On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study.

Rios, S. and Martin, C. M. and Whittle, K. R. (2005) On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study. Zeitschrift für Kristallographie, 220. pp. 748-755. DOI 10.1524/zkri.220.8.748.67082

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Abstract

Nanoscale structural features of amorphous zircon and pyrochlore produced by self-irradiation induced amorphization have been characterized by small-angle xray scattering (SAXS). Electron density fluctuations were observed in the untreated samples and studied as a function of annealing temperature (up to 1300 C). In untreated zircon, density fluctuations were found to have a characteristic length-scale of approximately 1 nanometer diameter. A clear scattering maximum develops at 3 nm1 as a function of the degree of damage, but only for amorphous fractions higher than 70%. For the untreated pyrochlore sample such a strong signal was not observed in the scattering function. As annealing temperature increases, phase segregation is observed in zircon with a clear nucleation at 850 C of zirconia grains. The SAXS contribution, however, points towards a lower nucleation temperature, ca. 700 C. In the pyrochlore structure, at temperatures as low as 300 C the appearance of a first crystalline phase, Ca2Nb2O7, is observed, with the subsequent crystallization of TiO2 at 800 C. Observed electron density variations are compared between the two structures and discussed in terms of nanoscale phase segregation phenomena.

Item Type: Article
Uncontrolled Keywords: 2005 AREP IA46 IA49 2005 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Zeitschrift für Kristallographie
Volume: 220
Page Range: pp. 748-755
Identification Number: 10.1524/zkri.220.8.748.67082
Depositing User: Sarah Humbert
Date Deposited: 19 Aug 2010 09:07
Last Modified: 23 Jul 2013 09:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/1800

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