Corrosion and Bioactivity Properties of Calcium-phosphate PEO Coating on AZ۳۱ Mg Alloy Reinforced by Forsterite (Mg۲SiO۴) Nanoparticles

In this study, for the first time, the Forsterite (Mg۲SiO۴) nanoparticles (NPs) with the size of about ۲۵ nm were added to the phosphate-based electrolyte, and the characteristics and properties of the obtained plasma electrolytic oxidation (PEO) coating on AZ۳۱ Mg alloy was investigated. The results of the potentiodynamic polarization measurements revealed that after one week of exposure to simulated body fluid (SBF) solution, the coating with Mg۲SiO۴ NPs possessed ۱۲.۳۰ kΩ cm۲ polarization resistance, which was more than two times greater than that of the coating without NPs. The thicker coating layer, lower wettability, and also presence of Mg۲SiO۴ NPs inside the pores were responsible for enhanced corrosion protection in the Mg۲SiO۴ NPs incorporated coating. After three weeks of immersion in SBF solution, the in-vitro bioactivity test results indicated the ability of the NPs-containing coating to form apatite (Ca/P ratio of ۰.۹۲) was weaker than the coating without NPs (Ca/P ratio of ۱.۱۷). This could be attributed to the lower wettability of the coating with NPs and supports that the addition of the nanoparticles is not beneficial to the bioactivity performance of the coating.

کلیدواژه ها:

AZ۳۱ Mg alloy ، plasma electrolytic oxidation (PEO) ، Forsterite (Mg۲SiO۴) ، corrosion ، bioactivity.