Improving surface characteristics of PEO coatings of Mg and its alloys with zirconia nanoparticles: a review
Razieh Chaharmahali, Arash Fattah‐alhosseini, Meisam Nouri, Kazem Babaei
Abstract
Magnesium is known as a suitable biological material because of its biocompatibility and biodegradability. The most important limitation of magnesium and its alloys is their poor corrosion resistance. Having a standard electrochemical potential of -2.38 V, magnesium and its alloys are considered to be the most anodic structural metal compared to the standard hydrogen electrode. Poor corrosion performance of magnesium and its alloys has resulted in a reduction in their chemical stability as well as limited use in corrosive media. One solution to overcome this obstacle is surface modification of these alloys. A variety of coating methods have been studied to provide protection for magnesium and its alloys against corrosion, including PEO. An important parameter in this process is chemical composition of the electrolyte. Changing the condition of the electrolyte based on the presence of particles is one of the beneficial approaches to reduce the porosity of the coating and improve its final behaviors. Suitable properties of zirconia nanoparticle including great mechanical strength, good corrosion resistance in addition to antibacterial properties are the main reasons for its usage. This paper summarizes the findings of the researches on the utilization of zirconia nanoparticles in the PEO coating process of magnesium and its alloys which includes the effect of the nanoparticle on microstructure, corrosion, mechanical and tribological properties of the alloys.