β irradiation in borosilicate glasses: the role of the mixed alkali effect

Ollier, Nadège; Boizot, Bruno; Reynard, Bruno; Ghaleb, D.; Petite, G.

doi:10.1016/j.nimb.2003.12.014

Cited by 52 publications

(49 citation statements)

References 20 publications

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“…These phenomena also take place in glasses irradiated by electrons where they are initiated by the formation of point defects [27,28]. These composition dependent defects can further lead to the release of charge compensators that can enable alkali migration and formation of alkali clusters [28], as well as the creation of molecular oxygen [29] following either β or x-ray irradiation [30,31]. Alkali migration and clustering can foster the creation of a precursor environment for molybdate formation; hence, it is a factor governing precipitation during long-term storage.…”

Section: Introductionmentioning

confidence: 99%

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

Patel

Boizot

Facq

et al. 2017

Journal of Non-Crystalline Solids

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A B S T R A C TBorosilicate glasses for nuclear waste applications are limited in waste loading by the precipitation of watersoluble molybdates. In order to increase storage efficiency, new compositions are sought out that trap molybdenum in a water-durable CaMoO 4 crystalline phase. Factors affecting CaMoO 4 combination and glass-inglass phase separation in calcium borosilicate systems as a function of changing [MoO 3 ] and [B 2 O 3 ] are examined in this study in order to understand how competition for charge balancers affects phase separation. It further examines the influence of radiation damage on structural modifications using 0.77 to 1.34 GGy of 2.5 MeV electron radiation that replicates inelastic collisions predicted to occur over long-term storage. The resulting microstructure of separated phases and the defect structure were analyzed using electron microscopy, XRD, Raman and EPR spectroscopy prior to and post irradiation. Synthesized calcium borosilicates are observed to form an unusual heterogeneous microstructure composed of three embedded amorphous phases with a solubility limit~2.5 mol% MoO 3. Increasing [B 2 O 3 ] increased the areas of immiscibility and order of (MoO 4 ) 2 − anions, while increasing [MoO 3 ] increased both the phase separation and crystallization temperature resulting in phases closer to metastable equilibrium, and initiated clustered crystallization for [MoO 3 ] > 2.5 mol%. β-irradiation was found to have favorable properties in amorphous systems by creating structural disorder and defect assisted ion migration that thus prevented crystallization. It also increased reticulation in the borosilicate network through 6-membered boroxyl ring and Si ring cleavage to form smaller rings and isolated units. This occurred alongside an increased reduction of Mo 6 + with dose that can be correlated to molybdenum solubility.In compositions with existing CaMoO 4 crystallites, radiation caused a scattering effect, though the crystal content remained unchanged. Therefore β-irradiation can preferentially prevent crystallization in calcium borosilicates for [MoO 3 ] < 2.5 mol%, but has a smaller impact on systems with existing CaMoO 4 crystallites.

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Section: Introductionmentioning

confidence: 99%

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

Patel

Boizot

Facq

et al. 2017

Journal of Non-Crystalline Solids

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“…The latter is of particular interest as it is commonly used as a simplified model of high level waste confinement matrix. Irradiation effects on this glass are currently investigated, especially the role of the mixed alkali effect on ion diffusion under irradiation [13]. Raman spectroscopy is a powerful tool to characterize borosilicate glasses structure [14][15][16][17] but it cannot give quantitative information about the polymerization degree or the boron speciation.…”

Section: Introductionmentioning

confidence: 99%

A Raman and MAS NMR study of mixed alkali Na–K and Na–Li aluminoborosilicate glasses

Ollier

Charpentier

Boizot

et al. 2004

Journal of Non-Crystalline Solids

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“…However, in sample #7 there are three ESR signals corresponding to the g values 1.96 ± 0.02, 2.06 ± 0.02 and 2.18 ± 0.02. The ESR signal at 2.06 and 2.18 are due to oxygen hole centers [26][27][28]. These results indicate that the nature of defects and their formation rate depend on the glass matrix composition.…”

Section: Esr Spectramentioning

confidence: 76%

Persistent spectral hole burning studies in europium doped sodium silicate and borosilicate glasses

Kalluru

Pulluru

Bairavarasu

et al. 2006

Journal of Non-Crystalline Solids

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β irradiation in borosilicate glasses: the role of the mixed alkali effect

Cited by 52 publications

References 20 publications

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

A Raman and MAS NMR study of mixed alkali Na–K and Na–Li aluminoborosilicate glasses

Persistent spectral hole burning studies in europium doped sodium silicate and borosilicate glasses

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