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Phase transition in WO 3 microcrystals obtained by sintering process
Author(s) -
Filho A. G. Souza,
Filho J. Mendes,
Freire V. N.,
Ayala A. P.,
Sasaki J. M.,
Freire P. T. C.,
Melo F. E. A.,
Julião J. F.,
Gomes U. U.
Publication year - 2001
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.727
Subject(s) - monoclinic crystal system , triclinic crystal system , raman spectroscopy , sintering , phase transition , crystallography , atmospheric temperature range , materials science , ceramic , phase (matter) , mineralogy , analytical chemistry (journal) , chemistry , crystal structure , metallurgy , thermodynamics , organic chemistry , optics , physics
The vibrational properties of WO 3 ceramics in the 30–300 K temperature range were probed by Raman spectroscopy. Starting with WO 3 ceramics at room temperature presenting monoclinic (V) and triclinic (VI) mixed phases, structural transitions related to decreasing temperature were observed. At low temperatures a monoclinic (VII) and a new mixed phase were observed, the former characteristic of WO 3 bulk and the latter associated to microcrystals. The analysis of the spectra indicated that the new phase develops gradually and it comes mainly from the monoclinic (V) phase. Copyright © 2001 John Wiley & Sons, Ltd.