电解质及其交互作用对A356铝合金微弧氧化膜耐蚀性的影响  

Effect of electrolytes and their interaction on corrosion resistance of micro-arc oxidation coating of A356 Al alloy

作　　者：王占营[1] 马颖[1] 梁志龙 安凌云 WANG Zhan-ying;MA Ying;LIANG Zhi-long;AN Ling-yun(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050

出　　处：《中国有色金属学报》2023年第2期549-564,共16页The Chinese Journal of Nonferrous Metals

基　　金：甘肃省创新研究群体计划资助(1111RJDA011);有色金属先进加工与再利用国家重点实验室开放基金资助项目(SKLAB02015006)。

摘　　要：采用回归正交旋转组合试验设计,建立A356铝合金微弧氧化膜点滴及电化学耐蚀性关于Na_(2)SiO_(3)、NaOH及KF浓度的回归方程,通过方差分析(ANOVA)对回归模型的显著性进行检验,结合响应面图进一步分析电解质对膜层微观形貌、物相组成及耐蚀性的影响。结果表明:所建立的回归模型显著,失拟不显著,且回归模型的拟合度及预测精度都比较高。帕累托分析显示,主盐Na_(2)SiO_(3)对膜层点滴、电化学耐蚀性的影响都比较大,NaOH的影响次之,且NaOH与Na_(2)SiO_(3)之间存在明显的交互作用。响应面分析显示,高浓度的Na_(2)SiO_(3)搭配低浓度的NaOH才有利于涂层耐蚀性的提高。通过Pearson相关分析可知,膜层的点滴耐蚀性主要受膜层厚度的影响,而电化学耐蚀性主要依赖膜层的致密度及孔隙率。膜层点滴、电化学耐蚀性的腐蚀机制不同是导致电解质对两指标影响有所不同的主要原因。The regression equations of Na_(2)SiO_(3),NaOH and KF for spotting and electrochemical corrosion resistance of micro-arc oxidation coatings on A356 aluminum alloy were established by the regression orthogonal rotating combined experimental design.The significance of the regression model was tested by analysis of variance(ANOVA).The effect of electrolytes on the corrosion resistance of the coating were further analyzed by the response surface methodology(RSM),microstructure observation and phase compositions analysis.The results show that the obtained regression models are very significant and have prediction accuracy,and the lack of fit is not significant.Pareto analysis shows that the main salt Na_(2)SiO_(3)has a great influence on the coating corrosion resistance,followed by NaOH,and there is an obvious interaction between NaOH and Na_(2)SiO_(3).RSM shows that high concentration of Na_(2)SiO_(3)combined with low concentration of NaOH is beneficial to the improvement of the the coating corrosion resistance.According to Pearson correlation analysis,the spotting corrosion resistance primarily depends on the coating thickness(r=0.78453),and the electrochemical corrosion resistance is greatly affected by the coating density and porosity(r=0.89748).The different corrosion mechanisms of spotting and electrochemical corrosion resistance of the coating are the main reason for different effects of electrolytes on the two indicators.

关 键 词：A356铝合金 微弧氧化 电解液 回归建模 响应面法 

分 类 号：TG174.4[金属学及工艺—金属表面处理]