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Author Santarosa, M. ♦ Speghini, A. ♦ Bettinelli, M. ♦ Righi, L. ♦ Calestani, G. ♦ Gemmi, M. ♦ Migliori, A.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CRYSTAL STRUCTURE ♦ CRYSTAL-PHASE TRANSFORMATIONS ♦ BISMUTH OXIDES ♦ LEAD OXIDES ♦ X-RAY DIFFRACTION ♦ ELECTRON DIFFRACTION ♦ HEAT TREATMENTS ♦ EXPERIMENTAL DATA
Abstract Samples with Bi{sub 8}Pb{sub 5}O{sub 17} stoichiometry were synthesized by ceramic techniques at temperatures ranging from 200 to 640 C. Their structural properties and relative stabilities were investigated using X-ray and electron diffraction, differential scanning calorimetry, and Raman spectroscopy. The tetragonal {beta}{sub 2} phase is described by an incommensurately modulated structure, whose modulation depends on the firing temperature. Heat treatments in the 200--300 C range lead to the formation of a new tetragonal phase, {chi}, which is converted back to {beta}{sub 2} above 300 C. The intermediate {phi} phase can be obtained without the previous formation of {beta}{sub 2}, and its X-ray powder diffraction pattern is indexed using a triclinic cell. The present data suggest that the {beta}{sub 2} phase is the low-temperature polymorph of this composition.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-05-01
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 144
Issue Number 2


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