镁合金表面无机-有机杂化硅膜的制备及其防护性能研究  

Preparation and Protective Properties of Inorganic-organic Hybrid Silane-coatings on Mg-alloy AZ31

作　　者：张新芳 欧孝通[1] 刘雷 雷惊雷[1] 李凌杰[1] 

机构地区：[1]重庆大学化学化工学院,重庆400044

出　　处：《中国腐蚀与防护学报》2017年第5期435-443,共9页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金(21273293和21573028);重庆市杰出青年基金(cstc2014jcyjjq100004);中央高校基本科研业务费(106112016CDJZR225515)~~

摘　　要：通过在正硅酸乙酯水解过程中加入硅烷偶联剂得到了杂化硅溶胶,进而采用提拉法在AZ31镁合金表面制备了无机-有机杂化硅膜。利用SEM和AFM观察了膜层的表面形貌,利用XPS和FT-IR分析了膜层的组成,通过动电位极化曲线和EIS研究了膜层的防护性能。结果表明,杂化膜层均匀、致密,完整覆盖在镁合金基体表面;杂化膜层的阻值(1.717×10~4Ω·cm^2)大于传统铬酸盐转化膜的阻值(1.611×10~4Ω·cm^2),样品的腐蚀电流密度相对于裸金属的下降了约2个数量级。硅烷偶联剂的位阻效应可以有效调节传统的正硅酸乙酯水解缩聚过程,使形成的杂化硅溶胶在成膜时不易产生团簇,保证了膜层的致密完整,从而能够很好地阻挡腐蚀介质的渗透,对镁合金发挥良好的防护作用。The hybrid silane sol was prepared by adding silane coupling agent in the hydrolyzing tetraethyl orthosilicate（TEOS）,and then the organic-inorganic hybrid silane-coating was successfully prepared on the AZ31 Mg-alloy using a simple dip-coating method.The morphology and composition of the hybrid coating were characterized by scanning electron microscopy（SEM）,atomic force microscopy（AFM）,energy dispersion spectroscopy（EDS）,X-ray photoelectron spectroscopy（XPS） and Fourier transform infrared spectroscopy（FT-IR）.Moreover,the corrosion resistance of the hybrid silane-coating was studied by means of potentiodynamic polarization and electrochemical impedance spectroscopy（EIS）.The results showed that the Mg-alloy substrate was completely covered with organic-inorganic hybrid silane-coating,which was uniform and compact.The resistance of the hybrid silane-coating（1.717×10^4Ω·cm^2） is higher than that of the conventional chromate conversion coating（1.611×10^4Ω·cm^2）,and correspondingly,the corrosion current density of the AZ31 alloy with coating is about 2 orders of magnitude lower than that of the bare alloy.The steric effect of the silane coupling agent can effectively adjust the traditional hydrolysis polycondensation process of TEOS and prevent the hybrid silane sol from further clustering.The as-prepared coating is compact and uniform,which can resist the corrosive medium and provide excellent protection for Mg-alloy.

关 键 词：镁合金 杂化硅膜 耐蚀性能 成膜机制 

分 类 号：TG174.46[金属学及工艺—金属表面处理]