Effect of applied potential on the microstructure, composition and corrosion resistance evolution of fluoride conversion film on AZ31 magnesium alloy

作     者：Liping Wu Changgang Wang Durga Bhakta Pokharel Ini-Ibehe Nabuk Etim Lin Zhao Junhua Dong Wei Ke Nan Chen 无

作者机构：Environmental Corrosion CenterInstitute of Metal ResearchChinese Academy of Sciences 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2018年第34卷第11期

页      面：2084-2090页

核心收录：

学科分类：080503[工学-材料加工工程] 0806[工学-冶金工程] 0817[工学-化学工程与技术] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0702[理学-物理学] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported financially by the National Natural Science Foundation of China (No. 51701221) 

主　　题：Potentiostatic Fluoride conversion film AZ33 magnesium alloy KF solution Corrosion 

摘      要：AZ31 magnesium（Mg） alloy was potentiostatic polarized in 0.1 M deaerated KF solution with pH 7.5 from-0.4 V to-1.4 V with an interval of-0.2 V. The polarization process was described by the potentiostatic current decay. The resultant film was analyzed by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS） and electrochemical impedance spectroscopy（EIS）. The results demonstrated that the deposited film included a Mg（OH）2/MgF2 containing inner layer and a Mg（OH）-2/MgF2/KMgF3 comprising outer layer. The high polarized potential produced high content of MgF2 but low content of KMgF3 and thin film. Conversely, the low polarized potential produced small content of MgF2 but high content of KMgF3 and thick film. The optimal corrosion resistance of the deposited film was obtained at-1.4 V, which was closely related with the content of MgF2 and KMgF3 and the film thickness.