Microstructure and electrochemical behavior of TiO2 nanotubes coated on titanium-based substrate before and after thermal treatment

Abstract

The comparative study of the structure and electrochemical properties of TiO2 layers on the surfaces of commercially pure titanium and Ti6Al4V alloy were performed. The TiO2 surface layers produced by anodization in ethylene glycol-based electrolyte solution using Power Supply MCS-3204 MAN-SON at 20 V or 40 V for 60 minutes were formed on the titanium substrates by simultaneous surface oxidation and controlled dissolving of oxide film due the fluorine ions. The SEM and X-ray diffraction analyses were performed to determine the properties of the anodized layers before and after heat treatment at 500 degrees C for 120 minutes. The as-anodized TiO2 nanotubes exhibited an amorphous structure. An anatase phase appeared in annealed nanotube layers of both Ti based substrates. The corrosion behavior in simulated physiological solution was compared for not anodized, anodized and anodized heat treated conditions of both titanium surfaces. The results of the electrochemical measurements corresponded to the microstructure and treatment condition. The porous feature of the anodizing layers on Ti6Al4V substrate led to lower corrosion resistance that increased after the heat treatment.