Fabrication and Performance of ZnO Doped Tantalum Oxide Multilayer Composite Coatings on Ti6Al4V for Orthopedic Application

Ti6Al4V titanium alloy has been widely used as medical implant material in orthopedic surgery, and one of the obstacles preventing it from wide use is toxic metal ions release and bacterial implant infection. In this paper, in order to improve corrosion resistance and antibacterial performance of Ti6Al4V titanium alloy, ZnO doped tantalum oxide (TaxOy) multilayer composite coating ZnO-TaxOy/Ta(x)Oy/TaxOy-TiO2/TiO2/Ti (ZnO-TaxOy) was deposited by magnetron sputtering at room temperature. As a comparison, monolayer TaxOy coating was prepared on the surface of Ti6Al4V alloy. The morphology and phase composition of the coatings were investigated by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), the elemental chemical states of coating surfaces were investigated by X-ray photoelectron spectroscope (XPS). The adhesion strength and corrosion resistance of the coatings were examined by micro-scratch tester and electrochemical workstations, respectively. The results show that the adhesion strength of multilayer ZnO-TaxOy coating is 16.37 times higher than that of single-layer TaxOy coating. The ZnO-TaxOy composite coating has higher corrosion potential and lower corrosion current density than that of TaxOy coating, showing better corrosion inhibition. Furthermore, antibacterial test revealed that multilayer ZnO-TaxOy coating has a much better antibacterial performance by contrast.