SILICON NITRIDE MATERIAL AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED : To provide a silicon nitride material having a sintering aid element which is necessary to obtain a silicon nitride ceramic material excellent in high temperature strength and which uniformly covers the surface of entire particles, and to provide a method for manufacturing the material. SOLUTION : The silicon nitride material has a water-insoluble metal compound which contains at least one element selected from rare earth elements, alkaline earth elements and Al and which covers the surface of the entire particles of silicon nitride by ≥0.1 wt.% to <10 wt.% in terms of oxides. The particle surface of the silicon nitride material is highly covered with the sintering aid element. A sintered body produced from the above material as the source material has uniform distribution of intergranular phases and significantly excellent high temperature strength, and therefore, it can be used for various kinds of heat-resistant parts.