Optimization of TiO2 nanotubes synthesis on cylindrical surfaces for bio-implants

Titanium based modified surfaces with TiO2 self-organized nanotubular layers for biomedical applications were synthesized on cylindrical surfaces by electrochemical anodization in phosphate/fluoride electrolytes. Cylindrical samples of φ 3.8 x 20 mm, made of Ti6Al4V alloy, with different initial surface preparation (machined, grinded, polished) were subjected to anodization and process parameters were optimized to assure the development of uniform titania nanotubular layers with nanotubes’ diameter of 25-100 nm. Optimal process parameters in our custom-built anodization cell are: electrolyte composition 1M H3PO4 + 0.4 wt% HF, anodization potential U = 24 V, potential ramp Ur = 0.08 V/s, distance anode-cathode d = 15 mm, current density in potentiostatic stage J = 35-50 A/m2, and anodization duration t = 30-35 min.