To obtain silicon nitride of high α-phase content with a high nitridation percentage by using metallic iron and/or an iron compound and a silicon oxide as a catalyst, when a silicon nitride powder is produced by directly nitridation.
Iron and/or iron compound in an amount of 1 or more pts.wt., preferably 0.1-5 pts.wt., more preferably 0.2-1 pt.wt., a silicon oxide in an amount of 1 or more pts.wt., preferably 0.1-5 pts.wt. more preferably 0.2-1 pt.wt. are added to 100 pts.wt. of metallic silicon powder to effect direct nitridation of silicon. Iron and iron compound are, for example, oxides as FeO, Fe3O4 or Fe2O3, halides as FeF3 or FeCl3 or nitrates as Fe(NO3)2.6H2 O, but iron and iron oxide are preferred from the view points of decomposition and staining. The silicon oxide is, for example, SiO, SiO2 and the like, but SiO2 is preferred from view points of storage stability and cost.
SASAGAWA TADANOBU
KONYA YOSHIHARU
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