JPS5815081A - Low heat-expansion heating body composition - 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 The present invention relates to a low thermal expansion heating element composition that is resistant to rapid heating and cooling.

Conventionally, nichrome wire, tungsten wire, molybdenum wire,
Heaters such as 5iC- have been used as heat sources. However, the biggest drawback of these was that they could break due to rapid heating and cooling. 5iC-eucryptite-8i0
A low thermal expansion heating element made of a 2+ clay material or the like could not obtain low electrical resistance due to the nature of SiC. Not yet (T
iC, T iN, W.C.

ZrC, ZrN)-eucryptite-(Zn OH
S r O+ B a O+ S 102 t T 10
2 + A l 203 t L 120 + Na
20°F e2031c r 203, z r0
2) The low thermal expansion heating element made of the above had the disadvantage of poor moldability during manufacture.

To solve these problems, it is necessary to develop a heating element composition that has a smaller coefficient of thermal expansion than the material and has a lower electric resistance.

The present invention eliminates such conventional drawbacks and provides a new porcelain body composition that has all the necessary conditions as a heating element.

That is, the low thermal expansion heating element composition according to the present invention is TiC
, TiN, WC, ZrC, ZrN in a total of 38 to 80% by weight, eucryptite (Li20
・Al2O3・2S102) 1s~60% by weight
.

Consisting of a range of clayey substances of up to 5% by weight, with a total of 1
00% by weight.

The reaction between the carbide, nitride and eucryptite is mainly a reaction between the component and the L120 component, but the amount of reaction is small. In addition, carbide is produced by this reaction.

The reaction product exists between nitride and eucryptite,
It works to relieve strain due to the difference in thermal expansion coefficient between the two. Most of the crystal phases are carbides, nitrides, and eucryptite. Therefore, as shown in Table 1 below, the coexistence of carbides, nitrides, and eucryptite with different thermal expansion coefficients cancels out the thermal expansion effect.

Table 1 A heating element having a small coefficient of thermal expansion and low electrical resistance can be obtained by using a composition within the above range.

In addition, in the above composition, Tic, TiN, WC, and ZrC.

If the total amount of one or more ZrN is less than 38% by weight, the electrical resistance value will increase, and if it exceeds 80% by weight, the sinterability will decrease and the coefficient of thermal expansion will increase.

Furthermore, if eucryptite is less than 18% by weight, the thermal expansion coefficient increases, and if it exceeds 60% by weight, the electrical resistance value increases and the thermal expansion coefficient decreases. In addition, 5 clayey substances
When the weight percentage is exceeded, the coefficient of thermal expansion increases.

As described above, a heating element cannot be used under harsh conditions such as rapid heating and cooling, so the coefficient of thermal expansion is very high.

The relationship with heat resistance, electrical resistance, etc. is very important, and the composition within the scope of the present invention is provided as a material that satisfies these conditions.

Hereinafter, the present invention will be specifically explained with reference to Examples.

For the sample preparation process, industrial raw materials (purity of 98% or more) are used.
Tic, We, ZrC, ZrN, eucryptite, and a commercially available clay material were used, and wet mixing was performed using a urethane-lined pot to prevent contamination with impurities. Further, as a procedure for preparing a sample, raw materials were mixed to have the composition ratio shown in Table 2 below, and then molded using a wet extrusion molding machine. Firing was carried out in Ar gas at a temperature of 1300-1450°C, and the shape was 10φ x 200'mm. The obtained device exhibited various characteristics as shown in Table 3 below.

Margin below Table 3 Samples in Table 3, %10 to 14 are conventional examples, and in order, nichrome wire, tungsten laminated ceramic heater, SiC heater, 5iC-eucryptite heater, TiC, TiN, WC, ZrC, ZrN-eucryptite-ZnO, SrO, BaO, 5i02°TiO2
, Al2O3, Li2O, Na2O, Fe2O3, Cr
2O3゜ZrO2 based heater, sample/%13.14
The shape is 1oφHX 200'II, which is the same as this example.
It is m.

As is clear from Tables 2 and 3, the examples within the scope of the present invention are sample layers 1 to 46, and the others are comparative examples and conventional examples outside the scope. Samples within the scope of the invention exhibit low coefficients of thermal expansion, excellent moldability and excellent thermal shock properties. Moreover, sample layers 8 to 414 were outside the range and were conventional examples, and had poor thermal shock resistance, electrical properties, etc.

As described above, the composition within the scope of the present invention has excellent performance as a heating element, is extremely stable even in industrial mass production, and is of great industrial value.

Claims (1)

[Claims] One or two of Tic, TiN, WC, ZrC, and ZrN
・More than seeds・Total 38-80% by weight, eucryptite (Li20・Al2O3・2SiO2,): 18-60
weight%. Consisting of a range of components with a clayey substance content of 6% by weight or less, with a total of 1
1. A low thermal expansion heating element composition, characterized in that it is obtained by sintering a composition that has a composition of 0.00% by weight.