Microstructure and electrochemical behavior of cerium conversion coating modified with silane agent on magnesium substrates
Microstructure and electrochemical behavior of cerium conversion coating modified with silane agent on magnesium substrates
复制标题
镁基体硅烷改性铈转化膜的微观结构和电化学行为
DOI：
10.1016/j.apsusc.2016.03.150
复制
发表时间：
2016-07-15
影响因子：
6.7
通讯作者：
Xu, Haigang
中科院分区：
文献类型：
--
作者：
Lei, Li;Shi, Jing;Xu, Haigang
采用不同浓度的硅烷试剂双-（γ-三乙氧基硅丙基）-四硫化物（BTESPT）对镁合金表面进行改性，得到了铈转化膜。涂层的详细性能和BTESPT作为添加剂的作用进行了研究，并进行了仔细的讨论。采用扫描电镜（SEM）、水接触角、X射线光电子能谱（XPS）、动电位扫描和电化学阻抗谱（EIS）等方法对涂层的形貌、润湿性、化学成分和耐蚀性进行了表征。用交流阻抗谱研究了涂层的电化学行为。结果表明，通过改变硅烷浓度可以控制涂层的形貌和成分。铈离子与硅烷分子的结合能促进涂层的形成，使涂层更均匀，疏水性更强。由于Si-O-Si和Si-O-M化学键的形成，涂层变得更加致密，涂层与镁基体的结合强度大大提高。在25 ml L ~（-1）BTESPT改性条件下，涂层在腐蚀介质中的耐蚀性最佳。研究表明，硅烷改性的铈转化膜在应用于耐腐蚀性方面值得谨慎。(C)© 2016 Elsevier B. V.版权所有。
The cerium conversion coating with and without different concentrations of silane agent bis-(gamma-triethoxysilylpropyl)-tetrasulfide (BTESPT) modification is obtained on magnesium alloys. Detailed properties of the coatings and the role of BTESPT as an additive are studied and followed with careful discussion. The coating morphology, wettability, chemical composition and corrosion resistance are characterized by scanning electronic microscope (SEM), water contact-angle, X-ray photoelectron spectroscopy (XPS), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of the coatings is investigated using EIS. The results indicate that the coating morphology and composition can be controlled by changing silane concentration. The combination of cerium ions and silane molecules could promote the formation of more homogenous and higher hydrophobic coating. The coating turns to be more compact and the adhesive strength between the coating and the magnesium substrate are strongly improved with the formation of Si-O-Si and Si-O-M chemical bonds. The optimum corrosion resistance of the coating in the corrosive media is obtained by 25 ml L-1 BTESPT modification. This whole study implies that the cerium conversion coating modified with certain silane agent deserves cautiousness before its application for corrosion resistance. (C) 2016 Elsevier B.V. All rights reserved.