zirconium carbide

Chemical properties

dark gray brittle solid; cub, a=0.46983 nm; it is not a fixed stoichiometric compound; hard, high melting carbide used in UC-fueled reactors; enthalpy of fusion 79.4kJ/mol; hardness 8+ Mohs; used as a hot pressed crucible to melt metals such as bismuth, cadmium, lead, tin and high melting point oxides such as ZrO2, and as a 99.5% pure sputtering target to produce wear-resistant and other films [KIR84] [HAW93] [CER91] [JAN71]

Chemical properties

Zirconium carbide , nominally ZrC, is a dark gray brittle solid. It is made typically by a carbothermic reduction of zirconium oxide in a induction-heated vacuum furnace. Alternative production methods, especially for deposition on a substrate, consist of vapor-phase reaction of a volatile zirconium halide, usually ZrCl4, with a hydrocarbon in a hydrogen atmosphere at 900–1400 °C (1652–2552 °F).

Physical properties

Gray metallic solid; cubic structure; very hard, hardness > 8.0 Mohs; density 6.73 g/cm³; melts at 3,532°C; insoluble in water; slightly soluble in concentrated sulfuric acid; soluble in hydrofluoric acid and oxidizing acids, such as nitric and perchloric acids; attacked by oxidizers.

Physical properties

Dark gray brittle solid, soluble in HF solutions containing nitrate or peroxide ions. UC-nuclear power reactor, crucible container for handling molten metals such as Bi, Cd, Pb, Sn, Rb, and molten zirconia ZrO₂. Corroded by liquid metals Mg, Al, Si, V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ni, and Zn. In air oxidizes rapidly above 500°C. Maximum operating temperature of 2350°C in helium.

The Uses of zirconium carbide

Zirconium carbide is a refractory material. It is used in making incandescent filaments, high temperature electrical conductors, and cutting tool components.

Preparation

Zirconium carbide is prepared by heating a mixture of zirconium oxide and coke in an arc furnace.