三维针刺C/SiC刹车材料的热物理性能

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

  • 摘要: 通过化学气相渗透(CVI)法结合反应熔体浸渗(RMI)法制备了三维针刺C/SiC刹车材料, 系统研究了三维针刺C/SiC刹车材料的热物理性能。结果表明: C/SiC刹车材料的热膨胀系数随温度升高总体呈增大趋势, 但呈规律性波动; 在相同温度下, 垂直于摩擦面方向的热膨胀系数远大于平行方向的。从室温至1300 ℃, 平行和垂直于摩擦面方向的平均热膨胀系数分别为1.75×10-6K-1和4.41×10-6K-1; C/SiC刹车材料的比定压热容随温度的升高而增大, 但增大速率逐渐减小。温度从100 ℃升到1400 ℃, 其比定压热容从1.41 J/(g·K) 增大到1.92 J/(g·K); C/SiC刹车材料的热扩散率随温度的升高而降低, 并趋于常量。平行于摩擦面方向的热扩散率明显大于垂直于摩擦面方向的热扩散率。

     

    Abstract: 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 ℃, 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 ℃ to 1400 ℃, 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.

     

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