Hard carbide for mechanical sealing is the most widely used in cobalt-based tungsten carbide,It is made of extremely high hardness of tungsten carbide (WC) with cobalt (Co) or other iron group metals as a binder,Suppress and sintering by powder metallurgy method.The biggest characteristic is the high hardness、high thermal conductivity and a low coefficient of line expansion.WC and other hard phases in carbide alloy have strong corrosion resistance,It is very stable in corrosive media such as acid and base.However, the corrosion resistance of the bonding metal is poor,Often the sealing medium will first bond to the metal corrosion,Make the hard phase WC isolated and lose dependence,quickly worn off in relative friction.Therefore, WC-Co carbide carbide is not suitable for corrosive situations.But, it has strong corrosion resistance in media such as sulfuric acid and caustic soda below the boiling point at the general temperature.

　　WC-Co material has low impact toughness and high brittleness,machinery processing price is expensive,The physical and mechanical behavior carbide are as follows: