Improvement in bioactivity and corrosion resistance of Ti by hydroxyapatite deposition using ultrasonic mechanical coating and armoring

In the present work, nanostructured hydroxyapatite (HA)-containing coating was prepared on a Ti surface by ultrasonic mechanical coating and armoring (UMCA). A Ti plate was pre-coated with HA slurry, followed by UMCA, which was achieved by high-frequency ZrO2 ball bombardment. The UMCA process comprised several cycles of pre-coating and ball bombardment, providing high amounts of HA and good coating adhesion. The coating mainly consisted of nano-HA particles (less than 10 nm) and a small amount of Ti. Furthermore, the deformation structures of the Ti surface region were characterized in a nanocrystalline layer with a grain size of 50–200 nm. Additionally, the coating exhibited improved bioactivity and corrosion resistance in Hanks' balanced salt solution than the Ti surface. Furthermore, the in vitro cytotoxicity test assessed that the HA-containing coating was non-cytotoxic.