| 摘要 |
PROBLEM TO BE SOLVED: To produce high-purity silicon nitride fine powder by a direct nitriding method. SOLUTION: A method for producing high-purity silicon nitride fine powder comprises the steps of: crushing machining scraps of high-purity silicon having≥10 m<SP>2</SP>/g specific surface area to obtain a fine powder raw material having≤1.1μm D50 (50% cumulative diameter) and≤4μm D90 (90% cumulative diameter); if necessary, mixing high-purity silicon nitride powder in the fine powder raw material; and placing/heating the (high-purity silicon nitride powder-mixed) fine powder raw material in an atmosphere including nitrogen gas or ammonia gas to react the particles thereof with one another at 1,300-1,700 highest temperature. It is preferable that a wet jet mill is used at the step of crushing machining scraps and the total of Fe, Al and Ca contained in the fine powder raw material obtained by the crushing is≤40 ppm. COPYRIGHT: (C)2011,JPO&INPIT |
