2A12铝合金表面铈盐掺杂硅烷杂化膜在3.5%NaCl溶液中耐蚀性能的电化学研究

ELECTROCHEMICAL STUDY OF CORROSION RESISTANCE OF CERIUM NITRATE DOPED SILANE-BASED HYBRID FILMS ON ALUMINUM ALLOY 2A12

采用溶胶-凝胶法,以γ-环氧丙氧丙基三甲氧基硅烷(γ-GPTMS)和正硅酸乙酯(TEOS)为前驱体,在2A12铝合金表面制备了稀土铈盐(Ce(NO_3)_3)掺杂的有机-无机杂化膜,研究了铈盐掺杂浓度和涂层固化温度等工艺条件.通过极化曲线和电化学阻抗谱(EIS),比较了掺杂与未掺杂有机-无机硅烷杂化膜、铬酸盐转化膜和RE转化膜在3.5%NaCl(质量分数)溶液中的耐腐蚀性能.测试结果均表明,铈盐掺杂硅烷杂化膜的极化电阻比掺杂前增大了约13倍,并显著高于铬酸盐转化膜和RE转化膜.

Silane-based organic-inorganic hybrid films doped with cerium nitrate were prepared on 2A12 aluminum alloys by sol-gel method usingγ-glycidoxypropyltrimethoxysilane（γ-GPTMS）and tetraethylorthosilicate（TEOS）precursors.The preparing conditions including doping concentration of cerium salt and curing temperature of coatings were investigated.The corrosion resistance of Ce-doped silane-based hybrid coatings was compared with non-doped silane-based hybrid films,chromate and RE conversion coatings for 2A12 aluminum alloys in 3.5%NaCl（mass fraction）solution by polarization curve and electrochemical impedance spectroscopy（EIS）,respectively.The results indicated that the polarization resistance value of Ce-doped silane-based hybrid films increased by about 13 times compared with that measured for non-doped silane-based hybrid coating,and is much greater than those of chromate and RE conversion coatings.