Study on bioactivity of plasma-sprayed titania coating

Titania coatings were deposited on titanium alloy substrates by atmospheric plasma spraying using nano TiO2 powder as feedstock. Acid and alkali solutions were implied to modify the surface of the as-sprayed titania coatings. The bioactivity of titania coatings before and after modification were investigated by simulated body fluid (SBF) tests in vitro. X-ray diffraction, Scanning electron microscope, Fourier transform infrared spectroscope and Energy diffraction spectroscope were used to investigate the microstructure and composition of titania coatings. The bonding strength and anti-corrosion of titania coatings were also studied. The results indicate that the bonding strength between titania coating and Ti alloy substrate is 40MPa. The corrosion resistance performance of titania coating in SBF is better than that of Ti-6Al-4V alloy. The SBF tests show that the carbonate-containing hydroxyapatite is formed on the titania coating surfaces which is treated by H2SO4 and NaOH. However, no bone-like apatite is formed on the surface of as-sprayed titania coating. It is concluded that the bioactivity of titania coating is improved greatly by chemical treatment.