铈盐掺杂GPTMS/TEOS硅烷杂化膜腐蚀电化学行为随时间的变化  

Changes of Corrosion Electrochemical Behavior of Cerium Nitrate Doped GPTMS/TEOS Silane Hybrid Films with Immersion Time

作　　者：张金涛[1] 李春东[1] 潘亮[1] 胡吉明[2] 

机构地区：[1]常州工学院化工系,常州213022 [2]浙江大学化学系,杭州310027

出　　处：《腐蚀与防护》2009年第12期879-882,908,共5页Corrosion & Protection

基　　金：国家自然科学基金项目(50871101);江苏省高校自然科学研究指导性项目(YW06005)资助

摘　　要：以γ-环氧丙氧丙基三甲氧基硅烷(GPTMS)和正硅酸乙酯(TEOS)为前躯体,采用溶胶-凝胶法在LY12铝合金基体表面制备了铈盐Ce(NO3)3掺杂有机-无机杂化膜。通过极化曲线与电化学阻抗谱(EIS)研究铈盐掺杂硅烷杂化膜在3.5%(质量分数)NaCl溶液中耐蚀性能随浸泡时间的变化。结果表明,硅烷杂化膜的极化阻抗值随浸泡时间延长而缓慢降低,但浸泡183 h后仍显著高于金属基体;铝合金点蚀电位在浸泡期间呈现先降低后升高再降低的变化。在浸泡初期,EIS曲线的高频容抗行为显著。从69 h至260 h浸泡试验结束,低频阻抗值保持基本稳定。上述变化与膜中掺杂的铈盐具有自修复性质密切相关。Silane-based organic-inorganic hybrid films doped with cerium nitrate were prepared on LY12 aluminum alloy by sol-gel method using γ-glycidoxypropyltrimethoxysilane （γ-GPTMS） and tetraethylorthosilieate （TEOS） as precursors. The evolution of corrosion resistance of the Ce-doped silane-based hybrid coating with immersion time in 3.5% NaCl solution was investigated by polarization curve and electrochemical impedance spectroscopy （EIS） measurements. The results indicated that the polarization resistance values of the Ce-doped silane-based hybrid films decreased slowly with the increase of immersion time, and was still distinctly greater than that of aluminum substrate after 183 h of immersion. The pitting potentials of the Al alloy presented a variation of decreasing, then increasing and finally decreasing during immersion in NaCl solution. In the first period of immersion, the obvious capacitive behavior in high frequency range of EIS could be observed. The low frequency impedance values remained approximately constant in immersion from 69 h to the end of the experiment. The above changes were related to the self-healing ability of cerium salt doped in the silane hybrid films.

关 键 词：铈盐 有机硅烷 铝合金 极化曲线 电化学阻抗谱 

分 类 号：TG174.36[金属学及工艺—金属表面处理]