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

Langhof N, Göbbels M (2009)

Publication Language: English

Publication Type: Journal article

Publication year: 2009

Journal

Journal of Solid State Chemistry Elsevier

Publisher: Elsevier

Book Volume: 182

Pages Range: 2725-2732

Journal Issue: 10

DOI: 10.1016/j.jssc.2009.07.024

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 Sr^{2 +}1 - x La^{3 +}x Fe^{2 +}x - y Co^{2 +}y Fe^{3 +}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.

Authors with CRIS profile

Matthias Göbbels 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://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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