Formation of nano-structured oxide layers formed on Ti-Fe alloys by anodization

Abstract

The present work reports the anodization of Ti-Fe alloys in a fiuoride-containing ethylene glycol electrolyte and the morphology of resulting anodic oxide layers. The current density generated during the anodization at voltages ranged from 10 V to 50 V significantly decreases in the early stage, then increases once and finally exhibits gradual decrease with time although the magnitude of the current depends on the alloy composition. On pure Ti and Ti-10 at% Fe alloy, anodic oxide layers show a nanotubular structure at all applied voltages. On the other hand, at lower voltages, nanotubular oxide layers are also formed on Ti-50 at% Fe and Ti-70 at% Fe alloys, but at higher voltages the morphology of anodic oxide layers changes to an irregular-shaped porous structure. These results indicate that the morphology of anodic oxide layers is affected not only by the alloy composition but also by applied voltage.