A comparative study on the corrosion of pure titanium and titanium–12%zirconium alloy after different exposure periods of time in sodium chloride solution

Abstract

In this work, the powder metallurgy technique was employed to manufacture pure titanium (Ti) and 88% titanium–12% zirconium (TiZr) alloy. The electrochemical corrosion investigations for pure Ti and the TiZr alloy were carried out after exposure for 30 min and 3 days in 3.5% NaCl solutions. The Nyquist and Bode plots obtained from the electrochemical impedance spectroscopy experiments revealed that the presence of Zr remarkably magnifies the corrosion resistance of Ti via increasing the impedance and degree of the phase angle, as well as the polarization and solution resistances. The potentiodynamic cyclic polarization measurements revealed that the presence of 12% Zr highly enhances the corrosion resistance of Ti. These polarization results showed that Zr addition reduces the corrosion of Ti via decreasing its corrosion rate. The intensity of the current when measured with increasing time of the experiment at −0.10 mV (Ag/AgCl) indicated that the addition of 12% Zr greatly decreases the absolute current, which indicates that alloying Zr within Ti reduces the severity of its corrosion in the chloride electrolyte. The morphology of the surfaces and the possible surface layer(s) for the corroded Ti and TiZr samples were analyzed using a scanning electron microscope and energy dispersive x rays. Results collectively depicted that the presence of Zr increases the corrosion resistance when alloyed with Ti.