Degradation research of protective coating on AZ91D Mg alloy components via simulated contamination  

作　　者：Bao-sheng Liu Ya-fei Kuang Yue-sheng Chai Da-qing Fang Min-gang Zhang Ying-hui Wei 

机构地区：[1]College of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan,Shanxi 030024,China [2]Engineering Research Center for Magnesium Alloys of Shanxi Province,Taiyuan University of Science and Technology,Taiyuan,Shanxi 030024,China [3]College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China

出　　处：《Journal of Magnesium and Alloys》2016年第3期220-229,共10页镁合金学报（英文）

基　　金：the National Natural Science Foundation of China(grant no.51374151);the Natural Science Foundation of Shanxi Province(grant No.2015011038);the PhD Scientific Research Startup Foundation(grant no.20152011);Youth Scientific Research Foundation(grant no.20153003)of TYUST;the China Postdoctoral Science Foundation(grant no.20100471586)for funding provided in support of this work.

摘　　要：Accelerated environmental(hygrothermal)exposure experiments are performed on organic paints coated on commercial die-cast AZ91D Mg alloys to investigate the effects of contamination on blistering.Specifically,artificial human perspiration spray is used to contaminate the substrate surface.Blistering occurred only for paints that are spread on surfaces with the perspiration present.More blisters gradually form at longer test times,and the volume of blistering increases.Scanning electron microscopy indicates that blistering is initiated by contamination and/or substrate corrosion at the interface of the organic paints and the substrate.Blistering is characterized for two samples exposed to the hygrothermal environments for various times,and is found to be initially empty in the early stages.Hydrophilic chloride contaminants from the perspiration lead to in situ adhesion loss.Simultaneously,the paints volume expands,and the associated compressive stress causes it to bulge.After long-term test exposure,chloride anions corrode the substrate under the films,and MgO,Mg(OH)_(2),and Mg_(2)(OH)_(3)Cl corrosion products fill the blisters.Finally,a model of blistering evolution is discussed.

关 键 词：Mg alloys Organic paints Artificial human perspiration BLISTERING Corrosion 

分 类 号：TG1[金属学及工艺—金属学]