Friction and Wear Properties of MoSi₂-Mo₅Si₃-Mo₅SiB₂ Composite against SiC

MoSi₂-Mo₅Si₃-Mo₅SiB₂ composite is a promising wear resistance material at elevated temperature. However, the tribological properties of MoSi₂-Mo₅Si₃-Mo₅SiB₂ against SiC were not fully understood. In the present study, the friction and wear properties of the composite at 25~1 000 ℃ and 2.5~10 N were investigated using a ball-on-disk sliding tests. The results show that both test temperatures and applied loads had significant effect on the coefficient of friction (COF), while have insignificant effect on the wear rate. The COFs and wear rates of the MoSi₂-Mo₅Si₃-Mo₅SiB₂ composite at 25~1 000 ℃ were in the ranges of 0.11~0.43 and 0.540×10^-7~0.547×10^-7 mm³/(N·m), respectively. The mild oxidation and adhesive wears were main wear mechanisms for the composite tested below 400 ℃. At 600 ~ 1 000 ℃, the wear mechanisms were dominated by severe oxidation wear and adhesive wear. The COFs and wear rates of the composite, at 1 000 ℃ under load of 2.5~10 N, were in the ranges of 0.29~0.38 and 0.540×10^-7~0.547×10^-7 mm³/(N·m), respectively. The dominant wear mechanisms of the composite at 2.5~10 N were adhesive wear and oxidation wear, and accompanied with plastic deformation at 7.5~10 N.