AZ91镁合金磷酸盐-高锰酸盐转化膜工艺的研究  

Conversion Film Technique of Permanganate-Phosphate Solution on AZ91 Magnesium Alloy

作　　者：农登[1] 宋东福[1] 戚文军[1] 梁涛 王海艳[1] 

机构地区：[1]广州有色金属研究院,广东广州510650 [2]广州市机械科学研究院有限公司,广东广州510700

出　　处：《稀有金属材料与工程》2013年第5期1062-1066,共5页Rare Metal Materials and Engineering

基　　金：广东省粤港关键领域重点突破项目(2010A090604001);广东省中国科学院全面战略合作项目(2010A090100033)

摘　　要：采用正交试验法设计了以磷酸盐-高锰酸盐为基础的无铬转化工艺优化试验,讨论了工艺对转化膜厚度、耐蚀性能及形貌的影响。结果表明:当ZnSO4和NaF的浓度分别为5和1g/L,pH值为4时,转化膜耐蚀性能可提高8倍以上。转化液pH值对膜层厚度、形貌及耐蚀性能均影响显著,当pH过小时,膜层疏松易脱落,仅剩下内层转化膜,膜层较薄,耐蚀性能较差;当pH为4时,膜层厚度达到极大值,内、表膜层结合紧密,大幅改善转化膜的耐蚀性能;当pH值继续增大时,膜层致密,但内、外膜层结合力较差,耐蚀性能有小幅提高。The process parameters of a chromium-free conversion technique based on permanganate-phosphate solution on die cast magnesium alloy AZ91 have been optimized by orthogonal experiments. The effects of process parameters on thickness, corrosion resistance and morphology of the conversion film were discussed. The results show that the corrosion resistance of the conversion film can be improved by more than 8 times compared with that of the substrate when the concentration of ZnSO4 and NaF are 5 and 1g /L, respectively, and pH=4. Furthermore, the pH value has significantly affected the thickness, morphology and corrosion resistance of the film. The film is loose and easy to fall off when the pH is too low. Meanwhile only the thin inner conversion film remains and the corrosion resistance is poor. When pH=4, the film thickness reaches its maximum value, and the inner film adheres closely to the outer film, which significantly improve the corrosion resistance of the conversion coating. However, when the pH increases further, the film becomes dense, but the corrosion resistance increases slightly because of poor bonding between the inner film and the outer one.

关 键 词：镁合金 磷酸盐-高锰酸盐 转化膜 耐蚀性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]