Graphite-zirconium carbide combined heat-generating body and preparation method thereof

Abstract

The invention relates to a graphite-zirconium carbide combined heat-generating body and a preparation method thereof. The graphite-zirconium carbide combined heat-generating body is formed by connecting two cold ends with a hot end, wherein the hot end is made of graphite, each cold end is formed by sintering and molding zirconium carbide, graphite and a sintering aid, the additions in percentage by weight of zirconium carbide, graphite and the sintering aid are as follows: 50-99% of zirconium carbide, 0-44% of graphite and 1-6% of sintering aid. According to the combined heat-generating body, since the resistance of zirconium carbide composite ceramic is relatively small, the zirconium carbide composite ceramic is difficult to heat when a large current is switched on, a cooling device can be saved and the energy consumption can be significantly reduced; meanwhile, the problems of relatively large volume and easiness in heat generation caused by an electrode made of only graphite are avoided and the problem of large difficulty in manufacturing and processing due to the zirconium carbide composite ceramic separately serving as the heat-generating body is also overcome; and the graphite-zirconium carbide combined heat-generating body can provide a high temperature above 2000 DEG C under vacuum or provides 2500 DEG C high temperature under a reducing atmosphere.

Description

technical field [0001] The invention relates to the technical field of electric heating materials, in particular to a graphite-zirconium carbide combined heating element and a preparation process thereof. Background technique [0002] Graphite, dark gray, soft, greasy, melting point 3652°C, density 2.25g / cm 3 , resistivity 5~13×10 -6 Ω m, hardness 1.5, thermal conductivity 129 W (m K) -1 , In air or oxygen, it starts to oxidize at 450°C. As a high-temperature and ultra-high-temperature material, it is often used as a high-temperature heating element, a high-temperature heat shield, a melting electrode, and a crucible. [0003] The main features of graphite heating element: (1) Good high temperature strength, the strength of graphite is far worse than that of metal at room temperature, but with the increase of temperature, its strength gradually increases. (2) Graphite has certain characteristics of metal and ceramics, and has good thermal conductivity and electrical condu...

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Problems solved by technology

[0005] In the existing graphite heating element, the electrode material and the heating end are all graphite. In order to reduce the heating of the electrode while ensuring the heating efficiency, the method of increasing the electrode size is often adopted. However, the multiple of the electrode size increase is limited. When a large current passes through the electrode, the electrode will still generate heat. In order to reduce the electrode temperature, it is necessary to add a cooling device to cool the graphite electrode, resulting in a complex structure of the electric furnace; The heat energy mainly comes from the energy conversion generated by high current, and the energy consumption increases

Zirconium carbide composite ceramics have high hardness. When used as a heating element, it is more difficult to manufacture and process, especially making large-scale heating elements is more difficult and costly, which severely restricts its application.

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