触变成形AZ91D镁合金表面微弧氧化陶瓷层滑动摩擦磨损性能的研究
Study on Sliding Friction and Wear Properties of Micro-arc Oxidized Ceramic Coating on Thixoformed AZ91D Mg Alloy Surface
李 炳1,2, 张淑萍1,2, 马 颖2
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作者单位：1. 广东科技学院 机电工程系, 广东 东莞 523083; 2. 兰州理工大学 甘肃省有色金属新材料省部共建国家重点实验室, 甘肃 兰州 730050
中文关键字：触变成形镁合金； 微弧氧化； 磨损机制
英文关键字：thixoformed magnesium alloy; micro-arc oxidation; wear mechanism
中文摘要：在以Na2SiO3为主体的电解液中， 利用微弧氧化技术在触变成形AZ91D镁合金表面原位生长出厚60～65 μm的膜层，用UMT-2MT型球-块往复式摩擦试验机对膜层的干滑动磨损行为进行了研究。用SEM、XRD分析了微弧氧化陶瓷层磨损前后的表面形貌和相组成。结果表明：微弧氧化膜层是由Mg2SiO4、Mg、MgO、MgO2和Al3.16Mg1.81组成的陶瓷层；在滑动磨损过程中，随着载荷的增大，摩擦系数先增大后减小，磨损率则先缓慢增长后迅速增长；随着频率的增加，摩擦系数逐渐降低，磨损率先上升后缓慢下降，磨损机制由微切屑磨损向磨粒磨损转变。
英文摘要：A in-situ coating with the thickness of 60～65 μm was formed on the surface of thixoformed AZ91D alloy by micro-arc oxidation in a electrolytic solution of Na2SiO3. The friction and wear properties of the coating were investigated on a UMT-2MT reciprocating sliding wear apparatus (ball-on-block (disk)) under dry condition. The phase constitutes and morphology of the coating were analyzed using SEM and XRD. The results show that the coating is a ceramic coating composed of Mg2SiO4, Mg, MgO, MgO2 and Al3.16Mg1.8. The friction coefficient firstly increases and then decreases with the increase of load, while the wear rate firstly increases slowly and then increases sharply. And the friction coefficient decreases with the increase of frequency, while the wear rate firstly increases and then decreases slowly. Correspondingly, the wear mechanism changes from micro-machine wear to abrasive wear.