铝合金微弧氧化复合工艺制备陶瓷膜的油摩擦特性

Research on Wear-resistance under Oil Lubrication of Ceramic Coating on Aluminum Alloy Prepared by Micro-arc Oxidation Composite Process

为改善7075铝合金微弧氧化陶瓷膜性能,利用恒流-恒压复合工艺制备微弧氧化陶瓷膜。采用涂层厚度仪、显微硬度计测量陶瓷膜厚度、显微硬度;采用扫描电镜(SEM)和X射线衍射仪(XRD)分析陶瓷膜的表面形貌、磨痕形貌和相组成;采用摩擦磨损试验机研究陶瓷膜油摩擦特性。结果表明:在氧化时间为75 min(恒流)-30 min(恒压)时,陶瓷膜平均厚度达到81μm,陶瓷膜致密层硬度达到1648 HV;陶瓷膜主要由α-Al_2O_3和γ-Al_2O_3组成;微弧氧化陶瓷膜微孔结构有利于改善油润滑条件下的耐磨性;在油润滑条件下,摩擦系数和磨损量随着转速的增大而变大。

In order to improve the properties of ceramic coating on 7075 aluminum alloy by micro-arc oxidation （MAO）, the method of constant current mode combining with constant voltage mode was used to prepare the ceramic coating. The thickness and hardness of the coating were measured by coating thickness meter and micro Vickers hardness measurer. The surface morphologies ,wear scar morphology and phase composition were analyzed by scanning electron microscope （SEM） and X-ray diffraction （XRD）. The wear resistance under oil lubrication was studied by friction and wear tester. The results show that the average thickness and hardness reach 81μm and 1648 HV, respectively, when the oxidation time is 75 min for constant current mode and the oxidation time is 30 min for constant voltage mode. The ceramic coating primarily consists of α-Al2O3 and γ-Al2O3. The micro-cavities in the ceramic coating are able to improve the wear resistance under oil lubricating. Under oil lubrication, the friction coefficient and wear mass loss increase with the rotational velocity increasing.