Influence of Fe³⁺ on Corrosion Behavior of TC4 in Sulphuric Acid Solutions

The corrosion behaviour of titanium alloy TC4 in 44.6% sulphuric acid solutions with various concentrations of Fe3+, was studied by immersion tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results showed that when the concentration of Fe3+ reached 0.005 mol/L in 44.6% sulphuric acid solution, the corrosion rate of TC4 droped from 1.0 × 103 μm/a to 1.0 μm/a.The cathodic process of the corrosion reaction was suppressed, the corrosion potential shifted to positive, and the corrosion resistance of TC4 was enhanced obviously.