The incipient kinetics of hydride growth on cerium surfaces

The strain energy and shape evolution of hydrides precipitated at free surfaces of metals

“…5c). This phenomenon may be important during the growth of hydrides [3][4][5][6] and it deserves further study.…”

“…Multiple hemispherical hydrides nucleate, sometime preferably along slip lines. Most of them cease to grow but a few grow into large precipitates [4][5][6]. Bloch et al [3] suggested that the increase in elastic energy accumulated during the growth process causes the interception of the growth.…”

UD3formation on uranium: evidence for grain boundary precipitation

“…The initial development of hydrides on metallic surfaces is observed to occur in isolated zones or 'spots' [6], [10], [11], [12], [13], [14], indicating that certain areas favour the onset of hydride forming reactions. It follows that these zones experience shorter induction times than elsewhere on the sample surface, which may be attributed to the effects of defects or cracks in the oxide layer, localised thinning, regions of enhanced hydrogen species permeability or regions of enhanced hydrogen surface dissociation (although the exact nature of the hydrogen species which transport through the surface oxide film is currently unknown) [15].…”

The effect of surface state on the kinetics of cerium-hydride formation

“…The bulk Ce sample clearly has faster H absorption kinetics than the foil. The Ce hydriding reaction consists of four distinct stages: (a) initial rapid uptake of a small amount of H, (b) an induction stage, (c) a nucleation and bulk reaction stage characterized by steadily increasing and then linear uptake, and (d) a period during the end of absorption where the reaction slows down considerably [3,6]. The small initial uptake of H by the Ce bulk seen in the inset in Fig.…”