Cermets

(ceramals), heterogeneous compositions of metals or alloys with one or more ceramic phases of relatively low mutual solubility.

Cermets combine the properties of ceramics (great hardness, resistance to wear, refractoriness, heat resistance) and metals (thermal conductivity and ductility). The ceramic components include oxides (Al₂O₃, Cr₂O₃, SiO₂ and ZrO₂), carbides (SiC, Cr₃C₂, and TiC), borides (Cr₃B₂, TiB₂, and ZrB₂), suicides (MoSi), and nitrides (TiN); the metallic components include chromium, nickel, aluminum, iron, cobalt, titanium, and zirconium and the alloys based on them. The ceramic phase content varies from 15 to 85 percent (by volume). Articles are produced by the methods of powder metallurgy, that is, by compacting the powder blanks and then sintering in a reductive or neutral atmosphere. Cermets are used in the form of hard alloys in manufacturing parts for turbines and airplane engines and in producing friction parts, tools, and other articles that are subject to increased loads while operating in aggressive media and at high temperatures.