Silicon Nitride and Sialon Ceramics—A Review

Silicon nitride and sialon ceramics are receiving a great deal of attention as potential high temperature structural materials for engines and other demanding applications. The sintering behaviour and high temperature preformance of these ceramics is strongly influenced by the sintering additives, impurities and powder characteristics of the starting material. Careful control of these parameters and the use of post-sintering heat treatment of the densified ceramics can lead to significant improvements in properties such as high temperature strength, oxidation and creep resistance. In order that these ceramics can become commercially viable further research is still required in such areas as the interaction between fabrication, phase equilibria, composition, microstructure and properties as well as the development of methods of producing cheaper starting powders.