Influência dos parâmetros operacionais da anodização de liga de titânio nas características dos filmes formados

Abstract

Titanium alloys have been widely used in the biomaterials area, since they have higher mechanical resistance and are more cost-effective than pure titanium. From this perspective, were studied the operational parameters effects on the electrochemical anodization of Ti6Al4V alloy in phosphoric and sulfuric acids solutions. Electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) techniques were used to evaluate the electrochemical aspects of the surface. The characterization of the formed oxide was performed by scanning electron microscopy (SEM) coupled to an energy dispersive spectroscopy (EDS) probe, X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that all anodized samples had high corrosion resistance, due to high values of polarization resistance and corrosion potential and low values of corrosion and passivation current densities as well. The anodized samples in phosphoric acid exhibited the highest values of polarization resistance, while the lowest values were found for films grown in more concentrated sulfuric acid. Moreover, only H2SO4 induced the anatase formation. In H3PO4, films were enriched with phosphorus. Therefore, sequential anodic processes conducted on both electrolytes showed results that may be more suitable for use in implants.