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Manganese ferrite synthesized from Mn(II) acetate + hematite freeze-dried powders
Freeze-drying was used to obtain a homogeneous fine powder containing (CH 3COO) 2Mn·2H 2O and α-Fe 2O 3 (molar ratio Fe:Mn = 3:1), which was thermally treated for 2 h in N 2 atmosphere, at 400 °C. This composite system was further annealed for 4 h in the same atmosphere, either at 700 °C or at 1000...
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Published in: | Materials chemistry and physics 2007-09, Vol.105 (1), p.92-98 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Freeze-drying was used to obtain a homogeneous fine powder containing (CH
3COO)
2Mn·2H
2O and α-Fe
2O
3 (molar ratio Fe:Mn
=
3:1), which was thermally treated for 2
h in N
2 atmosphere, at 400
°C. This composite system was further annealed for 4
h in the same atmosphere, either at 700
°C or at 1000
°C. The 700
°C annealed sample was thermally treated in air at 1200
°C and then rapidly quenched. The phase transformations that occurred in the freeze-dried and heat-treated powders were investigated by thermal analyses, X-ray diffractometry, scanning electron microscopy and Mössbauer spectroscopy. Results showed that MnO–α-Fe
2O
3–Fe
3O
4 compounds were obtained after the first heat-treatment. Samples subsequently annealed in N
2 atmosphere revealed the formation of Fe-rich manganese ferrites and manganowüstite phases. However, a single spinel phase was obtained for the sample that had been annealed and quenched in air. |
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ISSN: | 0254-0584 1879-3312 |
DOI: | 10.1016/j.matchemphys.2007.04.005 |