Initial corrosion behaviors of AZ91 magnesium alloy in the presence of SO_2  

作　　者：CuiLin XiaogangLi 

机构地区：[1]CorrosionandProtectionCenter,KeyLaboratoryforCorrosion,ErosionandSurfaceTechnologyofBeijing,UniversityofScienceandTechnologyBeijing,Beijing100083,China [2]StateKeyLaboratoryforCorrosionandProtection,InstituteofMetalResearch,TheChineseAcademyofSciences,Shenyang110016,China

出　　处：《Journal of University of Science and Technology Beijing》2004年第5期433-441,共9页北京科技大学学报（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China (No. 50171011 );the 973 Science Foundation of China (No. 19990650).

摘　　要：The effects of SO_2 on the initial atmospheric corrosion of AZ91D magnesiumalloy were investigated in laboratory. Met-allographic observation, SEM (Scanning ElectronMicroscopy), XRD (X-ray Diffraction) and XPS (X-ray Proton Spectrograph) were used to analyze anddiscuss the initial surface morphology of corrosion layers and corrosion products. The corrosionrate of the alloy increases with increasing the content of SO_2. The initial attack has thecharacteristics of localized corrosion and preferentially concentrates on a phase. MgO and Mg(OH)_2form at first, which provide a protective layer, then the existence of SO_2 decreases the pH of thethin solution on the alloy, accelerates dissolution process, and promotes the formation of MgSO_3centre dot 6H_2O and MgSO_4 centre dot 6H_2O, meanwhile cracks were found on the corrosion productswith corrosion continuation. These soluble corrosion products and the cracks provide the paths forfiltering oxygen and corrosion pollutants into the matrix, which results in severe localizedcorrosion and the loss of protective function of film.The effects of SO_2 on the initial atmospheric corrosion of AZ91D magnesiumalloy were investigated in laboratory. Met-allographic observation, SEM (Scanning ElectronMicroscopy), XRD (X-ray Diffraction) and XPS (X-ray Proton Spectrograph) were used to analyze anddiscuss the initial surface morphology of corrosion layers and corrosion products. The corrosionrate of the alloy increases with increasing the content of SO_2. The initial attack has thecharacteristics of localized corrosion and preferentially concentrates on a phase. MgO and Mg(OH)_2form at first, which provide a protective layer, then the existence of SO_2 decreases the pH of thethin solution on the alloy, accelerates dissolution process, and promotes the formation of MgSO_3centre dot 6H_2O and MgSO_4 centre dot 6H_2O, meanwhile cracks were found on the corrosion productswith corrosion continuation. These soluble corrosion products and the cracks provide the paths forfiltering oxygen and corrosion pollutants into the matrix, which results in severe localizedcorrosion and the loss of protective function of film.

关 键 词：AZ91D magnesium alloy SO_2 initial stages atmospheric corrosion 

分 类 号：TG146.22[一般工业技术—材料科学与工程] X701[金属学及工艺—金属材料]