Process for sintering silicon nitride articles

摘要

A process for sintering silicon nitride articles to a density greater than 98% of theoretical density comprises the steps of heating a silicon nitride article in a covered container to a temperature equal to or greater than the liquidus temperature of the sintering aids contained in the silicon nitride article in a protective atmosphere and at a pressure for a period of time sufficient to obtain a density greater than 98% of theoretical density. The pressure is changed during the sintering step to displace the protective atmosphere in the closed container.