摘要
采用盐雾试验和电化学阻抗谱测试技术研究了纯锌和锌铝伪合金涂层在含氯离子环境中的腐蚀行为和电化学特性,通过扫描电镜、X射线物相分析等手段研究了原始涂层及腐蚀后的表面形貌和腐蚀产物的相结构,并对两种涂层的腐蚀机理进行了初步的探讨.随着盐雾时间的增加,纯锌涂层表面逐渐生成疏松多孔的胞状腐蚀产物层,主要腐蚀产物为Zn5(OH)8-Cl2H2O、ZnO和Zn5(CO3)2(OH)6,盐雾试验达到768 h后腐蚀产物层局部区域发生龟裂.锌铝伪合金涂层表面生成致密的腐蚀产物层,主要为Zn5(OH)8Cl2H2O、Zn0.71Al0.29(OH)2(CO3)0.145.xH2O及ZnAl2O4.电化学阻抗谱测试结果表明:随着盐雾时间的延长,两种涂层的电荷转移电阻均逐渐增大,但锌铝伪合金涂层的阻抗要明显大于纯锌涂层,表现出了更好的耐蚀性.
The corrosion behavior and electrochemical characteristics of pure Zn and Zn-A1 pseudo-alloy coatings in chlorine ion- containing environment were investigated by salt spray test and electrochemical impedance spectroscopy （EIS）. The surface morpholo- gies and phase compositions of the coatings and the corrosion products were analyzed by scanning electron microscopy （SEM） and X- ray diffraction （XRD）. A preliminary discussion was carried out on the corrosion mechanisms of the two kinds of the coatings. It is found that the corrosion product layer on the pure zinc coating sample is loose and porous with prolonging test time, the main corrosion products are Zn5 （OH）sCl2H2O, ZnO and Zn5 （CO3 ）2 （0H）6 , and some areas in the corrosion product layer have cracked after salt spray testing for 768 h. A compact corrosion product layer forms on the zinc-aluminum pseudo-alloy coating with the time prolonging, and the main corrosion products consist of Zn5 （ OH ） s C12 H2O, Zn0.71 Al0.29 （OH） 2 （ CO3 ） 0.145·xH2O and ZnA12O4. EIS results indicate that the charge transfer resistance of the two coatings increases during the corrosion process. The impedance of the zinc-aluminum pseu- do-alloy coating is significantly greater than that of the pure zinc coating, showing a better corrosion resistance.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2012年第9期1054-1060,共7页
Journal of University of Science and Technology Beijing
基金
国家自然科学基金资助项目(50871021)
关键词
锌合金
铝合金
涂层
耐蚀性
盐雾试验
电化学阻抗谱
zinc alloys
aluminum alloys
coatings
corrosion resistance
salt spray test
electrochemical impedance spectroscopy
作者简介
通信作者:刘安强,E-mail:liuaq509@yahoo.cn
