(华南理工大学 材料科学与工程学院，广州 510640)
摘 要: 在硅酸钠电解质体系中，采用电流密度100 A/m2的非对称交流脉冲电源模式处理AZ91镁合金，在其表面获得均匀的陶瓷涂层。采用M2000磨损试验机研究了该涂层合金的干式滑动摩擦磨损行为。采用X射线衍射仪和扫描电镜对陶瓷涂层结构和磨损表面进行观察分析。结果表明：根据载荷大小，涂层处理后AZ91D镁合金的磨损行为明显分为3个阶段，这些阶段同陶瓷层是否磨穿密切相关；微弧氧化涂层AZ91D镁合金的磨损机理主要是磨粒磨损；受表面状况的影响，陶瓷涂层的摩擦因数在 0.20~0.45 间波动；在较高载荷下，涂层被磨穿后，涂层的摩擦因数趋于基体合金的摩擦因数，涂层合金的表面变形能力提高，该阶段质量磨损速率随载荷增加，趋势变得缓慢。
关键字: AZ91D镁合金；微弧氧化；陶瓷涂层；摩擦磨损
micro-arc-oxidation coating
（School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:Using an asymmetric alternative pulse current (AC) source and in silicate solution electrolyte, a uniform coating on the surface of AZ91D alloy was fabricated by micro-arc oxidation(MAO) with current density of 100 A/m2. The dry sliding wear behavior of this coated AZ91D alloy was performed on M2000 tribological machine. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to identify the phases and microstructures of coating and worn surface. The results show that in the applied load range of 10−250 N, the mass loss rate of coated AZ91D alloy can be identified to three stages, which are related with whether the coating is worn out. Abrasion is the main mechanism for the coated alloy. The friction coefficient (μ) of the coated alloy during sliding wear appears oscillation before it reaches a constant value, which is close to the μ value of the matrix alloy. The mass loss rate of coated alloy increases slightly with increasing applied load when the applied load is more than 150 N because of high plastic deformation accommodation on the matrix alloy surface.
Key words: AZ91D Mg alloy; micro-arc oxidation; ceramic coating; sliding wear
