La synthèse des poudres céramiques non-oxydes par réduction carbothermique

Non-oxide ceramic powder synthesis by carbothermal reduction

Ingénieur au Centre de recherche Rhône-Alpes Atochem

Abstract

Facing the problem of developping an industrial process to make non-oxide ceramic powders, the following main criteria must be considered ;

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  the availability of raw materials, their cost and their grades (especially purity) ;

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  the energy consumption for the realization of the transformations ;

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  the versatility of the process that is to say its ability to yield various products and for each of them several grades (fineness, specific area...) ;

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  the ability to operate continuously in order to assure reliability of the production and to envisage better cost effectiveness with large scale production when the market grows.

The consideration of these criteria has lead Atochem to the development of a process based on the carbothermal reduction of oxides, which produces first of all aluminium and silicon nitrides. This familiar process, refurbished with present technology and with the raw materials now available, allows the production of a range of powders with, for example, various specific areas. These powders are also characterized by X-ray diffraction. A continuous pilot plant will be operating in 1987