((中南大学 材料科学与工程学院，长沙 410083))
摘 要: 采用分子自组装的方法在Mg-Gd-Y-Zr合金表面制备双-(γ-三乙氧基硅丙基)四硫化物硅烷薄膜。通过傅立叶变换红外光谱研究薄膜结构特性，用扫描电镜观察薄膜表面形貌，并用电化学极化曲线和交流阻抗测试研究薄膜的耐蚀性能。结果表明，镁合金表面薄膜通过SiOSi链接形成网状结构，并可能通过形成SiOMg界面相结构与镁合金表面连接；晶界上薄膜厚度小于其他各处；薄膜将腐蚀电流密度降低2个数量级以上，明显提高了盐水浸泡过程中的阻抗值。
关键字: Mg-Gd-Y-Zr合金；硅烷；薄膜；腐蚀
（(School of Materials Science and Engineering, Central South University, Changsha 410083, China)）
Abstract:Bis-[triethoxysilylpropyl]tetrasulfide silane thin film was prepared, first by self-assembling the silane in solution of ethanol and deionized water and then aged at 120 ℃ for 60 min, on surface of Mg-Gd-Y-Zr magnesium alloy for improvement of its corrosion resistance. Fourier transform infrared spectroscopy (FTIR) was used for structural characterization of the formed silane film. Scanning electron microscope (SEM) was used for observing surface morphology of the film. Electrochemical potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used for evaluating the corrosion performances of the film. The results demonstrate that the film is cross linked through SiOSi, which is linked to surface of the Mg alloy through formation of interphases possibly as SiOMg. The film on the grain boundary of the magnesium alloy is thinner than those of other areas. The corrosion current density of silane treated Mg alloy is reduced by above two orders of magnitude than that of the bare alloy. The impedance values of silane treated Mg alloy, especially at the low frequency, are promoted by the silane film during the immersion in 3.5% NaCl solution till 24 h.
Key words: Mg-Gd-Y-Zr alloy; silane; film; corrosion
