电火花间隔沉积石墨-硬质合金自润滑涂层及其摩擦学性能

Tribological Properties of Self-lubricating Coating Prepared by ESD with Graphite and Cemented Carbide Alternately Deposited on Substrate Surface

目的提高机械零部件表面的润滑性能。方法以45钢为基体,采用电火花沉积技术在表面上间隔沉积出条状的石墨与硬质合金涂层条,用HSR-2M型高速往复摩擦磨损试验机对所制备的条状涂层进行相关的摩擦磨损试验,使用SEM和EDS并对涂层的表面形貌、截面形貌以及组成成分进行研究,分析了不同因素对石墨-硬质合金自润滑涂层摩擦磨损性能的影响规律及磨损机理。结果涂层表面致密,且厚度均匀,在与对偶件摩擦时表现出良好的自润滑性能及耐磨性能。随着硬质合金涂层所占面积比从10%上升到40%时,涂层的润滑性能会降低,耐磨性提高,但随着往复摩擦频率的增加,接触表面温度升高,变形阻力下降,自润滑性能有所提升。当往复摩擦频率为500次/min时,摩擦因数最小。结论石墨-硬质合金自润滑涂层的耐磨性和润滑性能与硬质合金在涂层区域中所占面积比及往复摩擦频率有关。主要是因为往复摩擦频率的增加会使磨粒的刻划作用增强,而硬质合金所占面积比会使涂层的硬度、耐磨性增加,涂层的主要磨损形式表现为磨粒磨损。

To improve the surface lubrication performance of mechanical parts.A strip of graphite and cemented carbide self-lubricating coating was deposited on 45 steel substrate by EDM.The friction and wear test of the prepared coating was carried out by HSR-2M high speed reciprocating friction and wear testing machine.The surface,section morphology and composition of the coating were studied using SEM and EDS.The influence of different factors on the friction and wear resistance performance of graphite cemented carbide self-lubricating coating and the wear mechanism were analyzed.The surface of the coating is compact with uniform thickness,which shows good self-lubrication and wear resistance when rubbing against the mating plates.As the area ratio of cemented carbide coating increases from 10%to 40%,the lubrication property of the coating will weaken and wear resistance will improve.However,with the increase of the frequency of reciprocating friction,the temperature of the contact surface increases,the deformation resistance decreases,and the self-lubrication property improves.When the frequency of reciprocating friction is 500 times/min,the friction coefficient decreases to a minimum value.The results show that the wear resistance and lubrication property of the self-lubricating coating are related to the area ratio of cemented carbide in the coating area and the frequency of reciprocating friction.The main reason is that the increase of the frequency will reinforce the abrasive effect,and the area ratio of cemented carbide will make the coating hardness and wear resistance increase.The main wear form of the coating is abrasive wear.