The polarization behavior of titanium in hydrochloric acid has been investigated. Titanium in 4N HCl showed an active and passive region during anodic polarization. After anodic polarization into the passive region, titanium remained passive but could be reactivated by cathodic polarization. Cathodic polarization of titanium showed a Tafel region for the hydrogen evolution reaction. The differential capacitance at the active corrosion potential was 152 μf/cm , and at the passive corrosion potential the capacitance was 24 μf/cm2. A maximum in the capacitance, 350 μf/cm2, was observed at -0.470 mV (SCE) which was the primary passivation potential. A minimum in the capacitance, 76 μf/cm2, occurred at -0.855 ±15 mV (SCE). A comparison of electrochemical parameters of titanium in HCl and H2SO4 at the same pH indicates that the anodic dissolution of titanium in HCl is less than in H2SO4.

Subject
Cathodic polarization, Electric current, Active corrosion, Sulfuric acid, Chloride ions, Capacitance, Passivation, Titanium, Polarization, Anodic polarization, Electrodes, Corrosion potential, Electrode potential
© 1973 National Association of Corrosion Engineers
1973
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