CERAMIC MATERIALS

摘要

A ceramic material includes at least 90% of a single phase compound in the form of a .beta.-phase silicon nitride lattice in which the silicon in the lattice has been partially replaced by aluminium and the nitrogen has been partially replaced by oxygen. The ceramic materials is produced by mixing not more than 75% by weight of high active surface area alumina in powder form of less than 10 microns, or a compound of aluminium which decomposes to give the required alumina at an elevated temperature with powdered silicon nitride of particle size less than 20 microns, and sintering the mixture at a temperature in the range 1550.degree.C to 2000.degree.C for at least 30 minutes to produce a ceramic material containing at least 90% of the above single phase compound.