机械镀Zn-Al合金镀层的耐腐蚀性能研究  

Corrosion resistance of Zn-Al alloy coating deposited by mechanical coating

作　　者：赵庆虚 王胜民[1] 赵晓军[1] 赵凯 张国亮[1] ZHAO Qingxu;WANG Shengmin;ZHAO Xiaojun;ZHAO Kai;ZHANG Guoliang(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093

出　　处：《材料科学与工艺》2023年第1期27-34,共8页Materials Science and Technology

基　　金：国家自然科学基金资助项目(52161013)。

摘　　要：为了增强机械镀镀层的耐腐蚀性能,采用机械镀方法,以含铝5%(质量分数)的Zn-Al合金粉为原料,在Q235钢材基体表面制备了Zn-Al合金镀层。利用扫描电镜(SEM)表征了合金镀层的截面和断面形貌;采用极化曲线、电化学阻抗谱(EIS)分析了合金镀层在3.5%NaCl溶液中的电化学行为;通过中性盐雾腐蚀实验分析了合金镀层的耐蚀性,并采用XRD分析了镀层的盐雾腐蚀产物。结果表明,Zn-Al合金镀层由葫芦状的Zn-Al合金颗粒交错互嵌堆积而成,镀层颗粒之间以类似隼接的连接方式搭接“卡锁”;与机械镀Zn层相比,Zn-Al合金镀层的腐蚀电位正移了209 mV,腐蚀电流密度仅为纯Zn镀层的7.1%左右,极化电阻为纯Zn镀层的14倍;Zn-Al合金镀层的容抗弧半径明显大于纯Zn镀层的弧半径,且Q_(dl)较纯锌层减小;纯Zn镀层出现白锈和红锈的时间分别为24和362 h,而Zn-Al合金镀层出现白锈和红锈的时间为48和504 h。Zn-Al合金镀层的耐中性盐雾腐蚀性能明显优于纯Zn镀层,合金镀层对电荷转移具有更好的抑制作用,且Zn-Al合金镀层的腐蚀产物结构致密,可增强物理屏蔽功能。Taking Zn-Al alloy powder containing 5wt.%aluminum as raw material,Zn-Al alloy coating was prepared on the surface of Q235 substrate by mechanical plating method to study the corrosion resistance of mechanical coating.The cross-section morphology and fracture morphology of the alloy coating were characterized by scanning electron microscopy(SEM).The electrochemical behavior of the alloy coating in 3.5%NaCl solution was analyzed by polarization curves and electrochemical impedance spectroscopy(EIS).The corrosion resistance of the alloy coating was analyzed by neutral salt spray corrosion test,and the salt spray corrosion products of the coating were analyzed by X-ray diffraction(XRD).Results show that Zn-Al alloy coating consisted of interlocking Zn-Al alloy particles in the shape of a gourd,and the particles of the coating were interlocked in a way similar to the connection of falcon joints.Compared with mechanical galvanized Zn layer,the corrosion potential of Zn-Al alloy coating was positively shifted by 209 mV,the corrosion current density was only about 7.1%of that of pure Zn coating,and the polarization resistance was 14 times that of pure Zn coating.The capacitive arc radius of Zn-Al alloy coating was significantly larger than that of pure Zn coating,and Q_(dl)was reduced compared with that of pure Zn coating.The time for white rust and red rust to appear in pure Zn coating was 24 and 362 h,while that for white rust and red rust to appear in Zn-Al alloy coating was 48 and 504 h.The neutral salt spray corrosion performance of Zn-Al alloy coating was significantly better than that of pure Zn coating,and the alloy coating had better inhibition effect on charge transfer.The corrosion product structure of Zn-Al alloy coating was dense,which can enhance the physical shielding function.

关 键 词：Zn-Al合金镀层 Zn-Al机械镀 ZN-AL合金 耐蚀性 沉积 

分 类 号：TG170[金属学及工艺—金属表面处理]