Electronic States Of Cathodes Of Ti-Based Alloys In Aqueous Corrosion

In order to understand cathodic reactions of Ti-based alloys, the localized electronic states of a cathode were simulated by the DV-X-alpha cluster method. The results were interpreted on the basis of an electron theory.A local electronic cell is considered here. The anode is the titanium-matrix region and the cathode is the alloying-element containing region. It is likely that the cathodic reaction is enhanced strongly when many conduction electrons localize in the cathode, and then thses electrons discharge to H+ smoothly and forming H-2 on the cathode. The tendency of electron localization can be evaluated by the number of electron vacancies on the Fermi level. On the other hand, the tendency of discharging electron to H+ appears to be associated with the height of Fermi level.It was found that the cathode containing Ir, Pt, Rh, Pd and Ni had more electron vacancies and exhibited a higher Fermi level than the cathode containing other elements, and enhanced a cathodic reaction. However, these changes of electronic states on the Fermi level of the cathode occurred mainly in electron configurations of Ti atoms which were affected by the presence of alloying elements.