PRODUCTION OF A CERAMIC MATERIAL CONTAINING SILICON, ALUMINIUM, OXYGEN AND NITROGEN

摘要

A method of producing a ceramic material includes the step of heating at a temperature between 1200.degree. and 2000.degree.C a mixture containing silicon nitride in an amount up to 98% by weight of the mixture together with between 1% and 60% by weight of aluminium nitride, between 0.5% and 50% by weight of silica, and between 0.05% and 60% by weight of alumina, some but not all of the silica in the mixture at said temperature being present as an impurity contained by the silicon nitride. The silicon nitride, aluminium nitride, alumina and silica produce at said temperature a reactable composition which constitutes at least 95% by volume of the mixture and in which the silica is present in a molar ratio of 1:2 with part of the aluminium nitride and the alumina is present in a molar ratio of 1:1 with the remainder of the aluminium nitride, and the constituents of the reactable composition react together to produce the required ceramic material.