... melting point 24500c, 3.density 2.51g/cm3 Boron Carbide, a black powder, is the hardest of the conventional abrasives, Its ... no reaction with either acids or alkali etc. Boron carbide is widely used to grind and polish hard metal ... alloy, super-hard metal, high carbide steel, jewel, hard ceramic and other hard materials, ... 371 63691217Fax:+86 371 63691212 High Hardness Boron Carbide