Structural and thermostructural ceramics

Structural and thermostructural ceramics are the candidate materials for wear resistant, high temperature, aggressive environment engineering applications due to a combination of technologically attractive properties. The latter include: high melting point, hardness, refractory nature, low to moderate specific gravity, high elastic modulus, low coefficient of thermal expansion, moderate to high thermal conductivity, retention of strength at elevated temperatures, chemical, liquid metal and high temperature corrosion resistance, as well as ablation resistance. Structural ceramics are classified into five groups based on their chemistry, viz. oxides, carbides, nitrides, borides and silicides. As for metals and alloys, in ceramics the microstructure and mechanical properties are interrelated with each other. Microstructure thus plays a crucial role and is governed by the characteristics of the starting powder and densification method. Starting powder characteristics can be tailored by the synthesis method, which can be selected based on the end use requirement. This article reviews the synthesis, consolidation, microstructure, mechanical, physical and thermal properties and applications of structural and thermostructural ceramics.