Corrosion and tribocorrosion resistance of MAO-based composite coating on AZ31 magnesium alloy

In this paper, a multi-functional composite coating with low friction coefficient, high wear resistance and excellent tribocorrosion resistance is fabricated on AZ31 Mg alloys by micro-arc oxidation and spray-coating methods. The microstructure, and composition of the coating are characterized by SEM, EDS, XRD, and FT-IR. Potentiodynamic polarization and EIS tests are conducted to evaluate the corrosion resistance of the composite coating. The tribocorrosion property is also studied using pin-on-disk tribometer in 3.5 wt.% NaCl solution. It is found that the composite coating possesses better long-term corrosion resistance than the single MAO coating. The tribocorrosion tests prove that the composite coating exhibits much better wear and tribocorrosion resistance than the single MAO coating and can protect the substrate from corrosion under a sliding condition. (c) 2021 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under responsibility of Chongqing University

Automated summary

In this paper, a multi-functional composite coating with low friction coefficient, high wear resistance, and excellent tribocorrosion resistance is fabricated on AZ31 Mg alloys. The composite coating exhibits better long-term corrosion resistance and wear and tribocorrosion resistance compared to the single micro-arc oxidation (MAO) coating. It can effectively protect the substrate from corrosion under sliding conditions.