Characterization of Ar+-ion irradiated alumina coatings

Characterization of plasma-sprayed alumina coatings before and after Ar+-ion irradiation was performed by XPS and ESR techniques. Two Osub(1s) peaks were observed in all Ar+-ion irradiated alumina coatings. The Osub(1s) peaks with 4 - 5 eV higher energy than Osub(1s) binding energy in normal α-Al2O3 are assigned of nearly monovalent oxygen ions. Aluminum ions with higher partial charge than one in normal α-Al2O3 are attributed to the association of nearly monovalent oxygen ions to aluminum ions. Two resonances were observed near 340 mT and 341 mT, respectively. The resonance near 340 mT may be originated from hole-trapped (that is, nearly monovalent) oxygen ions. Further, the formation of an amorphous layer was suggested at the dose of 1016 and 1017 Ar+/cm2. (orig.)