Effect of calcium-ion implantation on the corrosion resistance and bioactivity of the Ti6Al4V alloy

The corrosion resistance and bioactivity of Ti6Al4V alloy after calcium-ion implantation were examined. Polished samples were implanted with a dose of 1017 Na+/cm2 at a beam energy of 25 keV. The chemical composition of the surface layer formed during the implantation was determined by XPS and SIMS. The bioactivity of the samples was evaluated by soaking them in a simulated body fluid (SBF) at 37 °C for 168 and 720 h. The corrosion resistance in SBF at 37 °C was determined by electrochemical methods after exposure in SBF for various times. The surfaces of the samples before and after examinations were observed by optical microscopy, SEM-EDS and AFM.The results of the corrosion examinations indicated that under stationary conditions and after short-term exposures, the calcium-ion implanted titanium alloy had an increased corrosion resistance, but during the anodic polarization, calcium-implanted samples underwent pitting corrosion. The microscopic observations show that the precipitations of calcium phosphates are present on the surface, but they do not form a continuous layer.