Hexaferrites an phase relations in the iron-rich part of the system Sr-La-Co-Fe-O

Journal article


Publication Details

Author(s): Langhof N, Göbbels M
Journal: Journal of Solid State Chemistry
Publisher: Elsevier
Publication year: 2009
Volume: 182
Journal issue: 10
Pages range: 2725-2732
ISSN: 0022-4596
Language: English


Abstract


The iron rich part of the system was examined in the temperature range of 1200-1380 °C in air, with focus on the solid solutions of M-type hexaferrites. Samples of suitable compositions were studied by electronprobe microanalysis (EPMA). Substituted Sr-hexaferrites in the system Sr-La-Co-Fe-O do not follow the 1:1 substitution mechanism of La/Co in M-type ferrites. Due to the presence and limited Co2+-incorporation Fe3+-ions are reduced to Fe2+ within the crystal lattice to obtain charge balance. In all examined M-type ferrites divalent iron is formed, even at 1200 °C. The substitution principle Sr2++Fe3+↔La3++(Fe2+, Co2+) yields to the general substitution formula for the M-type hexaferrite Sr2 +1 - x La3 +x Fe2 +x - y Co2 +y Fe3 +12 - x O19 (0≤x≤1 and 0≤y≤x). In addition Sr/La-perovskiteSS (SS=solid solution), Co/Fe-spinelSS, hematite and magnetite are formed. Sr-hexaferrite exhibits at 1200 °C a limited solid solution with small amounts of Fe2+ (SrFe12O19↔Sr0.3La0.7Co 0.5Fe2+0.2Fe11.3O 19). At 1300 and 1380 °C a continuous solid solution series of the M-type hexaferrite is stable. SrFe12O19 and LaCo0.4Fe2+0.6Fe11O 19 are the end members at 1300 °C. The maximum Fe2+O content is about 13 mol% in the M-type ferrite at 1380 °C LaCo0.1Fe2+0.9Fe11O19 © 2009 Elsevier Inc. All rights reserved.



FAU Authors / FAU Editors

Göbbels, Matthias Prof. Dr.
Lehrstuhl für Mineralogie


How to cite

APA:
Langhof, N., & Göbbels, M. (2009). Hexaferrites an phase relations in the iron-rich part of the system Sr-La-Co-Fe-O. Journal of Solid State Chemistry, 182(10), 2725-2732. https://dx.doi.org/10.1016/j.jssc.2009.07.024

MLA:
Langhof, Nico, and Matthias Göbbels. "Hexaferrites an phase relations in the iron-rich part of the system Sr-La-Co-Fe-O." Journal of Solid State Chemistry 182.10 (2009): 2725-2732.

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Last updated on 2018-09-08 at 14:53