PTFE基复合材料在干摩擦和液氮介质中的摩擦磨损性能研究
Friction and Wear Behavior of PTFE-based Composites under Dry Sliding and in Liquid Nitrogen
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摘要: 对比考察了聚苯酯(Ekonol)和PAB纤维增强PTFE复合材料在干摩擦和液氮介质中的摩擦磨损性能,利用扫描电子显微镜观察分析在干摩擦和液氮条件下Ekonol/PAB纤维增强PTFE复合材料的磨损表面形貌及其磨损机理,同时还考察了温度对复合材料冲击韧性的影响.结果表明:在液氮条件下,PTFE的抗犁削能力增强,Ekonol/PAB/PTFE复合材料的磨损量明显比干摩擦下低,复合材料的摩擦系数比干摩擦下大,载荷对复合材料的磨损量影响较小,复合材料的摩擦系数和磨损量随着滑动速度增加基本保持不变,材料的磨损机理主要为轻微犁削和脆性断裂;而在干摩擦条件下,载荷对复合材料的磨损量影响显著,随着滑动速度增加,复合材料的摩擦系数先增后减,磨损量逐渐增大,材料的磨损机理主要以犁削、粘着磨损及疲劳磨损为主.在2种试验条件下复合材料的摩擦系数均随载荷增加而减小;低温时材料的冲击韧性约为常温时的1/2.Abstract: Friction and wear behavior of Ekonol and PAB fiber reinforced PTFE composites under dry sliding and in liquid nitrogen were studied on MPX-200 wear tester.The morphologies of the worn surfaces and wear mechanisms of the PTFE composites after tests were observed and analyzed by scanning electron microscope(SEM).Effects of temperature on impact strength of composites were evaluated.The results showed that the anti-ploughing ability of PTFE increased in liquid nitrogen,wear mass loss of Ekonol/PAB/PTFE composites was much lower under low temperature than those at room temperature.The friction coefficient of composites at room temperature was much lower than that under low temperature.The load effect on wear mass loss of composites was small under low temperature.The friction coefficient and wear mass loss remain steady with sliding speed increased,the wear behavior was characterized by ploughing and brittle fracture.Under dry sliding,friction coefficient at the beginning increased and then decreased,while wear mass loss kept increasing,when sliding speed increased,load effect on wear mass loss of composites was prominent.Under the listed test conditions,when load was greater than 300 N,wear mass loss of composites went up sharply.The wear of Ekonol/PAB/PTFE composites was characterized by ploughing,adhesion and fatigue.At both room and low temperature condition,friction coefficient decreased with increasing load.The impact strength of Ekonol/PAB/PTFE composites at low temperature was about one second of that at room temperature.