Effect of Ti–OH formation on bioactivity of vacuum plasma sprayed titanium coating after chemical treatment

The effect of Ti–OH groups on bioactivity of NaOH treated titanium coating was investigated in this paper. The NaOH-heat treatment was also applied to modify the titanium coating for comparison. The results show that the amount of Ti–OH groups was important to induce apatite formation on the treated titanium coating. When the NaOH treated titanium coating was exposed to SBF, it released Na+ ions from the sodium titanate layer on its surface into the SBF via exchanging with H3O+ ions in the fluid and Ti–OH groups were rapidly formed on the surface. So the NaOH treated titanium coating has good bioactivity in simulated body fluid (SBF). The amount of Ti–OH groups on the titanium coating was reduced after heat treatment, so the bioactivity of NaOH-heat treated titanium coating was obviously affected.