Chemical effects induced in alkali Phosphates by 2 keV Ar ion bombardment

Abstract

Various alkali phosphates have been bombarded with 2 keV Ar ions at doses ranging between 10¹⁵ and 4 × 10¹⁶ ions/cm². The modifications induced at the surfaces have been followed by ESCA. Both stoichiometric and valence structure modifications are induced by the bombardment on the phosphate surfaces. The ESCA spectra indicate that the residual surfaces have been in part transformed into polyphosphate-like compounds. The main parameter which determined the condensation degree has been found to be the (oxygen/ metal) ratio. The results are interpreted in terms of a recently proposed model which links the primary physical processes, mainly considered to be binary colisions between the projectile and the target atoms, to the subsequent chemical reactions.