Process Optimization for Cerium Oxide Based Conversion Coating of AZ91D Magnesium Alloy at Room Temperature  

作　　者：Chen Dongchu Wu Jianfeng Ye Shulin 

机构地区：[1]Foshan Univ, Sch Sci, Foshan 528000, Peoples R China

出　　处：《稀有金属材料与工程》2012年第S1期243-246,共4页Rare Metal Materials and Engineering

基　　金：Natural Science Foundation of Guangdong Province,China(7010404);Project of Science&Technology of Guangdong Province(2008B030302011)

摘　　要：The Ce2SO4/H2O2 containing solution is used to prepare a chrome-free cerium oxide based chemical conversion coating on AZ91D magnesium alloy at room temperature,and an orthogonal experiment was carried out to optimize the treating process.The effect of preparing parameters on the coating growth and the corrosion resistance were studied.It was found that H2O2 is the dominant influence factor on the coating weight gain in the orthogonal experiment,with Ce(SO4)2 coming next and immersion time having the least impact,while the most dominant influence factor on the corrosion resistance is Ce(SO4)2,with H2O2 coming next and immersion time having the least impact.The coating has the best corrosion resistance,treated in the solution of 10 g/l Ce(SO4)2 and 12 ml/l H2O2 for 4 min.SEM was adopted to study the micro-morphology of the conversion coating on magnesium alloy surface The prolonged immersion time duration or the increased concentration of Ce(SO4)2 and H2O2 will increase the coating thickness,but tiny cracks appears resulted from the fast coating deposition.The Ce2SO4/H2O2 containing solution is used to prepare a chrome-free cerium oxide based chemical conversion coating on AZ91D magnesium alloy at room temperature,and an orthogonal experiment was carried out to optimize the treating process.The effect of preparing parameters on the coating growth and the corrosion resistance were studied.It was found that H2O2 is the dominant influence factor on the coating weight gain in the orthogonal experiment,with Ce(SO4)2 coming next and immersion time having the least impact,while the most dominant influence factor on the corrosion resistance is Ce(SO4)2,with H2O2 coming next and immersion time having the least impact.The coating has the best corrosion resistance,treated in the solution of 10 g/l Ce(SO4)2 and 12 ml/l H2O2 for 4 min.SEM was adopted to study the micro-morphology of the conversion coating on magnesium alloy surface The prolonged immersion time duration or the increased concentration of Ce(SO4)2 and H2O2 will increase the coating thickness,but tiny cracks appears resulted from the fast coating deposition.

关 键 词：MAGNESIUM alloy CERIUM CONVERSION coating CHROME-FREE ROOM temperature 

分 类 号：TG146.4[一般工业技术—材料科学与工程]