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.
keywords
MOLTEN IRON-OXIDE; THERMAL-EXPANSION; SPINEL; THERMOPOWER; SIMULATION; PROGRAM; GULP; MN
subject category
Materials Science
authors
Kovalevsky, AV; Yaremchenko, AA; Naumovich, EN; Ferreira, NM; Mikhalev, SM; Costa, FM; Frade, JR
our authors
Aleksey Yaremchenko
Principal Researcher
Andrei Kavaleuski
Principal Researcher
Jorge Ribeiro Frade
Retired Professor
Nuno Miguel Freitas Ferreira
Post-Doc Fellowship
Sergey Mikhalev
Post-Doc FellowshipProjects
acknowledgements
Research leading to these results has received support from the European Union's Research Fund for Coal and Steel (RFCS) research program, under grant agreement IERO-RSF-PR-09099, from the European Commission within the project NMP2/CT/2004/515960