Processes associated with the Pd + D alloy codeposition are examined by cyclic voltammetry. The voltammograms cover the potential range : +0.3 to -1.3 V (measured against an Ag/AgCl/KCl (sat) reference) and indicate that the partial current due to the Pd2+ ion reduction is diffusion limited at slow scan rates. Except for the significant increase in cathodic currents due to D2O reduction at ca. -0.25 V which occurs on a freshly generated Pd surface, the shapes of the voltammograms marginally differ from those recorded in the absence of Pd2+ ions in the electrolyte phase. A discussion of the dynamics of the interphase is presented.