Effect of scratch on corrosion resistance of calcium phosphate conversion coated AZ80 magnesium alloy  

划痕对AZ80镁合金上磷酸钙转化涂层耐腐蚀性能的影响

作　　者：Xue-jiao JIA Jiang-feng SONG Xiao-rong QU Fu-yong CAO Bin JIANG Andrej ATRENS Fu-sheng PAN 贾雪娇;宋江凤;屈小荣;曹福勇;蒋斌;Andrej ATRENS;潘复生(重庆大学,机械传动国家重点实验室,重庆400044;重庆大学国家镁合金材料工程技术研究中心,重庆400044;青海盐湖工业股份有限公司,青海816000;厦门大学材料学院海洋材料腐蚀防护研究中心,厦门361005;School of Mechanical and Mining Engineering,The University of Queensland,Brisbane Qld 4072,Australia)

机构地区：[1]State Key Laboratory of Mechanical Transmissions,Chongqing University,Chongqing 400044,China [2]National Engineering Research Center for Magnesium Alloy,Chongqing University,Chongqing 400044,China [3]Qinghai Salt Lake Industry Co.,Ltd.,Qinghai 816000,China [4]Center for Marine Materials Corrosion and Protection,College of Materials,Xiamen University,Xiamen 361005,China [5]School of Mechanical and Mining Engineering,The University of Queensland,Brisbane Qld 4072,Australia

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第1期147-161,共15页中国有色金属学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.52071036,51701027);the Fundamental Research Funds for the Central Universities,China(Nos.2020CDJQY-A002,2021CDJCGJ009);the National Key Research and Development Program of China(Nos.2016YFB0301100,2016YFB0101700)。

摘　　要：In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and hydrogen evolution experiment were performed to study the corrosion resistance of AZ80,AZ80 with CPCC and coated AZ80 with scratch.The results show that the coating improves the corrosion resistance of the AZ80 from a current density of(85±4)to(4±1)μA/cm^(2).When the coating was damaged,its protection on substrate would be reduced.The scratch with a length of around 12 mm on the coating reduced the corrosion resistance to a current density of(39±1)μA/cm^(2).In addition,the corrosion occurred initially in the scratch area and the corrosion site first occurred at the junction of the scratch and the coating.Besides,the micro corrosion mechanism of the specimen containing scratch was clarified.通过电化学测试、扫描振动电极技术、浸泡实验和析氢实验分析AZ80合金、磷酸钙转化涂层以及含划痕涂层的耐腐蚀性能,进而研究划痕对AZ80镁合金上磷酸钙转化膜腐蚀行为的影响。结果表明,AZ80合金经涂层处理后腐蚀性能提高,其腐蚀电流密度由(85±4)μA/cm^(2)降低为(4±1)μA/cm^(2)。当涂层被破坏后,其对基体的保护能力下降。涂层上一条长约12 mm的划痕可使其腐蚀电流密度增加到(39±1)μA/cm^(2)。此外,样品上的划痕区域最先开始腐蚀,进一步观察发现,腐蚀发生于划痕与涂层的交界处。由此,提出含划痕涂层的显微腐蚀机理。

关 键 词：magnesium alloy AZ80 alloy SCRATCH conversion coating corrosion resistance scanning vibrating electrode technique(SVET) 

分 类 号：TG174.4[金属学及工艺—金属表面处理]