TC4合金微弧氧化膜的摩擦磨损性能及其失效机理研究

Investigation of Friction and Wear Performance and Failure Mechanism of PEO Coating on TC4 Alloy

采用微弧氧化(PEO)技术在TC4合金(Ti6Al4V钛合金)表面制备了微弧氧化耐磨陶瓷膜层.利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和摩擦试验机分析测试了微弧氧化膜的结构与组成,考察了膜层在干摩擦和油润滑条件下的摩擦磨损性能及其磨损失效机理.结果表明:基底材料的氧化和电解液化合物的沉积均对微弧氧化膜层的生长起重要作用;微弧氧化有效提高了材料的耐磨性,降低了材料在油润滑条件下的摩擦系数;在干摩擦条件下,摩擦力较大,剪切应力是导致膜层失效的主要因素,在油润滑环境中,压应力是导致膜层失效的主要因素;对微弧氧化膜层进行有效润滑可以极大地提高膜层的使用寿命.

Plasma electrolytc oxidation(PEO) wear resistant ceramic coating was prepared on TC4 alloy by using the pulsed bipolar power supply. The microstructure, phase composition, friction and wear properties under dry friction and oil lubrication environments as well as failure mechanism under different conditions were studied by using scanning electron microscope(SEM), energy dispersive spectrometer(EDS), X-ray diffraction(XRD) and a tribometer. It was found that the PEO coating on TC4 alloy was grown mainly by both the oxidation of the substrate and the deposition of electrolyte-borne compounds. The PEO coating greatly improved the wear resistance and decreased the friction coefficient of the material under oil lubrication environment. In non-lubricated environment, the friction force was larger, and the shear stress was the main factor for the failure of the coating. In lubrication environment, the compressive stress was the main factor leading to the failure of coating. Effective lubrication of the PEO coating could improve the wear lifetime of coating greatly.