Oxide glass structure evolution under swift heavy ion irradiation

https://doi.org/10.1016/j.nimb.2014.02.002Get rights and content

Highlights

  • Structure of SHI irradiated glass is similar to the one of a hyper quenched glass.

  • D2 Raman band associated to 3 members ring is only observed in irradiated glass.

  • Irradiated state seems slightly different to an equilibrated liquid quenched rapidly.

Abstract

The effects of ion tracks on the structure of oxide glasses were examined by irradiating a silica glass and two borosilicate glass specimens containing 3 and 6 oxides with krypton ions (74 MeV) and xenon ions (92 MeV). Structural changes in the glass were observed by Raman and nuclear magnetic resonance spectroscopy using a multinuclear approach (11B, 23Na, 27Al and 29Si). The structure of irradiated silica glass resembles a structure quenched at very high temperature. Both borosilicate glass specimens exhibited depolymerization of the borosilicate network, a lower boron coordination number, and a change in the role of a fraction of the sodium atoms after irradiation, suggesting that the final borosilicate glass structures were quenched from a high temperature state. In addition, a sharp increase in the concentration of three membered silica rings and the presence of large amounts of penta- and hexacoordinate aluminum in the irradiated 6-oxide glass suggest that the irradiated glass is different from a liquid quenched at equilibrium, but it is rather obtained from a nonequilibrium liquid that is partially relaxed by very rapid quenching within the ion tracks.

Introduction

Glass is the primary containment barrier in the case of high-activity nuclear waste disposal. The minor actinides, fission products, and other elements in the vitrified waste solution form an integral part of the glass structure. The main sources of radiation are beta decay of fission products and alpha decay of the actinide elements. Spontaneous fission of some of the actinide isotopes and alpha–neutron reactions are also sources of fission fragments and neutrons, but these radiation sources can generally be ignored in disposal conditions because of their low production rates [1]. After a few centuries, most of the radioactivity will be due to alpha decay of minor actinides. It is therefore important to assess the impact of accumulated alpha decay damage on the glass structure.

Recent studies [2], [3] have shown that the alpha decay dose received by curium-doped glass has a direct impact on its fictive temperature and that the energy dissipated by the recoil nucleus during alpha disintegration results in the formation of a new structure similar to that of very rapidly quenched glass. This phenomenological description evokes the formation of ion tracks described by the inelastic thermal spike model [4], [5] during irradiation by swift heavy ions (SHI). In this model, the passage of a swift heavy ion produces a localized high energy deposit by electronic interaction, resulting in local melting along the ion track followed by very rapid thermal quenching. It is of interest to compare the consequences of this type of irradiation on oxide glasses with the consequences resulting from alpha decay of minor actinides.

The effects of ion tracks have been widely investigated in amorphous silica [6], [7], [8], [9], [10], [11], [12], [13], [14], [15] and metallic glass [10], [16], [17], [18] but no studies have been conducted to date on their impact on the structure of borosilicate glasses. The objective here was to assess the impact of ion tracks on simple borosilicate glass specimens (containing 3 and 6 oxides), which are in fact simplified versions of the French R7T7-type nuclear glass [19]. The glass specimens were irradiated by krypton ions (74 MeV) and xenon ions (92 MeV). A silica glass specimen was also irradiated to study the irradiation response of a simple single-oxide glass with anomalous high-temperature behavior compared to that of borosilicate glass [20]. The effect of irradiation on the glass structure was then examined by Raman spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Changes in the glass properties were observed by optical interferometry and micro-indentation.

Section snippets

Samples

A 1 mm thick Suprasil 300 glassy SiO2 plate was used as a reference material. The plate was cut into 1.5 × 1.5 cm samples.

The BS3 and BS6 glasses (see Table 1 for compositions) were synthesized by melting oxides, carbonates and nitrates. The mixture was melted for 3 h in a platinum–rhodium–yttrium crucible without stirring at 1523 K for the BS3 glass and 1673 K for the BS6 glass, and then poured into a graphite crucible. The glasses were then annealed above the glass transition point (∼873 K) from

Density variations

When subjected to ion irradiation several processes are known to lead to dimensional changes of glasses, density changes induced by the glass structural modifications, irradiation creep associated to stress relaxation and ion hammering induced by irreversible macroscopic deformations perpendicular to the ion path [33].

The density variation can be estimated from the step height and transverse step measurements performed by optical interferometry and knowing the damaged depth. The damaged depth

SiO2

After irradiation by 74 MeV krypton ions, silica exhibits about 3.3% densification and a 24% hardness decrease. This suggests that the observed decrease in hardness is not due to a decrease in the atomic density of the glass but more likely to an increase after irradiation in the concentration of weak points such as dangling bonds, as suggested by Bibent based on the infrared spectrum of silica after ion irradiation [54].

Irradiation also increases the intensity of the Raman D2 band at 607 cm1.

Conclusion

The behavior of two borosilicate glass compositions containing 3 and 6 oxides was evaluated under irradiation by 74 MeV krypton ions and 92 MeV xenon ions.

A combination of Raman spectroscopy analysis with a multinuclear NMR approach (11B, 23Na, 27Al and 29Si) has shown that the glass structure after irradiation resembles a vitreous state frozen from a very high-temperature liquid (depolymerization of the silicate network, lower boron coordination number, increased disorder) but also exhibits

Acknowledgments

This project was carried out under a research program jointly funded by CEA and AREVA.

References (84)

  • S. Kumar

    Study of tracks of heavy-ions in quartz glass

    Nucl. Instr. Meth. Phys. Res., Sect. A

    (1984)
  • J.P. Amoureux et al.

    Z filtering in MQMAS NMR

    J. Magn. Reson.

    (1996)
  • R.A.B. Devine

    Macroscopic and microscopic effects of radiation in amorphous SiO2

    Nucl. Instr. Meth. Phys. Res., Sect. B

    (1994)
  • S. Peuget

    Irradiation stability of R7T7-type borosilicated glass

    J. Nucl. Mater.

    (2006)
  • L.S. Du et al.

    Solid-state NMR study of metastable immiscibility in alkali borosilicate glasses

    J. Non-Cryst. Solids

    (2003)
  • F. Angeli

    Insight into sodium silicate glass structural organization by multinuclear NMR combined with first-principles calculations

    Geochim. Cosmochim. Acta

    (2011)
  • J.F. Stebbins

    Cation sites in mixed-alkali oxide glasses: correlations of NMR chemical shift data with site size and bond distance

    Solid State Ionics

    (1998)
  • J. Schneider

    Q(n) distribution in stoichiometric silicate glasses: thermodynamic calculations and Si-29 high resolution NMR measurements

    J. Non-Cryst. Solids

    (2003)
  • T. Nanba et al.

    A theoretical interpretation of the chemical shift of Si-29 NMR peaks in alkali borosilicate glasses

    Geochim. Cosmochim. Acta

    (2004)
  • F.L. Galeener

    Planar rings in glasses

    Solid State Commun.

    (1982)
  • T.F. Yang

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

    J. Non-Cryst. Solids

    (2011)
  • T. Yano

    Structural investigation of sodium borate glasses and melts by Raman spectroscopy. I. Quantitative evaluation of structural units

    J. Non-Cryst. Solids

    (2003)
  • T. Yano

    Structural investigation of sodium borate glasses and melts by Raman spectroscopy. II. Conversion between BO4 and BO2O-units at high temperature

    J. Non-Cryst. Solids

    (2003)
  • T. Yano

    Structural investigation of sodium borate glasses and melts by Raman spectroscopy. III. Relation between the rearrangement of super-structures and the properties of glass

    J. Non-Cryst. Solids

    (2003)
  • B.G. Parkinson

    Quantitative measurement of Q(3) species in silicate and borosilicate glasses using Raman spectroscopy

    J. Non-Cryst. Solids

    (2008)
  • K. Fukumi et al.

    Intensity of Raman bands in silicate-glasses

    J. Non-Cryst. Solids

    (1990)
  • D.R. Neuville

    Viscosity, structure and mixing in (Ca, Na) silicate melts

    Chem. Geol.

    (2006)
  • S. Peuget

    Comparison of radiation and quenching rate effects on the structure of a sodium borosilicate glass

    J. Non-Cryst. Solids

    (2013)
  • R. Akagi et al.

    Raman spectra of K2O–B2O3 glasses and melts

    J. Non-Cryst. Solids

    (2001)
  • P.F. McMillan

    A study of SiO2 glass and supercooled liquid to 1950 K via high-temperature Raman-spectroscopy

    Geochim. Cosmochim. Acta

    (1994)
  • M. Toulemonde

    Track creation in SiO2 and BaFe12O19 by swift heavy ions: a thermal spike description

    Nucl. Instr. Meth. Phys. Res., Sect. B

    (1996)
  • J.M. Delaye

    Molecular dynamics simulation of radiation damage in glasses

    J. Non-Cryst. Solids

    (2011)
  • S. Sen et al.

    Ionic conduction and mixed cation effect in silicate glasses and liquids: Na-23 and Li-7 NMR spin-lattice relaxation and a multiple-barrier model of percolation

    J. Non-Cryst. Solids

    (1996)
  • P. McMillan et al.

    Raman-spectroscopy of calcium aluminate glasses and crystals

    J. Non-Cryst. Solids

    (1983)
  • C.I. Merzbacher

    A high-resolution 29Si and 27Al NMR-study of alkaline-earth aluminosilicate glasses

    J. Non-Cryst. Solids

    (1990)
  • D.R. Neuville et al.

    Al environment in tectosilicate and peraluminous glasses: A Al-27 MQ-MAS NMR, Raman, and XANES investigation

    Geochim. Cosmochim. Acta

    (2004)
  • B.T. Poe

    Al and Si coordination in SiO2–Al2O3 glasses and liquids – a study by NMR and IR spectroscopy and MD simulations

    Chem. Geol.

    (1992)
  • J.F. Stebbins

    Temperature effects on non-bridging oxygen and aluminum coordination number in calcium aluminosilicate glasses and melts

    Geochim. Cosmochim. Acta

    (2008)
  • W.J. Weber et al.

    A review of radiation effects in solid nuclear waste forms

    Nucl. Technol.

    (1983)
  • E.A. Maugeri

    Calorimetric study of glass structure modification induced by α decay

    J. Am. Ceram. Soc.

    (2012)
  • M. Toulemonde et al.

    Transient thermal-process after a high-energy heavy-ion irradiation of amorphous metals and semiconductors

    Phys. Rev. B: Condens. Matter Mater. Phys.

    (1992)
  • M. Toulemonde

    Synergy of nuclear and electronic energy losses in ion-irradiation processes: the case of vitreous silicon dioxide

    Phys. Rev. B: Condens. Matter Mater. Phys.

    (2011)
  • Cited by (43)

    View all citing articles on Scopus
    View full text