钙铁离子对Cu-Ni-Cr复合镀层耐蚀性影响的研究

Effect of Ca-and Fe-ions on Corrosion Performance of Cu-Ni-Cr Coating

针对某汽车供应商提供的Cu-Ni-Cr镀层试样,采用电化学阻抗、动电位极化曲线等方法,研究了不同钙铁离子浓度以及在特定温度下铁离子对Cu-Ni-Cr镀层耐蚀性的影响。结果表明,在浸泡初期Ca2+对Cu-Ni-Cr镀层起钝化作用对镀层具有一定防护作用,在浸泡中后期,主要以Cl^-的腐蚀作用为主;Fe^(3+)对Cr为加速腐蚀作用,而且随着温度升高会加速Cr的腐蚀,Fe^(3+)对Cu-Ni-Cr镀层的腐蚀反应主要发生在Ni-Cr层。

The effect of solutions of CaCl_2 and FeCl_3 with different Ca-and Fe-ion concentrations respectively on the corrosion performance of Cu-Ni-Cr coating on plastic parts was studied by means of potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed that the Ca-（2＋）may induce passivation of the Cu-Ni-Cr coating surface in the early immersion stage, while the Clas corrosive species playing a major role in the corrosion process in the late-stages. However the Fe-（3＋）can accelerate the corrosion process of the Cu-Ni-Cr coating, and the corrosion rate increased with the increasing temperature. The corrosion reaction mainly occurred at the Ni-Cr interface.