Corrosion behavior of plasma electrolytically oxidized gamma titanium aluminide alloy in simulated body fluid

• Dense PEO coatings with submicron pores can be formed on γTiAl.
• The corrosion resistance of PEO treated γTiAl is considerably higher.
• The PEO treatment also reduces localized corrosion to a great degree.

Plasma electrolytic oxidized (PEO) γTiAl alloy samples were electrochemically characterized by open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) to evaluate their corrosion resistance in simulated body fluid (SBF) in order to gauge their potential for biomedical applications. Experimental results through OCP and cyclic polarization studies demonstrated the protective nature and the beneficial effect of the PEO coatings on γTiAl. The PEO surface increased corrosion resistance of these surface modified alloys. EIS data indicated the presence of an underlying compact oxide layer with surface pores represented by two domes in the Nyquist plots. Electrical equivalent circuits to describe the EIS results are proposed.