Silicon nitride/SiAlON ceramics —A review

36-45Advanced ceramic materials such as Si3N4 and SiAlON are reviewed here with particular reference to their synthesis, properties, and applications in various sectors such as transport and defense. It is noticed that synthesis by the simultaneous carbothermic reduction and nitridation (CTR) is relatively easy and economical. The products thus obtained by CTR, have unusual combination of unique properties, viz., high strength at higher temperature, chemical inertness, wear resistance, etc. , and therefore they are very much useful in high-tech areas. In addition, some of the leading manufacturers of Si3N4/SiAlON are listed in this paper. Ceramic whisker growth mechanism and its importance in improving the mechanical properties of ceramic matrix composites (CMCs) are also discussed. This paper is mainly intended to cover important properties like structural, mechanical, oxidation/corrosion and wear resistance of Si3N4 and SiAlON