Effect of the Hydride Layer on the Anodic Polarization Behavior of Titanium in Sulfuric Acid

Abstract

It was found that the anodic polarization behavior of titanium in sulfuric acid solution is affected by the presence of titanium hydride layer formed on the surface by the corrosion reaction. When the hydride was present, a new peak appeared in the anodic polarization curve at the potentials of -0.1-0V vs. S. C. E. The height of this peak increased with the increase of the amount of hydride formed on the surface prior to the polarization measurement. The more the amount of hydride was and the higher the peak was, the more time was required to activate titanium after the anodic passivation. Since the starting potential of the peak was slightly more noble than the hydrogen redox potential of the sulfuric acid solution used, the new peak was attributed to the oxidation reaction of hydrogen absorbed in or reacted with titanium. The hydrogenation of titanium by the cathodic polarization in sodium sulfate solution gave the same effect on the anodic polarization curve in sulfuric acid.