Characterization, Corrosion Resistance, and Cell Response of High-Velocity Flame-Sprayed HA and HA/TiO2 Coatings on 316L SS

The main aim of this study is to evaluate corrosion and biocompatibility behavior of thermal spray hydroxyapatite (HA) and hydroxyapatite/titania bond (HA/TiO₂)-coated 316L stainless steel (316L SS). In HA/TiO₂ coatings, TiO₂ was used as a bond coat between HA top coat and 316L SS substrate. The coatings were characterized by x-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy, and corrosion resistance determined for the uncoated substrate and the two coatings. The biological behavior was investigated by the cell culture studies using osteosarcoma cell line KHOS-NP (R-970-5). The corrosion resistance of the steel was found to increase after the deposition of the HA and HA/TiO₂ bond coatings. Both HA, as well as, HA/TiO₂ coatings exhibit excellent bond strength of 49 and 47?MPa, respectively. The cell culture studies showed that HA-coated 316L SS specimens appeared more biocompatible than the uncoated and HA/TiO₂-coated 316L SS specimens.