Fabrication and Microstructure Analysis of Phosphate-Coated Mg Powder for Biomedical PLA/Mg Composites

Powdered magnesium has been widely applied in various fields. Magnesium is a highly reactive metal, with fine particles that are easy to agglomerate and have the risk of explosion. Furthermore, the storage of Mg particles is a challenge. Therefore, powdered magnesium is usually passivated by surface modification methods. In our research, an environmentally friendly phosphate solution was used to prepare conversion coating on magnesium particles. The results demonstrated that the phosphate coating layer attached on Mg particles surface successfully. From SEM images, the average particle size reduces slightly after the coating process. The composition of the coating layer is confirmed to be OCP and HAp by XRD and EPMA. The immersion test showed that the phosphate coating improved the corrosion resistance, and the ideal processing time is 20 min. Moreover, Mg and phosphate have good biocompatibility; therefore, the coated Mg powder can be a potential candidate for biomedical applications.