Electrochemical anodization has become a prevalent surface modification method for biomaterials nowadays. In this study we prepared Ni2O3-doped TiO2 nanotubes (NTs) on NiTi alloy using electrochemical anodization method and explored its suitability for biomedical applications. Morphology, composition and microstructure of NT films were found to depend on preparation conditions. NT film prepared at 35 V, 45 degrees C and 10 min had well-defined nanotubular architecture and were composed of TiO2 and a small amount of Ni2O3. Annealing at 450 degrees C, the film remained amorphous structure, with excellent corrosion resistance. At annealing temperatures of 600 degrees C, rutile crystalline was formed thus enhanced the bioactivity of the film. Formation of NT film on the surface of NiTi alloy also increased its wettability, especially for 600 degrees C annealed sample, so the biological response is expected to be improved. Our results indicate that annealing the NT film coated NiTi alloy at 450 degrees C is desirable for cardiovascular applications. This attributes to its advantages such as the eliminated toxic F species, enhanced corrosion resistance and reduced risk of calcification. For orthopedic applications, annealing at 600 degrees C is preferred due to its enhanced corrosion resistance and bioactivity.

Corrosion; Bioactivity; Nanotubes; Nickel-titanium; Wettability

Taiyuan University of Technology