GF/PTFE自润滑纤维复合材料磨损性能热衰退研究

针对高频摆动关节轴承摩擦热对自润滑纤维复合材料摩擦磨损性能的影响，研制了高频使用条件下的玻璃纤维增强聚四氟乙烯(GF/PTFE)自润滑纤维复合材料，利用MYB～500高频高载摆动摩擦磨损试验机，对其进行不同摩擦温度下的摩擦磨损性能测试，研究摩擦热作用下材料自润滑性能和磨损性能衰退特征，分析磨损产物和摩擦表面以及不同摩擦温度下材料的磨损机理。结果表明，摩擦热对材料自润滑性能影响显著，适当的摩擦温度范围能够保证材料的自润滑性能，摩擦温度和摩擦因数之间互为耦合作用，对材料的磨损性能具有一定的影响；高摩擦热作用于自润滑过程及机理的改变，造成材料的磨损性能衰退现象。因此，不同温度下材料的磨损特征具有明显的差异化，其中低摩擦温度下(60～120℃)材料自润滑性能优异，磨损率很低；140℃摩擦温度条件下材料摩擦磨损性能开始衰退；材料在高摩擦温度下(140～180℃)的磨损初期自润滑性能良好、磨损轻微，而中后期磨损严重。微观分析表明，低摩擦温度下材料的磨损机理以轻微粘着和疲劳磨损为主；高摩擦温度下材料的磨损以片状剥落、纤维剪切破坏为主，且磨损面局部损伤特征明显，磨损严重。

Study on Thermal Degradation of Wear Properties of GF/PTFE Self-lubricating Fiber Composites

For high frequency oscillating spherical plain bearing, friction heat has significant effect on friction and wear properties of the self-lubricating fiber composites. The glass reinforced polytetrafluoroethylene (GF/PTFE) self-lubricating fiber composites are developed for high frequency service condition, and a MYB-500 high frequency and high load oscillating tribological tester is used to carry out tribological tests of the composites under different friction temperatures. The self-lubricating performance and wear behavior of material under friction heat are investigated, and the wear debris and friction surface and wear mechanisms under different temperatures are analyzed. Results show that, friction heat has notable influence on self-lubricating performance of the composites. Proper friction temperature is beneficial to improve the self-lubricating performance of the material, and the interaction between friction temperature and friction coefficient has a certain effect on wear behavior of the material. High friction heat acts on the self-lubricating process and mechanism, resulting in degradation of material wear properties. Therefore, wear behavior of the composite is different under different friction temperature. The self-lubricating performance under low friction temperature(60-120 ℃)is the best and the wear rate is the lowest. The degradation of friction and wear performance of the composite occurs until it reaches to 140 ℃. Under high temperature(140-180 ℃), the material initially has good self-lubricating performance and slight wear, whereas it becomes worse in the middle and late stage. Micro analysis shows that, the wear mechanism of the material at low friction temperature is mainly slight adhesion and fatigue wear. At high friction temperature, the wear of the material is mainly characterized by a large number of adhesion and flaking off, and the material surface has obvious local damage with serious wear.