光学原位观测不同粉末层厚度的润滑层宏微观特性及分析

Optical in-situ observation and analysis of macro and micro characteristics of lubrication layers with different powder thickness

采用直线往复式原位观察试验机,分析30个行程中粉末层厚度对界面磨损状况、摩擦特性和真实接触面积比的影响。对试验后表面进行电子显微镜观察、能谱元素含量及三维轮廓分析,获得粉末层厚度影响摩擦特性的现象和机制。研究得出以下结论:粉末层厚度为1.5μm时,试件表面粉末层覆盖较薄,试件部分区域微凸体初始裸露,未形成较好粉末润滑膜,主要承载为微凸体接触承载,出现严重磨痕,初始真实接触面积比为11.17%,最终降低到20.14%;4.5μm时粉末层完全覆盖区域形成较好润滑膜,最终润滑膜完全剥落,平整性和承载降低;6μm时粉末层完全覆盖接触区域,形成完整润滑膜,平整性较好,基本为粉末层承载且无划痕,承载先增大到6 N后减小到2 N,微凸体承载2 N占总承载的33%,而粉末层摩擦力占比大于70%,真实接触面积比保持在60%以上。表明粉末层厚度为6μm时,粉末平整性好且碳元素含量高,接触充分、润滑效果良好。

Based on the linear reciprocating in-situ observation tester,the effects of powder layer thickness on in-terface wear condition,friction characteristics and real contact area ratio in 30 strokes were analyzed.The results show that thickness of powder layer is 1.5μm,the powder layer is relatively thin on the surface of specimen.Asper-ities in some areas is initially exposed,and powder lubrication film is not formed.Main load is the contact load of asperities and serious wear marks appear.The initial real contact area ratio is 11.17%and finally decreases to 20.14%.The powder layer is 4.5μm that the good lubrication film is formed in the area completely covered by the powder layer,and finally the lubrication film is completely peeling off and load is reduced.The powder layer is 6um that powder layer completely covers the contact area and form complete lubrication film,load of powder layer is dominant and there is no scratch.Load first increases to 6 N and then decreases to 2 N,and asperities bearing ca-pacity 2 N accounts for 33%of the total load.Friction ratio of powder layer is more than 73.3%and the real con-tact area ratio remains above 60%.The results shows that powder layer thickness is 6μm that the powder has good flatness,high carbon content,full contact and good lubrication.