镁锂合金表面磷酸盐转化膜研究  

Study on phosphate conversion coatings for Mg-Li alloy

作　　者：江溪[1] 张春红[1] 高丽丽 

机构地区：[1]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001

出　　处：《哈尔滨工程大学学报》2010年第3期391-394,共4页Journal of Harbin Engineering University

基　　金：国家自然科学基金资助项目(50603003)

摘　　要：针对镁锂合金耐腐蚀性差的问题,采用无铬磷酸盐转化技术在室温条件下在镁锂合金表面形成磷酸盐转化膜,以改善镁锂合金的耐腐蚀性.利用极化曲线、析氢实验、SEM、EDS对磷酸盐转化膜的耐腐蚀性和结构进行研究.结果表明,室温成膜的最佳时间是9 min;磷酸盐转化膜使镁锂合金的腐蚀电位正移,腐蚀电流降低,并显著降低了镁锂合金的析氢速度,提高了镁锂合金的耐腐蚀能力;磷酸盐转化膜由花形团簇组成,主要成分为Mg、O、P以及少量的C、Mn、K、Na、Al.硬度与结合力分析表明,磷酸盐转化膜硬度明显高于镁锂合金,并与镁锂合金基体结合力良好,能够起到保护镁锂合金的作用.In order to improve the corrosion resistance of Mg-Li alloys, a room temperature chromium-free phosphate surface conversion technique for Mg-Li alloys was investigated. The corrosion resistance and structure of the phosphate conversion coating were characterized by investigating its polarization curves and evolved hydrogen using scanning electron microcopy （SEM） and energy dispersive spectrometer （EDS）. The results indicated that the optimum conversion time was 9 min and the phosphate conversion coating increased the corrosion potential, reduced the corrosion current and the hydrogen evolution rate of the Mg-Li alloy, improving its corrosion resistance. The phosphate conversion coating, which formed flower-shaped clusters covering the Mg-Li alloy surface, was composed of Mg, O, P and a small amount of C, Mn, K, and Na. Analysis of the hardness and adhesion properties showed that the hardness of the phosphate conversion coating was obviously higher than that of an untreated Mg-Li alloy, and the adhesion property between phosphate conversion coating and Mg-Li alloy was excellent. Therefore, the phosphate conversion coating could provide good protection for a Mg-Li alloy.

关 键 词：镁锂合金 化学转化 磷酸盐 耐蚀性 膜结构 

分 类 号：TG178[金属学及工艺—金属表面处理]