Study on corrosion mechanism of Al-Zn coatings in the simulated polluted marine atmosphere

The corrosion behavior of Al-Zn coatings on steel sheets in simulating polluted marine atmosphere was systematically evaluated by weight loss tests, potentiodynamic polarization curves, electrochemical impedance spectroscopy, and acid salt spray test. The results demonstrated that the AI-Zn coating produced a passivation film of Al2O3 with good corrosion resistance, forming a thick and dense layer of insoluble corrosion products. In addition, the corrosion products such as Zn5Cl2(OH)8.H2O and NaZn4(SO4)Cl(OH)6.6H2O hindered the diffusion of corrosive substances into the coating and thus inhibited further corrosion.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The corrosion behavior of Al-Zn coatings on steel sheets in a polluted marine atmosphere was evaluated using weight loss tests, potentiodynamic polarization curves, electrochemical impedance spectroscopy, and acid salt spray test. The results showed that the Al-Zn coating formed a passivation film of Al2O3 with good corrosion resistance, resulting in a thick and dense layer of insoluble corrosion products. Furthermore, corrosion products such as Zn5Cl2(OH)8.H2O and NaZn4(SO4)Cl(OH)6.6H2O obstructed the diffusion of corrosive substances into the coating, thereby inhibiting further corrosion.