Abstract
? 2021 Elsevier B.V.The porosity of plasma electrolytic oxidation (PEO) coating limits PEO technology for improving the corrosion resistance of magnesium (Mg) and its alloys. In this study, we innovatively added double magnetic to the PEO process and explored the effects of magnetic field force (MFF) in the process of particle formation in electrolytes, growth of PEO coating on Mg, and coating growth at arcing stage only. Results indicated that MFF greatly improved mixed composition in electrolytes adequately and evenly, reducing the energy of PEO coating formation by increasing the conductivity of the electrolyte, thereby reducing the breakdown voltage, and then reducing porosity (decreasing from 17.52% to 0.58%) and contact angle of PEO coatings. Compared with the nonmagnetic action group, the corrosion current density of the MFF group is decreased by one order of magnitude. The lower porosity would inhibit infiltration of the corrosive medium into the inner regions of the coating and subsequently down to the substrate, thus improving the corrosion resistance of the coating. Mg with PEO coatings prepared under MFF for a long time degrades less than uncoated and other coatings, which makes them more suitable for orthopedic implants.
NSTL
Elsevier