论文部分内容阅读
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 properties of pure zinc and zinc-aluminum pseudo-alloy coating in chloride ion-containing environment were studied by salt spray test and electrochemical impedance spectroscopy. The scanning electron microscopy, X-ray phase analysis and other means were used to study the original The surface morphology of the coating and the corrosion and the phase structure of the corrosion products, and the corrosion mechanism of the two coatings was discussed.With the increase of salt spray time, the surface of the pure zinc coating gradually formed loose porous cellular The corrosion products were mainly composed of Zn5 (OH) 8-Cl2H2O, ZnO and Zn5 (CO3) 2 (OH) 6, and the cracks occurred in the local area of the corrosion product after the salt spray test reached 768 h. (OH) 8Cl2H2O, Zn0.71Al0.29 (OH) 2 (CO3) 0.145.xH2O and ZnAl2O4 on the surface.The results of electrochemical impedance spectroscopy showed that with the extension of salt spray time, The charge transfer resistance of both coatings gradually increased, but the impedance of zinc-aluminum pseudo-alloy coating was significantly greater than the pure zinc coating, showing better corrosion resistance.