6063铝合金微弧氧化陶瓷涂层的显微组织和力学性能

摘要

以硅酸盐、硼酸盐和铝酸盐为主要溶液，分别在这3种溶液中添加纳米添加剂Al2O3和TiO2以及不添加纳米添加剂，制备6063铝合金的微弧氧化陶瓷涂层。利用扫描电镜(SEM)、电子能谱分析(EDS)、X射线衍射、硬度和摩擦磨损测试研究这些涂层的显微组织和力学性能。SEM结果显示，含纳米添加剂涂层的孔洞比不含添加剂涂层的孔洞少。X射线衍射结果表明，在每种溶液中含添加剂的涂层比不含添加剂的涂层含有更多的氧化物成分，这与EDS的分析结果是一致的。力学性能测试结果表明，含纳米添加剂Al2O3的涂层较其他各种情况下在硅酸盐、硼酸盐和铝酸盐中制备出的涂层具有更高的硬度；纳米添加剂在这3种溶液中都能够提高微弧氧化涂层的耐磨性能。此外，无论是否含有纳米添加剂，硼酸盐微弧氧化涂层相对于硅酸盐和铝酸盐涂层都表现出较差的耐磨性能。%The microstructure and mechanical properties of ceramic coatings formed on 6063 aluminium alloy obtained in silicate-, borate-and aluminate-based electrolyte without and with nanoadditive Al2O3 and TiO2 by micro-arc oxidation (MAO) were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), microhardness and friction−abrasion tests, respectively. SEM results show that coatings with nanoadditive have less porosities than those without nanoadditive. XRD results reveal that nanoadditive-containing coatings contain more oxides compared with nanoadditive-free coatings in all cases, which are consistent with the EDS analysis. Mechanical properties tests show that nanoadditive Al2O3-containing coatings have higher microhardness values compared with the other coatings obtained in silicate-, borate- and aluminate-based electrolyte. On the other hand, nanoadditive has a positive effect on improving the wearing-resistance of MAO coatings in all cases. Furthermore, the borate-MAO coatings present an inferior anti-wearing property compared with the silicate-and aluminate-MAO coatings for both the nanoadditive-free and nanoadditive-containing coatings.