X-RAY PHOTOEMISSION SPECTROSCOPY (XPS) ANALYSIS OF FE82B18-AL2O3 GRANULAR SYSTEMS

X-ray photoemission spectroscopy (XPS) has been used to investigate the surface composition (down to some hundreds of Å) of granulars consisting of Fe82B18 small particles (?~40-70 Å) dispersed in an alumina insulating matrix. Fully oxidized iron and boron are found in the outermost region of samples while in depth analysis, achieved by Ar+ ion etching, provides evidence of both metallic and oxidized states for the two elements. Aluminate forms, suggestive of an interaction at the surface of the alloy particle and alumina, are also present in the sub-surface region and the interaction extent is quantitatively evaluated as a function of the particle size.