Model of oxide layer growth on Ag super(+) and Pt super(+) ion implanted nickel anode in aqueous alkaline solution

This work investigates nickel oxide films growth on nickel implanted with ions of the noble metals Ag and Pt. Polycrystalline and single crystal samples of Ni were implanted with high fluences (1x10 super(19)-1x10 super(21) m super(-2)) of 9-50 keV ions. Galvanostatic and potentiostatic polarization techniques were applied to monitor the electrochemical efficiencies of formation of Ni sub(X)O sub(1-X) films in aqueous KOH solution (30%) at 353 K. The growth rates, thickness and compositional profiles of oxidized nickel layers were examined by means of RBS. It was found that the anodic oxide film consists of Ni(OH) sub(2)X H sub(2)O (X greater than or equal to 1). Anodic oxidation of nickel occurs due to out-diffusion of Ni atoms through the hydroxide layer. Implanted Ag penetrates partly into the anodic oxide whereas platinum is completely buried beneath the oxide film.