Influence of thermal and electrochemical oxidation on the mechanical and corrosion properties of titanium alloy

Abstract

In this paper thermal oxidation and electrochemical anodizing processes were used to produce titanium oxide films on titanium alloy and to examine the effects of oxidation on mechanical and corrosion properties. The surface morphology oxide films, thickness and chemical composition of the surfaces were evaluated using scanning electron microscopy and energy dispersive spectroscopy. The microhardness of titanium oxide films prepared at different experimental conditions is maintained between 8, 2 GPa and 9, 6 GPa, measured by ultra micro hardness tester. The microhardness increased with temperature and voltage. The values of roughness parameters Rz, Rt and Ra indicate a somewhat less roughness of the anodized samples. The values of the roughness parameter Rk are nearly identical for both groups of samples. The cyclic polarization tests showed that none of the tested samples were susceptible to localized corrosion. The oxide films produced by anodic oxidation on titanium alloy showed a higher corrosion resistance than the ones produced by thermal oxidation.