Abstract: In this work, a biomimetic coating of hydroxyapatite (HA)-and titania (TiO2) was deposited on low elastic β-phase Ti-35Nb-7Ta-5Zr (β-TNTZ) alloy by plasma spray deposition technique for orthopedic applications. The effect of TiO2 reinforcement on microstructure, mechanical properties, and bioactivity was investigated. The morphology, coating thickness, elemental composition, and phase composition of the developed coatings were characterized. The biomechanical behavior of the deposited coatings was investigated in terms of surface hardness, elastic modulus, and adhesion strength. It was found from the morphological investigation that the TiO2 reinforcement improves the microstructure and prevents the formation of defects in the coating. The biomimetic HA-TiO2 coated surface possessed pores, size ranging from 200 nm – 600 nm that benefits the apatite growth and osseointegration. The EDS spectrum, mapping, and XRD analysis show that the deposited layer β-TCP, CaO, TTCP, TiO2 phases. The HA-TiO2 coating exhibits a very dense and thick layer of 100 μm – 125 μm that exhibits excellent adhesion strength to offer mechanical interlocking to prevent delamination. The alloying of TiO2 improves the hardness from 1.67 GPa to 2.95 GPa that enhances the wear resistance. It was found that HA-TiO2 coating exhibits better hydrophilic and biocompatible surface as compared to HA-coating.

Key words: β-phase Ti-35Nb-7Ta-5Zr alloy, plasma spray, porosities, bio-ceramic coating, nano-indentation, hardness, bond strength, wettability