Effect of Micro Arc Oxidation Treatment Time on In-Vitro Corrosion Characteristics of Titania Films on Cp Ti.

Abstract

 Abstract—The present work is aimed at the optimisation of treatment time for the development of an oxide film on commercially pure titanium (Cp Ti) implant material by micro arc oxidation (MAO) process, to improve its corrosion resistance under 7.4 pH simulated body fluid physiological conditions. The MAO treatments were conducted for 4, 8 and 12 min in constant current mode by a DC power supply unit with an aqueous electrolyte solution comprising 15 g/l of tri-sodium ortho phosphate (Na3PO4.12H2O). The phase composition of the fabricated films was analyzed by X-ray diffraction (XRD) technique. The morphology and thickness of the films were determined by scanning electron microscopy (SEM) and the corrosion characteristics were assessed by potentiodynamic polarization technique. The XRD results demonstrated that the oxide films mainly consisted of anatase phase. While the average size of isolated surface pores was in the range of 0.5 to 5 µm, the thickness of the film varied from 24 to 55 µm. A significant improvement in the corrosion resistance was observed for the MAO treated Cp Ti implant material compared to that of the untreated. The surface pore features, the thickness of the film and the corrosion characteristics of the developed films were correlated with the MAO treatment time. Of the three different MAO treatment times employed in the present study, 8 min treatment time was established to be an optimized one for developing oxide films on Cp Ti to provide an optimal surface porosity and to minimise corrosion rate under physiological conditions.