Thermal physical properties of 3D needled C/SiC brake materials

The 3D needled C/SiC brake materials were prepared by chemical vapor infiltration (CVI) combined with reactive melt infiltration (RMI) method. The thermal physical properties of the 3D needled C/SiC brake materials were systematically investigated. The results indicate that the thermal expansion coefficients (CTE) of the C/SiC brake materials increase with the temperature increasing, but it shows regular fluctuation. At the same temperature, the CTE perpendicular to friction surface is far bigger than that parallel to friction surface. From room temperature to 1300°C, the average CTE parallel and perpendicular to friction surface are 1.75×10^-6 K^-1 and 4.41×10^-6 K^-1, respectively. The specific heat capacity of the C/SiC brake materials increases with the temperature increasing, but the rate of the specific heat capacity rise decreases gradually. From 100°C to 1400°C, the specific heat capacity increases from 1.14 J/(g·K) to 1.92 J/(g·K). The thermal diffusivity of the C/SiC brake materials decreases to constant with the temperature increasing. The thermal diffusivity parallel to friction surface is obviously larger than that perpendicular to friction surface.