纳米高岭土增强PTFE复合材料的摩擦磨损特性

采用纳米高岭土颗粒增强聚四氟乙烯(Po lytetrafluoroethy lene,PTFE),通过熔融插层工艺,制备了不同重量分数的纳米高岭土增强PTFE自润滑复合材料,摩擦磨损实验在往复式滑动摩擦实验机上进行。实验条件:接触压力为5.5M Pa,往复频率为1 H z,往复行程为1.5 mm。实验结果表明:在重载低速的条件下,这种新型的自润滑材料在稳定阶段的摩擦因数在0.07~0.19的范围,填充后的PTFE复合材料的耐磨性显著提高,其中含10%高岭土的PTFE复合材料的表现最佳,比纯PTFE提高了大约54倍。纳米高岭土提高PTFE耐磨性的主要原因是:其层片结构间被PTFE分子链插入,达到了增强基体并阻止PTFE成片剥落的目的。

Friction and Wear Properties of PTFE Composites Reinforced with Nano Particle Kaolin

Polytetrafluoroethylene(PTFE) and PTFE composites containing the various weight proportions of nano-particle Kaolin are prepared by the melt intercalation technique.Fiction and wear tests are carried out in a reciprocating sliding tribometer under contact pressure of 5.5 MPa,a reciprocating frequency of 1 Hz and a stroke distance of 1.5 mm.Results show that the novel self-lubricating composite against a mating 45 carbon steel track exhibites low coefficient of friction ranging from 0.07 to 0.19 during the steady-state sliding action,and the highest wear resistance is found for PTFE 10%(weight) Kaolin composite.Comparing with the unfilled PTFE,the wear resistance of the PTFE 10% Kaolin composite improves about 54 times.The major cause for enhancing wear resistance of the PTFE composite is that the samdwich of the nano-particle Kaolin is intercalated by chain linear molecules of PTFE,thus preventing the separation of wear fragments from the matrix.