Please use this identifier to cite or link to this item: http://hdl.handle.net/10773/20705
Title: Redox stability and high-temperature electrical conductivity of magnesium-and aluminium-substituted magnetite
Author: Kovalevsky, A. V.
Yaremchenko, A. A.
Naumovich, E. N.
Ferreira, N. M.
Mikhalev, S. M.
Costa, F. M.
Frade, J. R.
Keywords: MOLTEN IRON-OXIDE
THERMAL-EXPANSION
SPINEL
THERMOPOWER
SIMULATION
PROGRAM
GULP
MN
Issue Date: 2013
Publisher: ELSEVIER SCI LTD
Abstract: Spinel-type magnetite-based oxides, possessing relatively high electrical conductivity, are considered as promising consumable anode materials for high temperature pyroelectrolysis, a breakthrough low-CO2 steel technology to overcome the environmental impact of classical extractive metallurgy. The present work was focused on the analysis of phase stability, thermal expansion and high-temperature electrical conductivity in (Fe,Mg,Al)(3)O-4 system under oxidizing and mildly reducing conditions. Metastable, nearly single-phase at room temperature (Fe,Mg,Al)(3)O-4 ceramics was obtained by sintering at 1753-1773 K for 10 h in argon atmosphere. Thermal expansion and redox induced dimensional changes were studied on heating, using TG, XRD and dilatometry. The results revealed that magnesium improves the tolerance against oxidative decomposition and minimizes unfavorable dimensional changes in ceramic samples upon thermal cycling. Co-substitution of iron with aluminium and magnesium was proved to be a promising strategy for improvement of refractoriness and phase stability of Fe3O4-based spinels at elevated temperatures, without significant reduction in the electrical conductivity. (C) 2013 Elsevier Ltd. All rights reserved.
Peer review: yes
URI: http://hdl.handle.net/10773/20705
DOI: 10.1016/j.jeurceramsoc.2013.04.008
ISSN: 0955-2219
Publisher Version: 10.1016/j.jeurceramsoc.2013.04.008
Appears in Collections:CICECO - Artigos



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