PROCESSES FOR PREPARING A BASE NITRIDABLE SILICON-CONTAINING MATERIAL AND SILICON NITRIDE MATERIALS

摘要

A process for preparing silicon for forming a ceramic precursor is disclosed which comprises comminuting the silicon particles in a mixture with water for substantial reaction with the water to provide a nitridable silicon-containing material. The silicon particles are present in the mixture from about 5 to about 99.5 volume percent and the water is present in the mixture from about 0.5 to less than 40 volume percent. A nitriding agent and/or a densification aid and/or inert matter may be admixed to the mixture either before or after comminuting. The reacted mixture may be dried and nitrided to form alpha-phase silicon nitride. If the mixture does not have a densification aid mixed therein, after nitriding, the resultant alpha-phase silicon nitride may be converted to a non-densified beta-phase silicon nitride by heating the resultant silicon nitride to a temperature of from about 1450 DEG C to about 2100 DEG C for a sufficient length of time to convert the alpha-phase silicon nitride. If the mixture has a densification aid mixed therein, after nitriding, the resultant alpha-phase silicon nitride may be sintered to a densified beta-phase silicon nitride by heating the alpha-phase silicon nitride to a temperature of from about 1450 DEG C to about 2100 DEG C for a sufficient length of time to convert the alpha-phase silicon nitride.