B4C has super hardness and extremely high wear resistance. In the uniform phase zone, the Vickers hardness of B4C increases with the increase of C content. When the carbon content is 10.6%, the hardness is 29.1GPa.When the carbon content is 20%, the hardness of 21 can reach 37.7GPa, and the hardness is still very high at high temperature (>;The change of hardness with temperature can be expressed by empirical formula (10).

H=H0-exp(-aT) (10)

Where: H0 is the hardness at room temperature

T - is the temperature

A - is the constant associated with the carbon content

This formula is applicable to 20 ~ 1700 need to point out is, B4C is one of the most hard materials in the world, second only to diamond and cubic BN B4C wear resistance increase with the rising of temperature, within the scope of the 20 ~ 1400, as the temperature rises, the friction coefficient decreased, at around 1400 down to 0.05, friction rate has been decreased B4C for its super hardness and friction characteristics have been used for spraying spit diamond nozzle and spray nozzle water jet cutter, such as wear-resistant materials;In military armored material such as tanks are widely used in aircraft (39, 40) with the progress of technology, the increasing demand for high precision grinding, 4 c, increasingly shows its superiority, in recent years, its usage has been increasing, at the same time, B4C can also be used to grinding hard alloy ceramic and stone hard qualitative material, friction with the free abrasive or ultrasonic machining these superhard abrasive material, but our country compared with Europe and the United States in this respect dosage were rare.