Stability and Structural Evolution of CeIV1–xLnIIIxO2–x/2 Solid Solutions: A Coupled μ-Raman/XRD Approach

Horlait, Denis; Claparède, Laurent; Clavier, Nicolas; Szenknect, Stéphanie; Dacheux, Nicolas; Ravaux, Johann; Podor, Renaud

doi:10.1021/ic200751m

Cited by 112 publications

(129 citation statements)

References 77 publications

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“…The evolution of the cell parameter refined from the X-ray diffraction patterns is in good agreement with data given in the literature [22,23,25] (Table 4, Fig. 8) and with the results from the precipitate.…”

Section: Precipitates Calcinationsupporting

confidence: 89%

“…There is no diffusion at 1250°C between the mixed oxide Ce 1Ày Nd y O 2À0.5y coming from precipitation and the mixed oxide Ce 1Àx Nd x O 2À0.5x coming from oxychloride conversion. The cerium/neodymium mixed oxides have been previously investigated by several authors [22][23][24][25]. With the increase of neodymium concentration, the mixed oxide structure changes from fluorine F-type (Fm 3 m, with a F unit cell parameter) to the superstructure C-type (Ia 3, a C % 2a F unit cell parameter) at about x Nd -% 0.40.…”

Section: Precipitates Calcinationmentioning

confidence: 99%

See 1 more Smart Citation

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

Vigier

Renard²,

Laplace³

et al. 2013

Journal of Nuclear Materials

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Section: Precipitates Calcinationsupporting

confidence: 89%

Section: Precipitates Calcinationmentioning

confidence: 99%

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

Vigier

Renard²,

Laplace³

et al. 2013

Journal of Nuclear Materials

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“…For all the chemical compositions considered, the PXRD patterns collected ( Fig. 1) exhibited wide XRD lines (large FWHM) that fit with the cubic fluorite-type structure (Fm-3m space group), characteristic of both CeO 2 [27] and actinide dioxides [28]. From these data, the precipitation of a partly amorphous hydrated oxide was found to be the most credible hypothesis, albeit the formation of such compound could also occur through the aging of an initial hydroxide form, for example during the drying procedure, considering the following reaction:…”

Section: Characterization Of the Precursorsmentioning

confidence: 92%

An original precipitation route toward the preparation and the sintering of highly reactive uranium cerium dioxide powders

Martinez

Clavier

Mesbah

et al. 2015

Journal of Nuclear Materials

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h i g h l i g h t sDense (U,Ce)O 2 pellets were prepared from highly reactive precursors. Nanosized hydrated oxides were first obtained through precipitation route. Direct sintering was performed by heating between 1350°C and 1550°C. Microstructures composed of dense materials with submicrometric grains were achieved. a b s t r a c tThe preparation of dense U 1Àx Ce x O 2 mixed dioxides pellets was achieved from the initial precipitation of highly reactive precursors. In a first step, a wet chemistry route, based on the mixture of U 4+ and Ce 4+ in acidic solution with large excess of NH 4 OH, was set up to reach the precipitation of the cations. The solid phase was then dried under vacuum to avoid aggregation phenomena. Further characterization of the powders by XRD, EDS and TEM revealed the formation of hydrated U 1Àx Ce x O 2 ÁnH 2 O that probably resulted from the aging of hydroxide compounds. Also, microscopy investigations evidenced the nanosized character of the powder which was associated to high values of specific surface area, typically in the 100-150 m 2 g À1 range.The behavior of U 1Àx Ce x O 2 ÁnH 2 O versus temperature was investigated in a second part. If the increase of the heat temperature allowed one to observe an improvement of the crystallization state linked with the growth of crystallites, it was also accompanied by a strong decrease of the powders reactivity. On this basis, sintering tests were conducted in reducing atmosphere on the compounds as prepared. Dilatometry experiments indicated a low densification temperature compared to other ways of preparation reported in the literature. Also, the pellets prepared after firing at different temperatures (1350-1550°C) showed that a wide range of microstructures was achievable. Particularly, bulk materials with densities of 90-95% of the calculated value could be prepared with average grain size ranging from around 100 nm to more than 5 lm. This simple process of elaboration of dense materials from highly reactive hydrated oxide precursor thus appears as a very interesting way to prepare actinide oxides materials.

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“…For both series, the patterns exhibited all the PXRD lines of the fluorite-type structure (cubic, Fm-3m space group) which is characteristic of ThO 2 [26] and CeO 2 [12] compounds. The synthesis process then did not end up with the formation of Th-or Ce-based hydroxides but with the precipitation of hydrated oxides.…”

Section: Characterizationo Ft He Powdered Samplesmentioning

confidence: 96%

Synthesis and Direct Sintering of Nanosized (M^IV,M^III)O_2‐x Hydrated Oxides as Electrolyte Ceramics

et al. 2017

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Highly reactive and nanosized Th1‐xYxO2‐x/2 or Ce0.8Ln0.2O1.9 mixed oxides were prepared through the initial precipitation of hydroxide precursors which were further dried under vacuum. Whatever the chemical system investigated, the characterization of the powdered samples evidenced a rapid aging process leading to hydrated oxides. The thermal behavior of these samples was further investigated and first showed a two‐step dehydration process, with the successive departure of adsorbed and constitutive water, both yielding a drastic drop of the powders’ reactivity (i.e. decrease of the specific surface area). Sintering experiments were then undertaken by starting directly from raw powders and revealed very rapid densification kinetics. Highly densified pellets (above 95 %TD) with a fine grain microstructure were obtained after only 1 hour of heat treatment at 1600 °C. This easy and versatile process of precipitation, that can be followed by direct densification of the powders, then appears as a promising option for the elaboration of homogenous ceramic electrolytes.

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Stability and Structural Evolution of Ce^IV_1–xLn^III_xO_2–x/2 Solid Solutions: A Coupled μ-Raman/XRD Approach

Cited by 112 publications

References 77 publications

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

An original precipitation route toward the preparation and the sintering of highly reactive uranium cerium dioxide powders

Synthesis and Direct Sintering of Nanosized (M^IV,M^III)O_2‐x Hydrated Oxides as Electrolyte Ceramics

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Stability and Structural Evolution of CeIV1–xLnIIIxO2–x/2 Solid Solutions: A Coupled μ-Raman/XRD Approach

Cited by 112 publications

References 77 publications

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

An original precipitation route toward the preparation and the sintering of highly reactive uranium cerium dioxide powders

Synthesis and Direct Sintering of Nanosized (MIV,MIII)O2‐x Hydrated Oxides as Electrolyte Ceramics

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Product

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Stability and Structural Evolution of Ce^IV_1–xLn^III_xO_2–x/2 Solid Solutions: A Coupled μ-Raman/XRD Approach

Synthesis and Direct Sintering of Nanosized (M^IV,M^III)O_2‐x Hydrated Oxides as Electrolyte Ceramics