Effect of Ca/P Ratio on Bioactivity of PEO Coatings

Ti and its alloys are used in biomedical applications because of their low density, high specific strength, and high biocompatibility. However, the poor bioactivity limits their wide application. Herein, ceramic coatings containing Ca and P were prepared by plasma electrolytic oxidation（PEO） on Ti6Al4V alloy, and the microstructure, surface morphology, and chemical composition of these coatings were evaluated. An effect of the different Ca/P ratios in the electrolyte on the CaTiO3-forming ability was investigated; besides, the effect of different Ca/P ratios in these coatings on the hydroxyapatite-inducing potency was also investigated. In addition, the bioactivity of the coatings was compared between before and after the immersion in a simulated body fluid. It was found that the higher the Ca/P ratio in the electrolyte, the stronger the CaTiO3-forming ability, and the higher the Ca/P ratio in the coating, the better the bioactivity of the coatings