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

Bach, H.; Venhaus, Thomas J.; Paglieri, Stephen N.; Oona, H.; Allen, Thomas H.; Schwarz, R. B.; Wermer, Joseph R.

doi:10.1016/j.jallcom.2007.01.037

Cited by 13 publications

(6 citation statements)

References 17 publications

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“…Ce is easily reacts with hydrogen to form Ce hydride. It seemed that the formation of Ce hydride could increase the hydrogen capacity and improve the activation kinetics of Ti-V based alloy on the first hydrogen absorption process [12], but on the subsequent hydrogen sorption process, Ce hydride becomes the dead phase and has no any contribution to the hydrogen capacity due to its low equilibrium desorption pressure (about 1 Pa at 773 K [13]). …”

Section: Resultsmentioning

confidence: 99%

Improve plateau property of Ti32Cr46V22 BCC alloy with heat treatment and Ce additive

Liu

Jiang

et al. 2009

Journal of Alloys and Compounds

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Section: Resultsmentioning

confidence: 99%

Improve plateau property of Ti32Cr46V22 BCC alloy with heat treatment and Ce additive

Liu

Jiang

et al. 2009

Journal of Alloys and Compounds

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“…The subsequent growth rate of sample C was about half of that of sample B, as indicated by the slope parameter in Table . The longer induction period induced by the oxide layer had been widely reported, , but the relevant mechanism was still unclear. In this experiment, we did not consider the effects of pollutants such as hydroxylation and water, most of which were removed by the preheating process.…”

Section: Discussionmentioning

confidence: 99%

“…The H concentration is governed by the net difference between the abundance of incoming H atoms passing the SPL and the abundance of outgoing H atoms diffusing into the metal. The duration of H build-up to the terminal solid solution of hydrogen, the induction period, , is affected by several factors such as oxide thickness, oxide heterogeneity, degree of surface hydroxylation, and the abundance of impurity phase in the metal . These factors are believed to modify the sequences of elementary partial steps of the induction period. , First, the surface sorption step involves physisorption of H 2 at the oxide surface.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it is important to experimentally determine the role of each step in the theoretical prediction. For example, the oxide layers were reported to strongly affect the kinetics in the initial stages of hydrogen–metal reactions. , Both the surface sorption and permeation are speculated to restrict the hydrogen–metal reactions, , but their actual contributions in the initial nucleation process have not been experimentally verified. However, it is still difficult to experimentally clarify the regulating step/steps in initial hydrogen reactions because the steps mentioned above occur sequentially and interact with each other during the hydriding process of the oxide-coated metal.…”

Section: Introductionmentioning

confidence: 99%

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In Situ Small-Angle Neutron Scattering Analysis of the Initial Deuteride Formation of Deuterium–Cerium Reactions under a Controlled Gas Flow

et al. 2020

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Metrics & MoreArticle RecommendationsABSTRACT: "Real-life" metals inevitably form the oxide layer, thus leading to complex initial hydriding processes, which are still unclear because of the experimental challenges in monitoring elemental steps including surface sorption, permeation, and concentration of hydrogen. In this study, the deuteride precipitation caused by the concentration of deuterium was successfully measured by the in situ small-angle neutron scattering (SANS) method, which used a selfdesigned reaction chamber to give rise to the scattering signals of the surface structure. In addition, in the measurements of activated cerium samples, surface sorption of deuterium could be modified to form a constant flow in order to further explore the initial hydriding processes. The formation of deuterides was found to occur as soon as deuterium was absorbed in the samples with a thin oxide layer and the subsequent growth of deuterides depended on the amount of consumed D 2 . However, the sample with a thick oxide layer showed the delayed precipitation of deuterides and the decelerated subsequent growth of deuterides without inhibiting the surface absorption of deuterium. The in situ SANS method showed the high sensitivity to the deuteride phase on the surface at a deuterium amount of 0.2 μmol cm −2 D 2 for cerium and a great potential in exploring the mechanism of early incipient stages of hydrogen reactions.

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“…Recently, vacuum annealing has been shown to promote the surface reactivity of some rare earth metals towards hydrogen adsorption owing to the desorption of surface contaminants and modifications to the oxide over-layer [5][6][7], therefore, a similar enhanced surface reactivity with uranium could be expected [8].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

et al. 2012

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The reaction kinetics of depleted uranium under constant hydrogen pressure (1 bar) have been measured as a function of reaction temperatures between 65 and 385 °C for as-polished and vacuum annealed samples. Enhanced hydrogen reactivity was observed on samples that underwent vacuum annealing prior to hydrogen exposure. The enhanced reactivity was found to be the result of enhanced nucleation rates on annealed samples since the specific rate per reacting unit area remained unaffected. X-ray photoelectron spectroscopy demonstrates that the nucleation kinetics were promoted on annealed samples as a result of the dehydration and partial reduction of the UO 2+x outer oxide layer and the formation of an oxycarbide (UO x C y ) sub-layer.

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

Cited by 13 publications

References 17 publications

Improve plateau property of Ti32Cr46V22 BCC alloy with heat treatment and Ce additive

Improve plateau property of Ti32Cr46V22 BCC alloy with heat treatment and Ce additive

In Situ Small-Angle Neutron Scattering Analysis of the Initial Deuteride Formation of Deuterium–Cerium Reactions under a Controlled Gas Flow

The Influence of Vacuum Annealing on the Nucleation and Growth Kinetics of Uranium Hydride

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