Plasma electrolytic oxidation (PEO), as a cost effective and environmentally friendly technology, has been applied on magnesium and its alloys to improve wear and corrosion resistance. Additionally, combining with particles addition in the electrolyte and/or various post-treatments could diminish the intrinsic structural defects of the PEO coatings and provide multifunctionalities, including wear resistance, corrosion resistance, self-lubrication, and self-healing. This paper reviews recent progress on PEO composite coatings prepared by in situ incorporation of functional particles and/or post-treatments on magnesium and its alloys. The focus is given to the microstructural and functional changes of the PEO coatings, particularly on the wear and corrosion behaviors.

Corrosion problems are widespread in nature. As one of the most convenient and efficient methods for metal anticorrosion protection, anticorrosive coatings have received increasing attention. With the continuous advancement of science and technology, more novel functional anticorrosion coatings are being extensively researched. This review provides an overview of recent research progress in anticorrosion coatings and functionalized modified materials. Recent methods for performance optimization can be categorized into three main sections: modification by nanoparticles, modification by carbon-based materials, and specific functionalization (barrier effect, passivation, shielding effect, resistivity, self-repair). Through modification, the anticorrosion performance of coatings is significantly enhanced, with impedance levels improving by up to three orders of magnitude. Furthermore, modification imparts additional outstanding features to the coatings, such as high-temperature resistance, thermal conductivity, self-healing, and hydrophobicity. Finally, the future development trend of anticorrosion coatings is proposed, and several reasonable suggestions are put forward for the challenges faced.