Oxidation of ion-bombarded vs. annealed beryllium

The mechanisms of O2 adsorption and oxidation of ion-bombarded and annealed highly oriented polycrystalline beryllium surfaces were comparatively studied. It was found out that the basic mechanism of oxygen adsorption involves O clusters for both surfaces and at a certain oxygen coverage nucleation and growth of oxide islands take place. Also, in both cases, lateral growth of the islands dictates a relatively fast oxidation rate, which is decreased following coalescence, turning to a slow inverse logarithmic growth. troduction of surface and subsurface defects by the Ar+ ion-bombardment almost doubles the oxygen sticking coefficient, increases the oxide island thickness from ∼2 to ∼3 monolayers (prior to coalescence) and dictates a higher oxidation rate in the high oxygen exposure regime. also found that annealing the surface, following sputtering, causes its smoothing, but in the initial heating process, in the range 300–500 K coarsening seems to occur.