Ti6Al4V alloy is widely used as an implant in medical engineering due to its suitable biocompatibility properties. On the other hand, due to clinical and orthopedic concerns about the severe release of metal ions and their destructive effects on the body, it is necessary to cover this alloy. Zinc oxide offers many benefits such as low toxicity, high corrosion resistance and biocompatibility. In addition, zinc oxide is able to create a diverse set of surface morphologies that affect its antimicrobial and biological properties. The presence of bioactive glass particles in the structure of zinc oxide causes the release of hydroxyapatite on its surface, thus creating a higher biocompatibility for this coating. In the present study, a zinc oxide composite coating containing bioactive glass particles was created by electrically depositing on a Ti6Al4V alloy substrate. The effect of changes in electrical deposition potential and concentration of bioactive glass nanoparticles in electrolyte containing 0.1 M zinc nitrate on the nucleation and growth process, and properties of the resulting coatings were investigated. Surface, mechanical, electrochemical and bioactive properties of the coated samples were eva‎luated at potentials of -1.2 and -1.4VAg /AgCl and in the bath containing of 0, 0.5 and 1% of bioactive. Coatings formed at a concentration of 1% bioactive glass at both potentials with uniform morphology and an average thickness of 6μm were introduced as optimal specimens in terms of morphology and thickness and their surface properties including surface roughness, wettability and adhesion to the substrate were eva‎luated and with samples of the same conditions in the absence of bioactive glass were compared. For all these coatings, short-term and long-term electrochemical impedance spectroscopy test in phosphate buffer salt solution was performed. The coating created at the potential of -1.2VAg/AgCl at a concentration of 1% of bioactive glass achieved to a total resistance of 18.23 M.cm2, at the end of the 28-day immersion period and had the highest barrier performance against corrosive products among other coatings. This coating also provided ideal performance in terms of medium surface roughness (1.55 μm), high wettability (25.5º) and high adhesion of the coating to the substrate (12 MPa). Immersion of both coated samples in the potential of -1.2 and -1.4VAg /AgCl at a concentration of 1% bioactive glass in the simulated body fluid for 28 days causes maximum absorption of Ca and P ions in the solution and formation of homogeneous layers of hydroxyapatite on the surface. In general, the coatings created under the conditions of -1.2 and -1.4VAg /AgCl at a concentration of 1% of bioactive glass showed the best long-term bioactivity by reducing calcium and phosphorus ions in the simulated body fluid below 5%.

كيوان رئيسي

محمود منيرواقفي، مهشيد خرازيها