Refractoriness

The ability of a material to withstand the action of heat without considerable deformation of softening is referred to as refractoriness. This property is measured such as temperature at which the refractory material softens or fuses under some load.

The refractories are those materials which might withstand the action of hot environment, both liquid and gaseous. The industries engaged in manufacturing of metals, glass ceramics and chemicals depend heavily upon utilizing refractory materials. Most of refractory materials are ceramics. They are built up of high-melting oxides of Si, Al, Mg, Ca and Zr. There might be other elements present as impurities. The present development in high temperature applications has introduced carbides, crystalline oxides, borides & sulfides. Such materials are sometimes combined along with metals to generate cermets which have better shock resistance than pure oxide or carbide refractories. The cermets are utilized in gas turbines, missiles, ran jet engines,  nuclear reactors etc.