中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 11 November 2020 |
（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）
Abstract: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.
Key words: magnesium alloy; silane coating; layered double hydroxide; corrosion resistance
