Brinks Hofer Gilson & Lione
Process for producing silicon nitride sintered body for use in ceramic heater for use in glow plug
In the production of a silicon nitride sintered body through a hot press method, a sintering aid protecting agent is added to the raw material. The employable protecting agents are metallic elements such as Ta, W and Mo and compounds of the metallic elements such as nitrides and silicides. Conversion of these elements and compounds to carbides occurs preferentially to reduction of the sintering aid. Thus, it becomes possible to suppress reduction of the sintering aid in a reducing atmosphere formed, for example, of carbon monoxide, which is generated particularly when a graphite pressing die is employed.
NGK Spark Plug Co., Ltd.
C F C H F H H
C04B F23Q C04B H05B F23Q H05B H05B
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Shindo Masahiro
Watanabe Konishi