碳纤维长度与取向对纸基摩擦材料热负荷及摩擦学性能影响

采用湿法成型工艺制备了碳纤维长度为0.1~12 mm的5种碳纤维增强纸基摩擦材料.采用梯度能量试验方法测试了所制备材料承载热负荷的能力以及在各级能量负荷条件下的摩擦磨损性能.借助扫描电镜及热导率测试仪,研究了材料承载热负荷的机理.结果表明:碳纤维长度与取向对材料的热负荷及摩擦学性能有显著影响;当碳纤维长度为6 mm时,材料承载热负荷的能力最高;长度为3~12 mm的碳纤维能够在摩擦面形成稳固的框架结构,使材料在不同能量负荷条件下保持稳定的摩擦磨损性能;纤维长度对碳纤维在材料中的排列取向有直接影响,垂直于摩擦面排列的碳纤维能够显著提高材料的热导率并降低材料所承受的最大功率密度.

Effects of Carbon Fibers Length and Orientation on Thermal Load and Tribological Properties of Paper-based Friction Material

Five kinds of carbon fiber reinforced paper-based friction materials with 0.1 ~ 12 mm long carbon fibers were fabricated by paper-making process. The effects of carbon fibers length and orientation on thermal load and tribological properties were investigated by using a stepped power test method. Friction failure mechanisms were analyzed via combined use of the scanning electron microscope and thermal conductivity tester. The results show that the carbon fiber lengths and orientation had pronounced effects on thermal load capacity and tribological properties. The sample containing 6 mm long carbon fibers had the supreme thermal load capacity. Firm framework was set up by using 3~12 mm long carbon fibers as reinforcement, which guaranteed stable tribological properties under different power levels. Meanwhile, the carbon fibers length played an important role in fibers orientation. The thermal conductivity was improved and the max power flux was decreased when carbon fibers were perpendicular to friction surface.