... 2.melting point 24500c, 3.density 2.51g/cm3 Boron Carbide, a black powder, is the hardest of the conventional abrasives, Its ... metal alloy, super-hard metal, high carbide steel, jewel, hard ceramic and other hard materials, to manufacture wear-resisting parts, ... additive for compound materials for military planes and as raw materials for matal boride, metal ceramic, boron steel, boron alloy and for ...