Tribological performance of B ₄ C modified C/C-SiC brake materials under dry air and wet conditions

In this work, boron carbide (B ₄ C)was selected as additive to improve the tribological performance of C/C-SiC brake materials. It contained four phases (C, B ₄ C, Si and SiC)in B ₄ C modified C/C-SiC (C/C-B ₄ C-SiC)brake materials. Its wear rates were much less than that of C/C-SiC, especially at high braking speeds. The introduction of B ₄ C particles could reduce the braking temperature. During the braking process, B ₄ C in the material can be oxidized to B ₂ O ₃ . The flow of B ₂ O ₃ could cover the interface of carbon fiber and PyC to prevent them from oxidation and thereby reduce the oxidative wear of the brake materials. Under wet conditions, the braking property of C/C-B ₄ C-SiC brake materials did not degrade, whereas the braking process was found to be stable.