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Raman study of copper and iron oxide particles embedded in an SiO 2 matrix
Author(s) -
PérezRobles F.,
GarcíaRodríguez F. J.,
JiménezSandoval S.,
GonzálezHernández J.
Publication year - 1999
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/(sici)1097-4555(199912)30:12<1099::aid-jrs490>3.0.co;2-0
Subject(s) - maghemite , copper , hematite , raman spectroscopy , annealing (glass) , iron oxide , atmospheric temperature range , oxide , copper oxide , materials science , metallurgy , inorganic chemistry , chemistry , chemical engineering , mineralogy , analytical chemistry (journal) , environmental chemistry , physics , optics , meteorology , engineering
The structure of heat‐treated sol–gel‐made SiO 2 samples containing copper or iron in various amounts was studied using Raman spectroscopy and x‐ray diffraction. The treatments were in air in the temperature range 200–800 °C. Copper and iron concentrations were in the range 7–55 wt%. It was found that in the samples containing copper, the metal is mainly dissolved in the SiO 2 network when the thermal treatment is at low temperatures. For higher annealing temperatures, first a copper silicate is formed and then most of the copper forms cupric oxide particles at temperatures of about 800 °C. In samples containing iron, the formation of particles with nanometric size of the γ‐Fe 2 O 3 (maghemite) phase is observed after annealing at 500 °C. At 800 °C the maghemite phase is transformed into the stable hematite (α‐Fe 2 O 3 ) phase. Copyright © 1999 John Wiley & Sons, Ltd.