摘要
Ceramic coating was prepared on cast Al-Cu-Li alloy by micro-arc oxidation(MAO) in a silicate electrolyte solution with additives including Na2WO4 and Na OH. The effect of NaOH addition varying from 1 to 9 g/L on the microstructure and corrosion behavior of the coatings was investigated. The coating was characterized by XRD, XPS and SEM with respect to the composition and microstructures. The results show that NaOH promoted the formation of oxides in the reaction of MAO and contributed to the increase of layer thickness. Electrochemical tests(polarization curve and EIS) and mass loss test indicate that the corrosion resistance of the coated Al-Cu-Li alloy was improved with the increased addition of NaOH. Moreover, the results prove that the alumina coating formed in the electrolyte with 7 g/L NaOH showed the best corrosion resistance. The examination of the full immersion corrosion test presents the same result of corrosion resistance.
采用含有Na2WO4和不同NaOH浓度的硅酸盐系列电解液,利用微弧氧化(MAO)技术在Al-Cu-Li合金表面制备陶瓷涂层,研究NaOH浓度在1-9 g/L范围内对涂层显微组织和腐蚀行为的影响。利用X射线衍射(XRD)、X射线光电子能谱(XPS)和扫描电子显微镜(SEM)对膜层的组成和微观结构进行表征。结果表明,NaOH促进MAO反应中氧化物的生成,使膜层厚度增加。电化学腐蚀测试(极化曲线、交流阻抗谱)和质量损失试验确定膜层的耐蚀性随NaOH加入量的增加而提高,且在7g/LNaOH溶液中制备的膜层耐蚀性最优。全浸泡腐蚀试验也给出一致的结果。
基金
supported by the National Natural Science Foundation of China (51871148,51821001)
the United Fund of National Department of Education and Equipment Development (6141A02033245)
the National Key R&D Program of China (2016YFB0301003)。
