The influence of Ar+ sputtering on the hydriding behavior of uranium

The influence of superficial defects (induced by surface sputtering) on uranium oxidation and hydriding behaviors has been studied. Depleted uranium surface was etched by Ar+ sputtering, the etched surface morphology was investigated by scanning electron microscope. The initial oxidation kinetics of sputtered uranium surface and mechanical polished uranium surface in ambient atmosphere were characterized using spectroscopic ellipsometry. As-polished and sputtered samples, as well as sequence sputtered samples ambient oxidized for different time, were compared in hydriding kinetics to investigate the co-influence of surface oxidation and superficial defects induced by Ar+ ion bombardment. The morphologic characteristics of hydride sites in a few grains were also revealed and enhanced by sputtering, showing a network of fractures for fast hydride transportation.