A ceria/calcium-phosphate functional composite coating on magnesium alloy for enhanced adhesion strength, corrosion resistance, and biocompatibility

Magnesium (Mg) and its alloys have been regarded as potential orthopedic implant materials due to their suitable properties but face challenges due to rapid biocorrosion and insufficient bio-functionality, necessitating surface treatment to mitigate dysfunction. In this work, a two-step electrodeposition was employed to construct a ceria/calcium-phosphate (Ce/Ca-P) composite coating on Mg alloys. This construction approach endows multi-functions of the coating. The ceria interlayer ameliorates adhesion strength. The pin-like structure on the outer layer of the Ce/Ca-P coating enhances the antibacterial capabilities of the coating in the early stages of the implantation. The calcium-phosphate outer layer and the ceria interlayer induce the deposition of calcium and phosphate ions promoting bone healing in the mid-term. The introduction of the ceria interlayer significantly reduces the corrosion rate of the Mg alloy by 86.7% improving the corrosion resistance of the alloy, which is of great significance to maintain the service reliability of the device during the long-term service period. The results indicate that the Ce/Ca-P coating exhibits good hemocompatibility and cytocompatibility. This type of developed coating with anti-corrosive and bio-functionalized capability helpfully advances the application of Mg-based bone implants.