The capability of a material to withstand the action of heat devoid of appreciable deformation of softening is submitted to as refractoriness. Such property is measured as temperature at that the refractory material softens or fuses beneath several load.
The refractory are those materials that can withstand the action of hot environment, both gaseous and liquid. The industries engaged in manufacturing of chemicals, ceramics, metals and glass depend heavily on utilizing refractory materials. Most refractory materials are ceramics. Such are made up of high-melting oxides of Zr, Mg, Al, Ca and Si. There might be other elements represent as impurities. The present enhancement in high temperature applications has initiated crystalline oxides, sulfides, carbides and borides. That type of materials is sometimes combined along with metals to produce cermets that have better shock resistance than pure carbide or oxide refractories. The cermets are utilized in gas turbines, missiles, nuclear reactors, ran jet engines etc.