(西安理工大学 材料科学与工程学院，西安 710048)
摘 要: 在硅酸钠电解液中利用交流脉冲微弧氧化电源对LY12铝合金进行表面处理，研究微弧氧化初期成膜和后期生长膜层的微观结构差异，探讨铝合金微弧氧化陶瓷层的形成与生长机制。结果表明：初期成膜过程中发生电化学沉积反应，形成电解液中溶质元素的氧化物，增大铝合金表面的阻抗值；后期生长过程中，基体铝与OH−放电所产生的活性氧发生化合反应，形成Al2O3陶瓷层，溶质元素消耗极少；铝合金样品表面获取的预制备膜重新参与陶瓷层的生长，可明显缩短微弧氧化起弧时间、降低起弧电压，同时提升击穿电压的稳定值。
关键字: 铝合金；微弧氧化；陶瓷层；生长机制；预制备膜
microarc oxidation coating on LY12 aluminium alloy
（School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China）
Abstract:LY12 aluminium alloy was surface treated by microarc oxidation in the Na2SiO3 solution using AC pulse electrical source. The microstructure difference of the coatings formed at different stages of microarc oxidation was researched, and the growth mechanism of ceramic coating on aluminium alloy was discussed. The results show that electrochemical deposition reaction happens during forming incipient coating, and the oxide containing the element of the electrolyte forms. So, this oxide coating increases the impedance value of aluminium alloy. The combination of Al from the substrate and active O generated by the discharge of OH− ion forms Al2O3 coating, and in this process, the element of the electrolyte is consumed little. Since the prefab coating is participated in the process of forming ceramic coating, the prefab coating is prepared on the aluminum alloy surface, it is helpful to shortening arc starting time, reducing the voltage and increasing the steady value of broken down voltage.
Key words: aluminium alloy; microarc oxidation; ceramic coating; growth mechanism; prefab coating
