by weight AtN and preforming it at a pressure of 1000 Kg/crA,
Hot press sintering was performed in At gas of IKf/cr4.

The sintering conditions were a pressure of 300 Kf/J, a temperature of 1950 Cs, and a time of 1 h. This sintered body has a relative density of 9% and a resistivity of 2%.
A ceramic resistance material having properties such as a bending strength of 43 Kq/- and a dense and high mechanical strength was obtained. This sintered body was heat-treated in the atmosphere at 1100 tons for 100 hours continuously. The oxidation amount increase is about 34/ff
It is made of a material that has a small amount of 1 liter and has excellent oxidation resistance.

(Example 3) Using the same raw material powder as in Example 1, 5tc50% by weight, A
A composition containing 50% by weight of tN was prepared, and after the entire composition was powder compacted, it was hot press sintered in a vacuum. Sintering conditions were: pressure 300Kf/d, temperature 1700-2000C, time 1h.
It is. Table 2 shows the relative density, resistivity and bending strength of the sintered bodies obtained.

From the results in Table 2, it is clear that when the sintering temperature is below 1800 t:', the relative density is below 90%, resulting in poor compactness, and the bending strength is also low, making it impractical. When it reaches 2050t:', there is a slight overburning, and the density and strength are slightly reduced. Such a decrease in properties due to sintering temperature was also observed at other composition ratios. Therefore, the sintering temperature is 1 sooc or more, preferably 1 sooc
800-2000C is suitable.

〔Effect of the invention〕

Claims (1)

[Claims] 1. It is made of a mixed sintered body of silicon carbide and aluminum nitride. 9. It has a density of 90% or more of the theoretical density and 1 to 1 at the layer temperature.
A ceramic resistive material having a resistivity of 0.04Ω or less.