Fe2O3/aluminum thermite reaction intermediate and final products characterization

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:465

Article

Duraes, Luisa ; Costa, Benilde F. O. ; Santos, Regina ; Correia, Antonio ; Campos, Jose ; Portugal, Antonio

关键词: thermite;    iron oxide/aluminum reaction;    products characterization;    X-ray diffraction;    Mossbauer spectroscopy;    reaction mechanism;   

DOI  :  10.1016/j.msea.2007.03.063

来源: Elsevier

【 摘 要 】

Radial combustion experiments on Fe2O3/aluminumtherrnite thin circular samples were conducted. A stoichiometric (Fe2O3 + 2Al) and four over aluminized mixtures were tested. The combustion products were characterized by X-ray diffraction and Mossbauer spectroscopy and the influence of Fe2O3/aluminum ratio on their composition was assessed. The main products were identified as alumina (alpha-Al2O3) and iron (Fe). A significant amount of hercynite (FeAl2O4) was detected, decreasing with the aluminum excess in the reactants. Close to the sample/confinement interface, where reaction quenching occurs, a non-stoichiometric alumina (Al2.667O4) was observed, being its XRD intensity correlated to the hercynite amount. Fe3Al intermetallic phase was found in the products of over aluminized mixtures. A reaction mechanism was proposed comprising: (i) Fe2O3 reduction to Fe3O4 and FeO; (ii) Al oxidation to Al2O3; (iii) interaction of the remaining Al with Fe3O4 and FeO with formation of iron-aluminates (hercynite) and iron; (iv) for the over aluminized mixtures, incorporation of Al into the iron-aluminates takes place with the formation of iron and alumina and, in parallel, Al reacts with iron to produce intermetallics. (C) 2007 Elsevier B.V. All rights reserved.

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