La2O3对铜基自润滑复合材料高温摩擦磨损性能的影响

为进一步提高铜基自润滑复合材料的硬度和高温摩擦磨损性能,采用粉末冶金热压法向铜-石墨烯-WS2复合材料中引入La2O3增强相颗粒,并对铜-石墨烯-WS2复合材料和La2O3增强铜-石墨烯-WS2复合材料在不同温度下的摩擦磨损性能进行对比研究。结果表明:复合材料烧结过程中各组元没有发生分解或互相反应,烧结后材料结构致密并且各组元均匀分布于基体中,La2O3增强相的引入在提高复合材料硬度的同时会降低材料热导率;室温下2种复合材料摩擦因数和磨损率比较相近,而高温下石墨烯和WS2的氧化导致Cu-RGO-WS2复合材料摩擦磨损性能下降,而La2O3则能发挥增强相作用和高温自润滑作用,使Cu-RGO-WS2-La2O3复合材料的高温摩擦磨损性能更优异。室温下铜-石墨烯-WS2复合材料的磨痕处仅发生了轻微的塑性变形,而La2O3增强铜-石墨烯-WS2复合材料的磨损机制主要是磨粒磨损;高温下铜-石墨烯-WS2复合材料的磨损机制为黏着磨损,而La2O3增强铜-石墨烯-WS2复合材料的磨损机制则为磨粒磨损和疲劳磨损。

Effect of La2O3 on High Temperature Friction and Wear Properties of Copper-based Self-lubricating Composites

In order to further improve the hardness and high temperature friction and wear properties of copper-based self-lubricating composites,La2O3 particles were introduced into the Cu-graphene-WS2 composite by powder metallurgy hot-press sintering method.The friction and wear properties of Cu-graphene-WS2 composite and La2O3 reinforced Cu-graphene-WS2 composite at different temperatures were obtained.The results show that the component in the composites does not decompose or react with each other and is distributed uniformly in the matrix after sintering.The structure of the composites is relatively dense,the addition of La2O3 reinforcing phase can improve the hardness and reduce the thermal conductivity of the composites.At room temperature,the friction coefficient and wear rate of the two composites are similar.At high temperature,friction and wear properties of Cu-graphene-WS2 are decreased duo to the oxidation of graphene and WS2,while La2O3 reinforced Cu-graphene-WS2 composite has better high temperature friction and wear properties because La2O3 plays the role of reinforcing phase and high-temperature self-lubricating.At room temperature,only plastic deformation occurs at the worn surface of Cu-graphene-WS2 composite,while the wear mechanism of La2O3 reinforced Cu-graphene-WS2 composite is mainly abrasive wear.At high temperature,the wear mechanism of Cu-graphene-WS2 composite is adhesive wear,and the wear mechanism of La2O3 reinforced Cu-graphene-WS2 composite is abrasive wear and fatigue wear.