Phase transformations and thermodynamic properties of oxide systems
https://doi.org/10.17073/0368-0797-2022-3-188-189
Abstract
A new approach to obtain amorphous oxides was investigated both theoretically and experimentally using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques. In this work, the conventional sol-gel method was modified by the addition of malic acid as an oxidizing agent and successfully applied to obtain two oxides Al2O3 & Fe2O3 with the amorphous structure. The results of the modified sol-gel method were compared to those obtained by thermal decomposition of corresponding salts, and the advantage of new technique was clearly demonstrated. Thermal stability of the obtained amorphous oxides was examined by the differential scanning calorimetry (DSC). It was found that amorphous Al2O3 is stable up to 790 – 810 °C, while amorphous Fe2O3 recrystallises at about 160 – 180 °C, depending on the heating rate.
About the Authors
M. S. Derevyanko
National University of Science and Technology “MISIS”
Russian Federation
Russian Federation
Maksim S. Derevyanko, Postgraduate of the Chair “Physical Chemistry”,
Engineer of the Scientific Research Center “Thermochemistry of Materials”
4 Leninskii Ave., Moscow 119049
A. V. Kondrat’ev
National University of Science and Technology “MISIS”
Russian Federation
Russian Federation
Aleksandr V. Kondrat’ev, Cand. Sci. (Eng.), Senior Researcher of the
Scientific Research Center “Thermochemistry of Materials”
4 Leninskii Ave., Moscow 119049
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Review
For citations:
Derevyanko M.S., Kondrat’ev A.V. Phase transformations and thermodynamic properties of oxide systems. Izvestiya. Ferrous Metallurgy. 2022;65(3):188-189. (In Russ.) https://doi.org/10.17073/0368-0797-2022-3-188-189
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