Hardmetals and cermets

The ability to chose different components in a composite material introduces a new concept in materials science, i.e. the materials engineering or designing a new material by "compositing" two or more materials. Considering the use of ceramic materials, which is often limited by their low mechanical reliability, and the use of metals with their relatively low resistance to oxidation, abrasion and corrosion, high density and degradation of the materials properties at high temperatures, a composite materials were designed to perform a particular function. The metal provides complementary properties, so that the ceramic-metal system produces technological advantages impossible with ceramics or metal alone. Composite material has a combination of properties superior to those attained with ceramics or metals independently, or it has some other property not clearly shown by any of the component materials. The precursor of cermets are cemented carbides or hardmetals, usually based on WC. The term "cemented" is due to the fact that the carbide particles are "cemented" together by binder, usually a metal/alloy, which is liquid at the sintering temperature. These class of composites have been developed as cutting tool materials. The tungsten carbide free hardmetals or cermets have been developed as alternative materials to the classical WC-Co hardmetals. Cermets are a class of composite materials, which has over 70 years mainly applied for metal cutting purposes.