摘要

The mechanism of titanium anodization is unclear yet. The total current includes ionic and electronic currents. The ionic current drives oxide film growth and the electronic current causes oxygen bubble emission. Based on a former derivation, a mathematical model of voltage-time transient curves during galvanostatic anodizing under higher current densities (>10 mA/cm(2)) was developed. The high-current model shares the same mechanism of oxide formation with the former low-current model, but the calculation of electric field is different. The results show high accuracy of fitted curves, and prove the linear correlation between nanotube length and ionic current. The two models vary in the applicable ranges, because the relation between ionic currents and electric field is different under high and low field.