Structure-property Relations of Binary Ferrite Melts

Author

C. J. Benmore
C. Shi
O. L.G. Alderman
J. P. Harvey
D. Lipke, Missouri University of Science and TechnologyFollow
J. K.R. Weber

Abstract

Molten ferrite systems are used in the smelting and refining processes in steelmaking, to reduce the loss of metals in slags and to accelerate reaction rates. Here, high-energy x-ray diffraction experiments have been performed on aerodynamically levitated molten spheres of 43BaO-57FeOX and 43SrO-57FeOX at 1873 K using laser beam heating. The composition was varied within the range of x = 1-1.5 by changing the oxygen partial pressure of the levitation gas. The corresponding x-ray pair distribution functions have been interpreted using empirical potential structure refinement (EPSR) modeling. In oxygen-rich melts (x = 1.5), our EPSR models indicate very similar structures for the different alkaline-earth liquids, with both the Ba-O and Sr-O coordination numbers to be ∼8.4 and the total Fe-O coordination numbers ∼5.7. However, our models show that in reducing environments, the Fe3+ and Fe2+ ions exhibit very different behaviors in the Ba- and Sr-ferrite liquids. In the Ba-ferrite melt, the Fe3+-O coordination number decreases from 5.7 (at x = 1.5) to 5.2 (at x = 1.07), whereas Fe2+-O remains constant at ∼5.0 across the same compositional range. In the Sr melts, both the Fe2+-O and Fe3+-O coordination numbers rise from ∼5.7 (at x = 1.5) to 6.3 (at x = 1.07). All models show the structures to be heterogeneous with intertwined nanometer sized clusters or channels of Ba/Sr-O and Fe-O polyhedra that grow as oxygen content is reduced. Changes in the viscosity and electrical properties are interpreted in terms of the number of bridging and non-bridging oxygens associated with FeO4 tetrahedra and concentration of charge carriers, respectively.

Recommended Citation

C. J. Benmore et al., "Structure-property Relations of Binary Ferrite Melts," Journal of Applied Physics, vol. 137, no. 8, article no. 085903, American Institute of Physics, Feb 2025.

The definitive version is available at https://doi.org/10.1063/5.0242452

Department(s)

Materials Science and Engineering

Comments

Basic Energy Sciences, Grant 201706890053

International Standard Serial Number (ISSN)

1089-7550; 0021-8979

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2025 American Institute of Physics, All rights reserved.

Publication Date

28 Feb 2025