Characterization of hydrothermally treated anodic oxides containing Ca and P on titanium

In this study, the formation of hydroxyapatite (HA) by a series of hydrothermal treatment and properties of the anodic oxide films and HA composite coatings were investigated. Based on the observations using EPMA, SEM, and X-ray diffraction, these needles were suggested to have a HA-like structure and were formed on the anodic oxide surfaces. The formation of these apatite-like needles were either oriented at an angle or formed on porous anodic oxide films. The concentration of Ca and P were enriched in apatite-like needles after hydrothermal treatments, whereas lower concentration of Ca and P were observed on anodic oxide film, particularly around the needles. In conclusion, HA-like needles were formed after hydrothermal treatment at 200 and 300 °C.