The transformation balance between two types of structural defects in silica glass in ion-irradiation processes

Yang, Tonghai; Gao, Yuan; Huang, Xuejun; Zhang, Yongfeng; Toulemonde, M.; Xue, Jianming; Wang, Yugang

doi:10.1016/j.jnoncrysol.2011.05.017

Cited by 18 publications

(10 citation statements)

References 45 publications

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“…This may indicate that a larger scale local damage, as compared to simple O vacancies or NBOHCs, is needed to create divalent Si in quartz. This conclusion is in accord with the observations that SiODC(II) is most efficiently created by types of irradiation, which cause a massive lo-calized damage (amorphization, nanovoids): ion beam [41], fs-laser writing [42,43], and is not created by "soft" (e.g., γor electron) irra-diation [5,6], capable of displacing only single oxygen atoms.…”

Section: Divalent Si -Odc(ii)supporting

confidence: 89%

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

Skuja

Ollier

Kajihara

et al. 2019

Journal of Non-Crystalline Solids

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Point defects in crystalline SiO2, created by 2.5 MeV electron irradiation at dose below the amorphization threshold or by fast neutrons, were compared by luminescence spectroscopy. Oxygen dangling bonds ("non-bridging oxygen hole centers", NBOHCs), peculiar to amorphous state of SiO2, were detected for the first time in electron-irradiated non-amorphized αquartz crystal. Their presence may signal the formation of nucleation centers in crystal structure as the first step to radiationinduced amorphization. Compared to crystal, irradiated by 10 19 cm −2 fast neutrons, their concentration was over 100 times lower, and their inhomogeneous broadening was at least 2.5 times smaller. Divalent silicons ("silicon oxygen deficiency centers", SiODC(II)), inherent to oxygen-deficient or irradiated SiO2 glass, were detected in neutron-irradiated (10 19 n/cm 2) α-quartz but were not found after the electron irradiation. Radiation-induced interstitial O2 molecules, characteristic to irradiated glassy SiO2 and other oxide glasses, are found in α-quartz only after neutron irradiation. The oxygen atoms, displaced by the 2.5 MeV e − irradiation of α-quartz for fluences up to 10 19 e − /cm 2 evidently stays entirely in the peroxy linkage (Si-O-O-Si bond) form.

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Section: Divalent Si -Odc(ii)supporting

confidence: 89%

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

Skuja

Ollier

Kajihara

et al. 2019

Journal of Non-Crystalline Solids

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“…Yang et al hypothesized that Au irradiation caused cleavage of sixmembered Si rings that subsequently resulted in the formation of two E′ and NBHOC (non-bringing oxygen hole center) defects. The resulting fragments could then be recombined to form smaller rings, thus resulting in growth of the Raman defect bands D 1 and D 2 [69]. As β-irradiation also causes growth in these Raman modes, we can predict that the same structural modifications are taking place following electronic energy deposition.…”

Section: Radiation Effectsmentioning

confidence: 97%

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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“…The creation of structural disorder following irradiation damage extends to the borosilicate network according to Raman analysis, which showed the creation of smaller or distorted ring structures through the emergence of the D 1 and D 2 defect bands. This observation implies a process of defectassisted breaking of large rings and reformation of smaller ones, often with a single type of network former, as has been previously hypothesized to occur [47,75]. This process of ring cleavage is predicted to increase the dissolution of MoO 4 2entities by creating more diffusion pathways and by altering the order and size of depolymerized areas within the glass structure.…”

Section: Phase Separation In the Borosilicate Network Following Irradmentioning

confidence: 63%

Swift heavy ion-irradiated multi-phase calcium borosilicates: implications to molybdenum incorporation, microstructure, and network topology

et al. 2019

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A series of calcium borosilicate glasses with varying [B 2 O 3 ], [MoO 3 ], and [CaO] were prepared and subjected to 92 MeV Xe ions used to simulate the damage from long-term a-decay in nuclear waste glasses. Modifications to the solubility of molybdenum, the microstructure of separated phases, and the Si-O-B network topology were investigated following five irradiation experiments that achieved doses between 5 9 10 12 and 1.8 9 10 14 Xe ions/cm 2 in order to test the hypotheses of whether irradiation would induce, propagate, or anneal phase separation. Using electron microscopy, EDS analysis, Raman spectroscopy, and XRD, irradiation was observed to increase the integration of MoO 4 2by increasing the structural disorder within and between heterogeneous amorphous phases. This occurred through Si/B-O-Si/B bond breakage and reformation of boroxyl and 3/4-membered SiO 4 rings. De-mixing of the Si-O-B network concurrently enabled cross directional Ca and Mo diffusion along defect created pathways, which were prevalent along the interface between phases. The initiation and extent of these changes was dependent primarily on the [SiO 2 ]/[B 2 O 3 ] ratio, with [MoO 3] having a secondary effect on influencing the defect population with increasing dose. Microstructurally, these changes to bonding caused a reduction in heterogeneities between amorphous phases by reducing the size and increasing the spatial distribution of immiscible droplets. This general increase in structural disorder prevented crystallization in most cases, but where precipitation was initiated by radiation, it was re-amorphized with increasing dose. These outcomes suggest that internal radiation can alter phase separation tie lines, and can therefore be used as a tool to design certain structural environments for long-term encapsulation of radioisotopes.

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The transformation balance between two types of structural defects in silica glass in ion-irradiation processes

Cited by 18 publications

References 45 publications

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

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

Swift heavy ion-irradiated multi-phase calcium borosilicates: implications to molybdenum incorporation, microstructure, and network topology

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The transformation balance between two types of structural defects in silica glass in ion-irradiation processes

Cited by 18 publications

References 45 publications

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

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

Swift heavy ion-irradiated multi-phase calcium borosilicates: implications to molybdenum incorporation, microstructure, and network topology

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Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons

Creation of glass-characteristic point defects in crystalline SiO2 by 2.5 MeV electrons and by fast neutrons