Evaluation of electrochemical impedance and biocorrosion characteristics of as-cast and T4 heat treated AZ91 Mg-alloys in Ringer’s solution  

作　　者：Nagaraj M.Chelliah Pambannan Padaikathan Ram Kumar 

机构地区：[1]Department of Metallurgical Engineering,PSG College of Technology,Coimbatore 641004,Tamil Nadu,India [2]Department of Materials Engineering,Indian Institute of Science,Bangalore 560012,Karnataka,India [3]Department of Mechanical Engineering,Indian Institute of Technology,Rupnagar 140001,Punjab,India

出　　处：《Journal of Magnesium and Alloys》2019年第1期134-143,共10页镁合金学报（英文）

摘　　要：The present study aims at understanding the electrochemical impedance and biocorrosion characteristics of AZ91 Mg-alloy in Ringer’s solution.As-cast AZ91 Mg-alloy was subjected to T4 heat treatment in a way to homogenize its microstructure by dissolving most of theβ-Mg 17 Al 12 phase at the vicinity of grain boundaries.The electrochemical impedance and biocorrosion performances of these two different microstructures(as-cast and T4 heat treated AZ91 Mg-alloys)in Ringer solution were evaluated by electrochemical impendence spectroscopy,potentiodynamic polarization and weight loss method.EIS spectra showed that both microstructures exhibit similar dynamic response as a function of the immersion time;however,the value of impedance and maximum phase angle are about 50%higher in as-cast AZ91 Mg-alloy as compared to that of homogenized AZ91 Mg-alloy.Weight loss measurement indicated that corrosion resistance of as-cast AZ91 was significantly better than that of homogenized AZ91.Microstructural and XRD analysis revealed that as-cast AZ91 contains a passive film of MgCO_(3)and CaCO_(3)precipitates with near spherical morphologies,whereas homogenized AZ91 comprised mainly unstable Mg(OH)_(2)film featured by irregular plate-like morphologies.

关 键 词：Mg-alloys Ringers solution HOMOGENIZATION Corrosion Electrochemical impedance Spectroscopy(EIS) Weight loss 

分 类 号：TG1[金属学及工艺—金属学]