LOW-OXYGEN SILICON GRANULE, ITS PRODUCTION AND PRODUCTION OF SILICON NITRIDE

摘要

PROBLEM TO BE SOLVED: To produce low-oxygen silicon granules capable of efficiently producing silicon nitride having a high ratio ofα-silicon nitride by direct nitriding and to produce silicon nitride using the low-oxygen silicon granules. SOLUTION: Silicon powder having 4-10μm average particle diameter is mixed with an org. binder and granulated and the resultant granules are heated at 1,300-1,400 deg.C for 0.5-5hr in a hydrogen-contg. inert atmosphere freed of nitrogen to produce the objective low-oxygen silicon granules having >=0.5m<2> /g specific surface area, <=0.4wt.% oxygen content and <1wt.% carbon content. The low-oxygen silicon granules are nitrided in a hydrogen-contg. nitrogen atmosphere to produce the objective silicon nitride.