On the nature of features seen by tem in fast neutron irradiated Al2O3

Bunch, J.M.; Hoffman, Jacob B.; Zeltmann, A. H.

doi:10.1016/0022-3115(78)90480-4

Cited by 20 publications

(4 citation statements)

References 7 publications

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“…If this suggestion is correct, one would not expect colloids to be found in A1203 irradiated by fast neutrons, since in that case more equal numbers of displacements occur on the two sub-lattices. This would be consistent with the findings of Bunch et al 37 Noda et al 38 have studied Liz0 irradiated with thermal neutrons, which produce damage mainly through the 6Li(n, a)3H reaction which releases 4.79 MeV. ,4t doses in the range 1.5 x 1016-9.8 x lOI7 n cm-2 they observed an ESR spectrum with hyperfine structure expected for the F+ centre: an electron trapped at an oxygen vacancy.…”

Section: Background Work On Colloids I N Alkali Halidessupporting

confidence: 78%

Colloid formation in irradiated insulators

Hughés¹

1983

Radiation Effects

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Irradiation of ionic crystals causes the displacement of lattice ions and the formation of primary defects in the form of vacancies and interstitials. At high temperatures when these defects are mobile secondary defect reactions will produce various types of defect clusters. In some compounds clustering can lead to the formation of small particles of the metal constituent, referred to as colloids. A well-known example of this effect occurs in the alkali halides, where the colloids form as the result of large-scale aggregation of the primary F centres, so that the metallic region in this case derives from primary defects on the anion sublattice. The latent image of the photographic process in silver halides is also an example of the formation of a small metal colloid. and other crystals such as hydrides and azides can also be partially decomposed into metallic particles by irradiation with ionizing radiation. Recently metal colloids have been found as a result of displacement damage in the oxides Liz0 and AlzO:. This article reviews some of the background properties of colloids in ionic crystals and describes some examples of colloid formation by irradiation. Colloid growth in NaCl is described in more detail. since recent experimental and theoretical work provides a more complete picture than in other compounds. The Jain-Lidiard theory explains many features of the behaviour observed during high dose irradiation a t high temperatures, and some comments are made about ways in which the theory could be developed further.

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Section: Background Work On Colloids I N Alkali Halidessupporting

confidence: 78%

Colloid formation in irradiated insulators

Hughés¹

1983

Radiation Effects

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“…In fact, HVEM irradiation of alkali borosilicate glass produces, under appropriate conditions, large spherical regions where electrons are scattered much less than in the unirradiated area. These prevalent microstructures have shapes similar to those of gas filled bubbles as previously found in metals (24) and other insulators (25), and are unaffected by annealing at high temperature, contrary to what would be expected for voids nucleation. The interfaces between pairs of different sized cavities are curved in the direction expected from an inverse relationship between diameter and internal pressure.…”

Section: Nucleation and Growing Of Bubbles Under Electron Irpadiationmentioning

confidence: 76%

Radiation Damage of Glasses for Nuclear Waste Storage: Optical and Microstructural Aspects

Antonini

Camagni

Manara

et al. 1985

Glass … Current Issues

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615A possible way to achieve a stable nuclear waste form consists of incorporating the different radionuclides in borosilicate glasses. As a consequence of the long meanlife of some active species, e.g. actinides, radiation damage is produced in the storage matrix, which may potentially affect its long-ter~ stability.Glasses based on Si02 have a mixed ionic-covalent bonding, hence both ionization and atomic displacements are of relevance in determining the damage. Precursor atomic defects, present before irradiation, as well as added modifiers, including sodium, interact with the bombarding particles: y-rays, electrons, light and heavy ions. Under certain circumstances, individual defects tend to coalesce and defect clusters, usually in the form of gas bubbles, nucleate and grow.The overall damage thus consists of relatively strong modifications of the atomic bonding and of the local microstructure. Such modifications have been examined. Optical absorption spectra of pure Si02 provide the basis of interpretation for individual defects. Results of High Voltage Electron Microscopy, where irradiations and "in situ" observations take place simultaneously, allow to discuss the agglomeration effects.Both aspects of radiation damage are discussed in connection with the vitrification of nuclear waste, with special regard to possible implications upon the leaching of active species.

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“…In oxides radiation damage occurs predominantly by atomic collisions rather than by ionizing events, so that atoms on both sublattices will be displaced. There has been some doubt over whether metal colloids form in oxides such as A1203 and MgO irradiated to high doses with fast neutrons or electrons (84,85). Recently, Shikama and Pells (86) for the production of Al colloids from the appearance of electron diffraction patterns from f.c.c.…”

Section: Colloid Radius (Nm)mentioning

confidence: 99%

Formation of Clusters in Bulk Materials

Hughés

1986

Contribution of Clusters Physics to Materials Science and Technology

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On the nature of features seen by tem in fast neutron irradiated Al2O3

Cited by 20 publications

References 7 publications

Colloid formation in irradiated insulators

Colloid formation in irradiated insulators

Radiation Damage of Glasses for Nuclear Waste Storage: Optical and Microstructural Aspects

Formation of Clusters in Bulk Materials

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