Impressive strides in amelioration of corrosion and wear behaviors of Mg alloys using applied polymer coatings on PEO porous coatings: A review

Abstracts: Magnesium (Mg) and its alloys have received much attention in a lot of areas due to their special chemical and physical properties. Nevertheless, high corrosion rates are a limiting factor. The plasma electrolytic oxidation (PEO) technique is a simple approach to place an oxide film on the surface of light metals like Mg alloys. This method has been considered for controlling the rate of corrosion and improving some other properties. On the other hand, PEO coatings cannot make enough protection of Magnesium alloys for a long time due to porosity and fine cracks. Therefore, PEO-based composite coatings are used to make adequate corrosion protection on the Mg alloys surface. The popularity of these coatings is due to their good corrosion resistance, simplicity, high coating capability, and cost-effectiveness in complex segments. Formation of an organic layer on the surface of PEO coating is one of the effective methods to close the defects and thus prevent the corrosive species penetration into the substrate. Coating the PEO coating with a polymer layer can be a good solution to control the amount of damage and improve the corrosion and abrasion resistance. In addition, PEO coating can eliminate the problems of insufficient adhesion of polymer coatings and is considered as a suitable base for composite coatings. This review paper presents the corrosion and abrasion behavior of the PEO/Polymer dual coating system on Mg alloys. Given the fundamental role of coatings thickness and morphology in wear and corrosion behavior, these aspects have been highly discussed in this study.