Preparation and Dynamometer Tests of 3D Needle-Punched C/C-SiC Composites for High-Speed and Heavy-Duty Brake Systems

Three-dimensional (3D) needle-punched C/C-SiC brake composites were fabricated by chemical vapor infiltration combined with liquid silicon infiltration. The microstructures, properties, and dynamometer tests for different high-speed and heavy-duty brake systems had been investigated. The results indicated that the value of flexural strength and compressive strength can reach 182 Mpa and 234 MPa, respectively. Their thermal conductivity remained between 15-21 W/m/K between room temperature and 1100 degrees C. The dynamometer test of 3D needle-punched C/C-SiC brake disk and pads for high-speed trains, according to the procedure of International Union of Railways, showed that the coefficient of friction (mu) was about 0.32 and not sensitive to the brake speeds. After four times of emergency stops, the linear wear rate of the C/C-SiC pads was 0.481 cm(3)/MJ. The C/C-SiC brake pairs of vehicle were tested with inertia dynamometer according to SAE's J2522 testing procedure, and the characteristic values of the C/C-SiC brakes indicated that the hot fade was almost 0. The C/C-SiC pads were matched with C45 steel disk and tested for engineering machineries brake system, and the wear rate of C/C-SiC pads was 4.2 mu m/cycle and less than one-sixth of that of the traditional powder metallurgy brake pad. The 3D needle-punched C/C-SiC brake composites have been demonstrated to be the top choice for advanced friction materials of high-speed and heavy-duty brake systems.