以航空发动机主轴轴承引导面与保持架之间的异常磨损为背景,研究了M50钢及M50钢表面沉积TiN涂层与保持架材料镀银层之间对磨时的摩擦特性,分析了干摩擦条件下相对滑动速度、接触应力及其交互作用对摩擦系数随时间变化的影响规律.采用SEM观察了摩擦表面的形貌,并用EDS对表面成分进行了分析.结果表明,摩擦系数随时间逐渐增大,存在明显的转变点;在低滑动速度和较低接触应力时,摩擦系数可以长时间维持在0.15～0.25较低水平,在较高滑动速度和较高接触应力时,摩擦系数很快上升到0.5左右,在试验选择的参数范围内,该转变时间与接触应力P和滑动速度V的乘积PV值基本上呈线性关系;高速大接触应力摩擦时,M50钢表面会受到硬质颗粒的作用产生划伤,而TiN涂层对M50钢具有良好的防护作用,可以明显延缓高摩擦系数出现的时间,阻止M50钢中碳化物脱落,防止表面磨损.%This work investigated the tribological properties of M50 steel and TiN coated M50 steel against silver coatings,based on the abnormal wear existing in aerospace engine bearing.The effect of relative sliding speed,contact stress as well as the interaction between the two parameters on friction coefficient with time were analyz.SEM and EDS were used to observe the surface morphology and the compositions of the wom traces.The results show that,friction coefficient increases with sliding time,and exists an abrupt change time.With lower sliding speed and lower contact stress,the friction coefficient keeps on 0.15-0.25.However,with higher sliding speed and higher contract stress,the friction coefficient rises quickly and reaches about 0.5.Within the range of parameters in this test,the change time has an approximate linear relationship with PV value,which is the product of contact stress P and sliding speed V.Sliding with high speed and high contact stress,the scratch will occur on the surface of M50 steel by the large hard particles.TiN coating can obviously postpone the time of the high friction coefficient,and has the advantage to prevent the worn of M50 steel due to impeding the peel off of the large carbides.
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