LAUSR

Abstract Sol-gel coating hydroxyapatite (HA) allows for non-line-of-sight coatings on metallic implants that enhance biocompatibility and osseointegration, but coatings are on the order of a few microns thick and have poor adhesion, especially at low sintering temperatures; Both issues can limit implant longevity. In order to improve coating adhesion strength, a titania nanotube interface was used to reduce thermal mismatch and provide a nano-scale surface morphology for mechanical interlocking, while multiple dip-coatings achieved coating thicknesses >70 μm. In this study, Ti-6Al-4V disks were anodized to produce self-assembled titania (TiO2) nanotubes (NTs) on the surface of the substrates, while HA sol-gel was used to dip-coat the samples. The titania layers measured 800–900 nm thick, with nanotube pore widths of 90 ± 12 nm. Pure HA coating thicknesses were measured at 73.3 ± 10.5 μm and 84.97 ± 18.1 μm for polished Ti-6Al-4 V and anodized Ti-6Al-4V, respectively. The adhesion strengths of pure HA coatings on anodized (NT) surfaces were significantly higher (P