Corrosion resistance of benzotriazole passivated Cu-Zn-Al shape memory alloy in artificial Ringer＇s solution

The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole was investigated by salt spraying test and electrochemical methods in artificial Ringer＇s solution. The results showed that after benzotriazole passivation, the corrosion resistance of the Cu-Zn-Al shape memory alloy was improved evidently. The anodic polarization current density of the passivated alloy decreased, the mass loss reduced, the anodic passivation accelerated, the anodic active dissolution was inhibited effectively, and the surface tarnishing was reswained. Infrared reflection spectrum test showed that Cu（Ⅰ）-benzotriazole or Cu（Ⅱ）-benzotriazole complex layer was formed on the surface of the Cu-Zn-Al shape memory alloy after passivation. This layer appeared plane, well adhesion, and presented homogeneous golden metallic luster. The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole is improved for the formation of an electrochemical stable baffle layer on passivated surface. This layer separates the metal substrate from the outside corrosion medium effectively and retards the corrosion process of dezincification.