Corrosion resistance of Mg−Al LDH/Mg(OH)2/silane−Ce hybrid coating on magnesium alloy AZ31  

AZ31镁合金上Mg−Al LDH/Mg(OH)2/硅烷−Ce杂化涂层的耐蚀性

作　　者：Zai-meng QIU Rong-chang ZENG Fen ZHANG Liang SONG Shuo-qi LI 仇在孟;曾荣昌;张芬;宋亮;李硕琦(山东科技大学材料科学与工程学院轻金属腐蚀实验室,青岛266590;郑州大学材料科学与工程学院,郑州450002)

机构地区：[1]Corrosion Laboratory for Light Metals,College of Materials Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China [2]School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450002,China

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第11期2967-2979,共13页中国有色金属学报（英文版）

基　　金：Projects(51601108,21676285,51571134)supported by the National Natural Science Foundation of China;Project(2017RCJJ015)supported by Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents,China;Project(2014TDJH104)supported by the Shandong University of Science and Technology Research Fund,China。

摘　　要：An environmentally-friendly hybrid coating on AZ31 magnesium alloy substrates was reported.The synergic effect was studied on Mg−Al-layered double hydroxide Mg−Al LDH/Mg(OH)2-coated AZ31 magnesium alloy via an in-situ steam coating process and a subsequent combined surface modification of bis-[triethoxysilylpropyl]tetrasulfide(BTESPT)silane and Ce(NO3)3.The microstructure and composition characteristics of the hybrid coatings were investigated by means of X-ray diffraction(XRD),scanning electronic microscopy(SEM),Fourier transform infrared spectrophotometry(FT-IR)and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the coated samples was evaluated by potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution rate during immersion in 3.5 wt.%NaCl solution.The results show an improved corrosion resistance of the alloy in the presence of BTESPT silane and Ce(NO3)3.This is most likely due to the synergistic effect of steam coating and silane coating to enhance the barrier properties of hybrid coating.In addition,the formation mechanism and anti-corrosion mechanism of coatings were discussed.在AZ31镁合金基体上涂覆一种环保杂化涂层。通过原位蒸汽涂覆工艺制备Mg−Al层状双氢氧化物Mg−Al LDH/Mg(OH)2涂层,随后使用双-[三乙氧基甲硅烷基丙基]四硫化物(BTESPT)硅烷和Ce(NO3)3对蒸汽涂层进行表面改性,研究两者对AZ31镁合金的协同作用。通过X射线衍射仪(XRD)、扫描电子显微术(SEM)、傅里叶变换红外光谱(FT-IR)和X射线光电子能谱(XPS)研究杂化涂层的显微结构和组成特征。通过电位动力学极化(PDP)、电化学阻抗谱(EIS)和浸入3.5 wt.%NaCl溶液中的析氢速率评价涂层样品的耐蚀性。结果表明,在BTESPT硅烷和Ce(NO3)3存在下,合金的耐蚀性得到改善,这很可能是由于蒸汽涂层和硅烷涂层的协同作用增强了杂化涂层的阻隔性能。此外,还讨论涂层的形成机理和耐蚀机理。

关 键 词：magnesium alloy silane coating layered double hydroxide corrosion resistance 

分 类 号：TG174.4[金属学及工艺—金属表面处理]