Corrosion resistant evaluation of oxygen solid-solution strengthened pure titanium

Titanium and its alloy have passive state film, which were formed on the surface by oxidation and water in atmosphere. Titanium shows superior corrosion resistance due to the protection of passive state film. Recently, oxygen solid-solution strengthened pure titanium that made by powder metallurgy process is developed to achieve high strength, high ductility and low cost. However, evaluation of corrosion resistant property has not been carried out. For the purpose of evaluating the corrosion resistance of the material quantitatively, we employed electrochemical methods. Four kinds of oxygen solid-solution strengthened pure titanium with different TiO₂ contents (0, 0.6, 1.0 and 1.5 mass%) and pure titanium were prepared. Potentio-dynamic polarization curve measurement and electrochemical impedance spectroscopy were used for these materials. According to the results of polarization curve, corrosion rate of oxygen solid-solution strengthened pure titanium increased with oxygen level. However, it shows approximately equivalent corrosion resistant to pure titanium. The results of electrochemical impedance spectroscopy suggest that the corrosion mechanism of solid-solution strengthened pure titanium is consistent with pure titanium.