Phase equilibria in the W–C system and tungsten carbides

The results of experimental and theoretical investigations of phase equilibria in the W–C system and of the crystal and electronic structures of tungsten carbides are generalised. The phase diagram of the W–C system supplemented by new compounds is considered. The sequence of phase transformations associated with ordering of lower hexagonal carbide β-W2C is analysed. The region of existence of cubic carbide γ-WC1–x is discussed in detail. The generalised information on the phase equilibria in the ternary system W–Co–C, which forms the basis for the synthesis of hard alloys WC–Co, is given. Methods of synthesis of tungsten carbides and hard alloys based on them are considered. Modern methods for the synthesis of nanostructured hard alloys are discussed in detail as well as their structures and properties.