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Annealing Metamict Zircon: A Powder X‐ray Diffraction Study of a Highly Defective Phase
Author(s) -
Colombo Monica,
Chrosch Jutta,
Salje Ekhard K. H.
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb02146.x
Subject(s) - metamictization , rietveld refinement , annealing (glass) , powder diffraction , crystallography , crystallinity , materials science , zircon , diffraction , x ray crystallography , crystal structure , mineralogy , chemistry , optics , geology , metallurgy , physics , paleontology
The transition from highly defective (metamict) to crystalline zircon is characterized by short‐range structural order, which follows a different kinetic behavior than the corresponding long‐range order. Experimental results from in situ powder X‐ray diffraction experiments are analyzed using Rietveld refinement and direct Fourier analysis. The Rietveld refinement leads to a detailed assessment of the structural contraction of the crystalline portion of the same during thermal annealing. The Fourier analysis shows a highly heterogeneous distribution of interatomic bond distances. The main effect of structural annealing is a change of the distances between Si and O atoms and the average Si–Zr distance. The Zr–Zr distance seems to be less affected by this thermal treatment. Short‐range order is recovered at lower temperatures than that of long‐range order. Crystallinity is recovered anisotropically with slower annealing along the crystallographic c ‐direction than along the a ‐direction.