Tribological Behavior and Self-Lubrication Mechanisms of C_f/SiC-B₁₂(C,Si,B)₃ Composites Under Coupled...

To address the increasing demands for lightweight, high-temperature resistant braking materials under extreme service conditions, a novel C_f/SiC-B₁₂(C,Si,B)₃ composite was developed in this work. The composite was fabricated via a hybrid slurry infiltration-reactive melt infiltration (SI-RMI) process. The tribological performance under coupled temperature-velocity conditions was systematically evaluated using a ball-on-disk tester over temperatures from 25 to 600 °C (at 900 r/min) and sliding speeds from 300 to 900 r/min (at 600 °C). The results indicate that temperature dominates the friction and wear behavior. At room temperature, the composite exhibits a friction coefficient of 0.52 and a wear rate of 4.019 × 10^-4 mm³/(N·m). With increasing temperature, friction coefficients decreased to 0.43 at 400 °C and 0.41 at 600 °C, while wear rates increased sharply to 12.025 × 10^-4 mm³/(N·m) at 400 °C before declining to 5.228 × 10^-4 mm³/(N·m) at 600 °C. Under the fixed temperature of 600 °C, raising rotational speed from 300 to 900 r/min increased the wear rate only marginally (4.953 to 5.228 × 10^-4 mm³/(N·m)). Surface analysis indicates that a continuous Si-B-O oxide layer (mainly SiO₂ and B₂O₃) forms at 600 °C, which may provide solid lubrication and oxidation resistance. The present work offers a preliminary exploration of the tribological evolution and self-lubrication mechanisms of C_f/SiC-B₁₂(C,Si,B)₃ composites, providing potential insights for the design of advanced ceramic-matrix braking materials.