Nanostructured Sr, Nb-Incorporated TiO₂ as an Efficient Orthopedic Implant Coating with Superior Bioactivity and Corrosion Resistance

The present work aims to explore the effect of Sr and Nb ions in enhancing bioactivity and corrosion resistance of the implant when incorporated into TiO₂ matrix. This involved the development of nanoporous adherent Sr, Nb-incorporated TiO₂ coating by sol-gel method and spin coating technique. The coating material was characterized by various surface characterization techniques such as attenuated total reflectance-Infrared spectroscopy (ATR-IR), x-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The coating material was identified to be crystalline titania with incorporated Sr and Nb. The bioactivity of the material was confirmed by in vitro bioactivity study. Excellent HAp growth with a particle size of around 1.35 µm was observed on the coated specimens in SEM images taken on the 14th day of study. Electrochemical analysis of the coatings revealed the barrier property of the coating as it has extended passivation region and increased breakdown potential value, which is + 420 mV more at + 695 mV compared to the uncoated specimen at + 275 mV. The results confirm that the crystalline nanoporous Sr, Nb-incorporated TiO₂ coating is multifunctional with better corrosion resistance and enhanced bioactivity and the improved results are a direct result of the incorporation of Sr and Nb ions.