Corrosion behavior and antifouling ability of Cu-Zn-Al/Zn-Al composite coating on Q235 steel

Abstract In this study, a Cu-Zn-Al/Zn-Al coating was prepared on Q235 steel by a dip-spin method and the corrosion behavior of the composite coating was also analyzed. The evolution of morphology and phase structure proved the corrosion products transited from the Zn-containing to Al-containing. The potential dynamic results manifested that the corrosion current density of the coated sample (1.42 × 10−6 A·cm2) is two orders of magnitude lower than the substrate. From the impendence plots, it can be found that the impendence resistance of the original Cu-Zn-Al/Zn-Al coating is up to 1.58 × 104 Ω·cm2 due to the existence of the silane and oxide film. With increasing exposure time of aggressive environment, the resistance decreased and then gradually rise to approximately 1.0 × 104 Ω·cm2. Besides, the results of the antifouling test showed the copper leaching remained at a stable value of about 20 μg·cm−2·d−1 which could inhibit most algae, eventually up to 95% lethal effect on N. closterium.