SINTERABLE CERAMIC POWDER, PROCESS FOR ITS PREPARATION, SILICON NITRIDE CERAMIC MANUFACTURED THEREFROM, PROCESS FOR ITS MANUFACTURE AND ITS USE

摘要

The invention relates to a novel sinterable ceramic powder, to its preparation, to its processing to form silicon nitride ceramic and to said material itself and its use. The sinterable ceramic powder is prepared by dissolving the polysilazane of formula (I) [CH3SiHNH]n[CH3SiN]n where n is about 10 to 12, in an organic solvent, suspending a pulverulent sinter aid in this solution and then evaporating the solvent and pyrolyzing the residue in an inert gas atmosphere at 500 DEG to 1600 DEG C. The resulting ceramic powder can be used to form a shaped article and then to manufacture silicon nitride ceramic by sintering. It is also possible, however, to form a shaped article from the as yet unpyrolyzed residue obtained after evaporation of the solvent, and then to pyrolyze and sinter said article. The ceramic obtained can be used to manufacture components subject to high mechanical, thermal and corrosive stress.