Nanostructured merwinite bioceramic coating on Mg alloy deposited by electrophoretic deposition

Magnesium (Mg) alloys have recently attracted much attention as degradable metallic implants for bone fracture healing. A biodegradable osteosynthetic implant material will remove the need for the implant removal surgery after the bone healing process. However, the high corrosion rate of the Mg alloys in the body fluid has prevented their clinical application as implants. In the present study, a nanostructured merwinite (Ca3MgSi2O8) bioceramic coating was prepared on AZ91 Mg alloy in order to improve its corrosion resistance, bioactivity, mechanical stability and cytocompatibility. The coating was deposited by electrophoretic deposition assisted micro arc oxidation. The phase composition and the surface morphology of the samples were characterized by X-ray diffraction and electron microscopy. The corrosion, bioactivity and mechanical behavior of the samples were investigated by electrochemical measurements, immersion into simulated body fluid (SBF) and compression tests. The cytocompatibility of the samples was evaluated by a cell culture test. The results showed that the nanostructured merwinite coating not only improved the corrosion resistance, but also enhanced the bioactivity, mechanical stability and cytocompatibility of the AZ91 Mg alloy.