镁合金表面铈盐掺杂硅烷膜的腐蚀电化学行为  

Electrochemical Corrosion Behavior of Cerium Salt Doped Silane Composite Films on AZ91D Magnesium Alloy

作　　者：吴海江[1] 杨飞英 邹利华[1] 王小明[1] 曾娣平[1] 郭文敏[1] 

机构地区：[1]邵阳学院机械与能源工程系,湖南邵阳422000

出　　处：《表面技术》2017年第9期209-214,共6页Surface Technology

基　　金：湖南省自然科学基金资助项目(2015JJ2064);湖南省教育厅资助科研项目(15B213);邵阳市科技计划项目(2016FJ07)~~

摘　　要：目的为进一步提升镁合金表面常规硅烷膜的耐蚀性能。方法在γ-氨丙基三乙氧基硅烷溶液中掺杂0.50 g/L硝酸铈,采用简单化学浸渍处理,在AZ91D镁合金基体表面制备了铈盐掺杂硅烷膜。借助扫描电子显微镜(SEM)观察了铈盐掺杂前后硅烷膜的表面微观形貌,通过开路电位-时间曲线、电化学交流阻抗谱(EIS)和中性盐雾试验(NSS)研究了铈盐掺杂对5%Na Cl溶液中硅烷膜耐蚀性能的影响。结果铈盐掺杂硅烷膜比普通硅烷膜更厚且平整,其致密性、均匀一致性较好,完全覆盖了镁合金基体,已看不到磨痕。铈盐掺杂硅烷膜的稳定电位约为-1.31 V,且需要的稳定时间最长。铈盐掺杂硅烷膜具有更大的低频阻抗数值,有效遏制了侵蚀性粒子向镁合金基体的迁移和扩散,避免了镁合金基体发生阳极溶解反应。结论采用向硅烷溶液中添加硝酸铈的方法,能够在AZ91D镁合金表面制备出铈盐掺杂硅烷膜。由于铈离子在某种程度上修复了硅烷膜层中的微裂纹和缺陷,显著提升了硅烷膜的耐蚀能力。The work aims to further improve corrosion resistance of conventional silane films on AZ91D magnesium alloy. The 吴海江-aminopropyltriethoxysilane solution were doped with 0.50 g/L cerium nitrate to prepare cerium salt-doped silane films on AZ91D magnesium alloy by simple chemical immersion treatment. Surface morphology of the silane films before and after be- ing doped with cerium salt was observed with scanning electron microscopy （SEM）. Effects of cerium salt doping on corrosion resistance of the silane films in 5% NaCI solution were studied based upon open circuit potential-time curves, electrochemical impedance spectroscopy （EIS） and neutral salt spray test. Cerium salt-doped silane films were more smooth and uniform, thicker and denser than that of the conventional silane films. The magnesium alloy substrate was completely covered and no polishing scratch was seen. Stable potential of the cerium salt-doped silane films was about -1.31 V, and it needed longer stabilization time. The cerium salt-doped silane films produced a larger low-frequency impedance value, thus effectively inhibiting the mi- gration and diffusion of erosive particles toward the magnesium alloy substrate, and avoiding anodie dissolution of magnesium alloy substrate. By adding eerium nitrate to silane solution, the cerium salt-doped silane films could be prepared on AZ91D magnesium alloy. Corrosion resistance of the silane films was improved significantly because micro cracks and defects on the silane films were repaired to some extent by cerium ions.

关 键 词：铈盐 Γ-氨丙基三乙氧基硅烷 AZ91D镁合金 开路电位.时间曲线 电化学阻抗谱 耐蚀性 

分 类 号：TG174.45[金属学及工艺—金属表面处理]