... the hardest materials known, ranking second behind diamond. Boron carbide is characterized as following,Extreme hardness,hardness 9.36. ... ,resistance gravity,2.52g/cm3, smelting point, 2450Centigrade.For its good properties and characters,it has wide applicationDue ... absorption of neutron.Other using: an indispensable material for making boric metal, for example, titanium boride, boric steel, etc, the ...