Sol-gel preparation, corrosion resistance and hydrophilicity of Ta-containing TiO2 films on Ti6Al4V alloy
(1. Key Laboratory of Biomedical Information Engineering of Ministry of Education,
School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China;
2. School of Medicine, Xi’an Jiaotong University, Xi’an 710061, China)
School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China;
2. School of Medicine, Xi’an Jiaotong University, Xi’an 710061, China)
Abstract: Ta-containing TiO2 films with Ta contents of 5%, 20%, 33% (mole fraction) were sol-gel coated on the surface roughened Ti6Al4V alloy by dip coating method for biomedical applications. The Ta-TiO2 films on 1.5 mol/L NaOH-HCl pretreated substrate are adherent, but there are cracks for the sample with 33% Ta. X-ray photoelectron spectroscopy results show that Ti and Ta exist as TiO2 and Ta2O5 in the film, and Al element is not detectable. X-ray diffraction and Raman scattering analyses reveal that the addition of Ta decreases crystallization of the films. Potentiodynamic polarization test in a Ca-free Hank’s balanced solution demonstrates that the coating samples markedly improve the corrosion resistance compared with the polished sample. The addition of Ta impedes UV light-induced hydrophilic conversion of the coating samples. The sample with 20% Ta has enough film integrity and hydrophilic conversion rate, and is expected to possess good biological properties.
Key words: titanium; TiO2; sol-gel; tantalum; corrosion; hydrophilicity