Corrosion Behavior of Commercial Pure Titanium in Alkali Containing Chloride Ion

The corrosion mass gain, corrosion morphology and electrochemical characteristics of commercial pure titanium TA2 in 1 mol/L NaOH solution with different Cl^- concentrations (0.01, 0.10 and 1.00 mol/L) were studied by means of weight gain method, optical microscopy, potentiodynamic polarization curves, electrochemical impendance spectra and Mott-Schottky curves. And the effect of Cl^- concentration on the corrosion behavior of the TA2 was analyzed. The results indicate that the TA2 had excellent corrosion resistance in NaOH solution containing Cl^-. With the increase of Cl^- concentration, corrosion potential decreased, while both the current density and the passive current density increased, which indicated the corrosion resistance of the TA2 decreased. When the concentration of Cl^- increased, the hydrogen evolution reaction on cathode had little effect, while the cathode oxygen absorption corrosion current density first increased and then decreased. The passive film on the surface of TA2 was n-type semiconductor, which had strong corrosion resistance to Cl^-.