Oxygen adsorption on the Co50Ni50(111) surface

Abstract Oxygen adsorption on the Co 50 Ni 50 (111) surface at RT has been studied by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The uptake rate and the work function variations show the different stages of linear initial adsorption, oxide nucleation and oxide thickening. Chemisorption of oxygen induced a segregation of cobalt. Heating at 327°C caused a further cobalt segregation which reduced Ni 2+ to Ni 0 and finally islands of cobalt oxide were formed.