Biodegradable Magnesium Alloy-Based Composites: Properties, Processing, and Surface Coatings-A Review

Magnesium (Mg) alloys have recently gained massive attention as a biodegradable implant material. The biocompatibility and high strength-weight ratio make them a competent candidate for degradable implant applications like cardiovascular stents, bone plates, screws, etc. However, the rapid corrosion and consequent hydrogen gas evolution limit the extensive application of Mg alloys and composites as implant material. The excessive hydrogen gas evolution might affect the surrounding implantation tissues due to the formation of gas cavities. The rapid corrosion rate might fail the implant before the expected service time leading to incomplete healing of the tissues. To overcome these shortcomings, methods like heat treatment, surface processing techniques, surface modification operations like surface coatings, and composite development with the addition of reinforcements are done. The current review highlights the recent advancements in the processing techniques and surface treatments of Mg-based metal matrix composites used for bioimplant applications.