热喷涂Zn-Ni复合涂层在海水中的腐蚀行为研究
2013-06-04 16:24:24
作者：王应发等来源：
摘要：利用喷雾干燥法制备了不同Ni含量的团聚型Zn-Ni复合粉末，并在此基础上用氧乙炔火焰喷涂工艺制备了Zn-Ni复合涂层。通过动电位极化和电化学阻抗测试，并结合SEM、EDS和XRD分析，研究涂层在海水介质中的防护性能和腐蚀机理。结果表明：涂层的自腐蚀电位稳定值在-0.98至-0.95 V，Ni可起到稳定Zn(OH)2，抑制其向疏松ZnO转化的作用，腐蚀产物的堆积使得涂层电阻Rc和电荷转移电阻Rt不断增大，腐蚀电流不断减小；不同Ni含量涂层的耐蚀性存在明显差异，其中Ni含量为20 mass%的涂层耐蚀性能最好。
Abstract：In order to improve the corrosion resistance of coating and prolong its life in the marine environment. Zn-Ni composite coatings including different nickel content were prepared by oxyacetylene flame spraying process, with Zn-Ni composite powders which were prepared by spray-dried process. The protection performance and corrosion mechanism of the Zn-Ni composite coatings in seawater were tested by means of potentiodynamic polarization and electrochemical impedance, and with the analysis of SEM, EDS and XRD. Results shown that the stable corrosive potential of the coatings finally ranges from -0.98 V to -0.95 V. The presence of nickel can play a role that restrain the dense Zn(OH)2 to be converted into the loose ZnO. At the same time, the coatings resistance Rc and charge transfer resistance Rt are both being increased and causing the coatings corrosion current being decreased gradually with the accumulation of corrosion products. Corrosion resistances of these coatings with different nickel content are obviously different, and the anti-corrosion properties of the coating with 20 mass% Ni is best.
Key Word：oxyacetylene flame spraying,Zn-Ni composite coating,potentiodynamic polarization,electrochemical impedance,corrosion resistance
Abstract：In order to improve the corrosion resistance of coating and prolong its life in the marine environment. Zn-Ni composite coatings including different nickel content were prepared by oxyacetylene flame spraying process, with Zn-Ni composite powders which were prepared by spray-dried process. The protection performance and corrosion mechanism of the Zn-Ni composite coatings in seawater were tested by means of potentiodynamic polarization and electrochemical impedance, and with the analysis of SEM, EDS and XRD. Results shown that the stable corrosive potential of the coatings finally ranges from -0.98 V to -0.95 V. The presence of nickel can play a role that restrain the dense Zn(OH)2 to be converted into the loose ZnO. At the same time, the coatings resistance Rc and charge transfer resistance Rt are both being increased and causing the coatings corrosion current being decreased gradually with the accumulation of corrosion products. Corrosion resistances of these coatings with different nickel content are obviously different, and the anti-corrosion properties of the coating with 20 mass% Ni is best.
Key Word：oxyacetylene flame spraying,Zn-Ni composite coating,potentiodynamic polarization,electrochemical impedance,corrosion resistance
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