Studies on the formation of γ-Fe2O3 by thermal decomposition of ferrous malate dihydrate
1993; Elsevier BV; Volume: 219; Linguagem: Inglês
10.1016/0040-6031(93)80504-4
ISSN1872-762X
AutoresA.K. Nikumbh, A.A. Latkar, M.M. Phadke,
Tópico(s)Thermal and Kinetic Analysis
ResumoFerrous malate dihydrate (FeC4H4O5 · 2H2O) was prepared and its thermal decomposition studied by means of simultaneous thermal analysis (TGA, DTA, DTG) curves supplemented with two-probe d.c. electrical conductivity measurements under the atmospheres of static air, dynamic nitrogen and dynamic air. Dynamic air containing water vapour was found to be the most suitable atmosphere for the synthesis of γ-Fe2O3. The isothermal decomposition of FeC4H4O5 · 2H2O for various intermediate phases occurring at different ranges of temperature under the above atmospheres was studied using IR spectral studies, C and H analyses and X-ray diffraction data. This study reveals the formation of the anhydrous carboxylate (FeC4H4O5), which then oxidatively decomposes to α-Fe2O3, with probable intermediates FeO and Fe34v, along with some FeC4H4O5 and γ-Fe2O3. Both polar and non-polar gases were obtained during the decomposition of FeC4H4O5 · 2H2O under nitrogen atmosphere; these were analysed using gas-liquid chromatography. The γ-Fe2O3 synthesized was characterized by X-ray diffraction, magnetic hysteresis, scanning electron microscopy and Mössbauer spectroscopy.
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