SIMS AND AUGER INVESTIGATION OF OXYGEN-ADSORPTION ON POLYCRYSTALLINE NICKEL SURFACE

As it is known, the secondary ion yields increase stepwise upon increa sing O2 exposure, during SIMS measurements on metal samples in an oxyg en atmosphere. Taking Auger spectra at varying oxygen exposure, the va riation of satellite peaks and the chemical shift has been monitored, and a similar step-like dependence at the same range of oxygen exposur es was found. This shows, that the discontinuous increase in the secon dary ion intensity is due to the different types of oxides formed on t he metal surface. Identification of these oxides are discussed.