Oxygen non-stoichiometries in (Th0.7Ce0.3)O2−x

Osaka, Masahiko; Miwa, Shuhei; Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinşuke

doi:10.1016/j.jnucmat.2010.11.065

Cited by 3 publications

(2 citation statements)

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“…The first probable hypothesis could result from the partial reduction of Ce(IV) to Ce(III), at the extreme surface of the sample, during the heating treatment itself leading to the preferential release of this latter during dissolution tests. This reduction was already mentioned in the literature even though it was found to be lower for Th 1– x Ce x O 2 solid solutions than for CeO 2– x …”

Section: Resultssupporting

confidence: 57%

“…This reduction was already mentioned in the literature even though it was found to be lower for Th 1Àx Ce x O 2 solid solutions than for CeO 2Àx . 72 • Also, one could also argue that this effect may be due to the additional specific reduction of Ce(IV) to Ce(III) at the solid/liquid interface during the leaching tests. Indeed, despite the high value of the standard potential of Ce IV / Ce III in solution (E 0 (Ce IV /Ce III ) = 1.44 V/NHE), such reaction could be induced by nitrous acid (HNO 2 , E 0 ≈ 1 V/NHE) formed trough the HNO 3 instability in such experimental conditions (high acid concentrations and T = 60 °C).…”

Section: Dissolution Of Th 1àx Cementioning

confidence: 99%

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Multiparametric Dissolution of Thorium–Cerium Dioxide Solid Solutions

et al. 2011

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The dissolution of Th(1-x)Ce(x)O(2) solid solutions samples prepared by thermal conversion of oxalate precursors was studied by varying independently several parameters (such as chemical composition, leachate acidity, leaching temperature, firing temperature, and crystallization state). The relative effects of these parameters on the normalized dissolution rate were examined. Either the obtained partial order related to the proton activity (n = 0.50 ± 0.01) or the activation energy (E(A) = 57 ± 6 kJ.mol(-1)) suggested that the dissolution was mainly driven by surface reactions occurring at the solid/liquid interface. Conversely to that observed for Th(1-x)U(x)O(2) and Ce(1-x)Nd(x)O(2-x/2) solid solutions, the chemical composition did not induce strong modifications of the chemical durability of the leached samples. While the initial normalized dissolution rate slightly depended on the elimination of crystal defects for firing temperatures below 800 °C, it was mainly independent of the crystallite size (T ≥ 900 °C). The role of crystal defects (then that of preparation conditions) appeared thus important to consider since they contributed to modifications of the normalized dissolution rates of the same order of magnitude than that of the leachate acidity.

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Section: Resultssupporting

confidence: 57%

Section: Dissolution Of Th 1àx Cementioning

confidence: 99%