HIGHLY FILLING SILICON NITRIDE POWDER AND ITS PRODUCTION

摘要

PURPOSE:To achieve a high temperature and low viscosity in slurrying, enable the increase in density of a molded body and thereby improve the strength or dimensional accuracy of a sintered compact. CONSTITUTION:Silicon nitride powder obtained by a direct nitriding method of metallic silicon powder having 1-10mum average particle diameter and >=99wt.% purity is pulverized with a dry stirring pulverizer until the tap density attains >=0.9g/cm<3> and the amount of existing particles having >=3 aspect ratio attains >=95%. Coarse particles having >=2mum particle diameter are then pulverized with a wet stirring pulverizer to afford the objective highly filling silicon nitride powder, having >=0.9g/cm<3> tap density and 0.4-0.6mum average particle diameter and containing >=95wt.% particles having <=3 aspect ratio and <=5wt.% particles having >=2mum particle diameter.