Enhancement of Local Corrosion Resistance of CP-Titanium in H2SO4 Solution via Plasma Electrolytic Oxidation

TiO2 coating was produced in single step and during a short time (10 min) by plasma Electrolytic Oxidation (PEO). In this study corrosion behavior of the CP-Ti and PEO coated sample were evaluated. Phase composition and surface morphology of the coating were studied by XRD and SEM respectively. X-ray diffraction result shows that the coating is consist of Anatase and the rutile is not formed under coating formation circumstances. Additionally, coatings demonstrate porous structure which contains micro-pores which are formed as a result of sparking process. Open circuit Potential and Cyclic potentio dynamic polarization tests were carried out in a de-aerated solution of 40 g l-1 H2SO4 and 40 g l-1NaCl. It is shown that thermodynamic stability of Titanium was enhanced which means that corrosion tendency was decreased. Furthermore corrosion rate was decreased more than eight times. The most important achievement of this study is improvement of the resistance against pitting corrosion.