Sn-Ag-Cu自润滑滚子轴承的高温摩擦学特性

High Temperature Tribological Characteristics of Sn-Ag-Cu Self-Lubricating Roller Bearings

采用真空熔渗技术制备Sn-Ag-Cu高温自润滑滚子;在滚珠隔离式无保持架高温平面推力轴承试验装置上,对自润滑滚子轴承的高温摩擦特性进行试验研究;应用SEM/EDS技术分析轴承滚道摩擦表面的形貌和成分,研究试验温度、润滑剂合金与轴承滚动摩擦磨损之间的关系。研究表明:在400~600℃温度范围内,轴承的摩擦因数随着温度的的升高逐渐降低,当温度达到润滑剂合金熔点600℃时,摩擦因数达到最低值0.024;当温度为400℃时,轴承滚道摩擦表面以黏着磨损为主;随着温度升高,自润滑材料中的润滑剂合金逐渐析出涂覆在滚道表面,与滚道表面的高温氧化物共同影响轴承的摩擦学特性,因此在摩擦表面出现部分黏着磨损与氧化磨损;达到600℃后,滚道表面涂覆形成的润滑膜增多,因此氧化磨损和黏着磨损得到减轻,润滑效果最好。

The Sn-Ag-Cu high temperature self-lubricating rollers were prepared by vacuum infiltration technology,and the high temperature tribological characteristics of self-lubricating roller bearings were studied on a new type of high temperature plane thrust bearing which used a set of ball isolation bodies as a retainer.The morphology of the friction surface of the raceway and the wear scar composition were analyzed by SEM/EDS.The results show that the friction coefficient of bearing is decreased gradually with the increasing of temperature from 400 ℃ to 600 ℃,the friction coefficient reaches the lowest value of 0.024 when the temperature reaches lubricant alloy melting point of 600 ℃.When the temperature is 400 ℃,the main wear mechanism of bearing raceway friction surface is adhesion wear.As the temperature increases,the lubricant alloy in the self-lubricating material gradually precipitates and coats on the raceway surface,which affects the tribological characteristics of the bearing together with the high temperature oxides on the raceway surface,therefore,some adhesive wear and oxidation wear occur on the friction surface.When the temperature is 600 ℃,the lubrication film formed on the surface of raceway is increased,therefore the oxidation wear and adhesion wear are alleviated,and the best lubrication effect is realized.