为探究转化液主盐酸根在成膜过程中的重要作用,采用扫描电子显微镜、能谱仪、x射线光电子谱仪结合电化学测试对两种常见酸根对应镨盐在镁合金表面形成转化膜后的形貌、成分、元素化学状态以及耐腐蚀性能进行比较,并基于酸根离子在水溶液中的反应过程分析其对转化膜成分及性能的作用机制.结果表明,以PrCl3作为主盐比以Pr(NO3)3作为主盐形成的化学转化膜更加致密；且前者受基体成分的影响较小,形成膜层的Pr、O含量(质量分数)明显高于后者；前者的耐腐蚀性能优于后者.酸根离子对转化膜成分及性能的影响主要体现在镨盐电离后在转化液中形成的相应稀酸与基体合金的作用机制及其对转化膜形成过程的影响.%To explore the important role of main salt acid radical during the film-forming process, the micro-morphology, composition elemental chemical states and corrosion resistance of two praseodymium - based chemical conversion coatings on magnesium alloys were observed by SEM, XPS, EDS and electrochemical test, respectively. Meanwhile, based on the reaction characteristics of main salt acid radical in aqueous solution, the film-forming mechanism was studied. The results show that the chemical conversion film prepared with PrCl3 as the main salt is more compact, less influenced by the substrate ingredient, and has better corrosion resistance than that of prepared with the main salt of Pr( NO3 )3. In addition, the concentration of both Pr and O element in the film formed in the PrCl3 solution is higher than that of formed in the Pr (NO3)3 solutions. The influence of the acid radical ion on the composition and property of praseodymium-based chemical conversion coating mainly manifests in the reaction between the corresponding dilute acids and the matrix alloy.
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