钛和铈对热浸锌镀层组织与耐蚀性能的影响

为了获得厚度适中、耐蚀性能好的热浸镀锌层,在锌浴中添加微量的Ti和Ce,分别在Zn-0.04%Ti、Zn-0.02%Ce和Zn-0.04%Ti-0.02%Ce镀浴中制得热浸锌合金镀层.采用金相显微分析以及电化学阻抗谱、电化学极化测试、中性盐雾试验,研究了Ti和Ce对镀层组织和耐蚀性能的影响.结果表明:在锌浴中添加0.0...

Effects of titanium and cerium on microstructure and corrosion resistance of hot-dip galvanized coating

A small amount of Ti and Ce was added to the zinc bath,to produce hot-dip galvanized coatings with moderate thickness and good corrosion resistance. Three coatings were obtained from the baths of Zn-0.04%Ti,Zn-0.02%Ce and Zn-0.04%Ti-0.02%Ce,respectively. The alloy coatings were examined by metallographic analysis,and the effects of Ti and Ce on the corrosion resistance were studied by electrochemical impedance spectroscopy,electrochemical polarization and neutral salt spray test. The thickness of ζ phase was found to be reduced markedly when 0.04% Ti is added to the pure Zn bath,but the phenomenon was not obvious when 0.02% Ce added to the pure Zn or Zn-0.04%Ti bath. Compared with the pure zinc coating,the coatings obtained from Zn-0.04%Ti and Zn-0.04%Ti-0.02%Ce baths have higher electrochemical impedance,positive shift of self-corrosion potential,lower corrosioncurrent density,larger polarization resistance and better corrosion resistance in 5% NaCl solution,and the coating obtained from the Zn-0.04%Ti-0.02%Ce bath has the best corrosion resistance. The addition of Ti and Ce to the zinc bath suppresses the anodic and cathodic processes of corrosion reaction to some extent,and slows down the formation of white rust,improving the corrosion resistance of hot-dip galvanized coating.