Phase transition in WO₃ microcrystals obtained by sintering process

Abstract

Abstract 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.