... 2.27g/cm , Mohs value is 2, they have a high melting point(sublimate point is 3000°C). ... is between 2.0×10 /°C to 6.5×10 /°C. They have a high quality of heat-resistance and ... is poor, and their chemical properties are stable, they have a high corrosion-resistance of acid, alk, molten metal ... and glass. BN products cannot have chemical reaction with most molten metals, such as Cu, ...