Preparation of Fe{sub 3}O{sub 4} and {gamma}-Fe{sub 2}O{sub 3} powders by magnetomechanical activation of hematite

Journal Article · Tue Mar 01 04:00:00 EST 1994 · IEEE Transactions on Magnetics

DOI:https://doi.org/10.1109/20.312391· OSTI ID:40198

Kaczmarek, W A; Ninham, B W ^[1]

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1. Australian National Univ., Canberra (Australia). Research School of Physical Sciences and Engineering

Total phase transformation of hematite to magnetite was accomplished at room temperature by wet magnetomechanical activation of hematite. Low energy mechanical activation or the oxide surface is sufficient to effect the transformation. Oxygen bonds on {alpha}-Fe{sub 2}O{sub 3} oxide surface are apparently broken during the mechanical activation process and oxygen is released (removed) to the dispersing polar liquid. The oxygen pressure during the process as well the nature of the dispersing liquid have a critical Influence on successful and fast phase transformation. Thus, all preparations performed In air, dry conditions or with nonpolar hydrocarbons (benzene, anthracene) show that the process of hematite reduction Is non existent or very slow. Normal air pressure and/or application of hydrocarbons suppress the transformation.

• OSTI ID: 40198
• Report Number(s): CONF-930860--
• Journal Information: IEEE Transactions on Magnetics, Journal Name: IEEE Transactions on Magnetics Journal Issue: 2Pt2 Vol. 30; ISSN IEMGAQ; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CONTROLLED ATMOSPHERES
CRYSTAL-PHASE TRANSFORMATIONS
EXPERIMENTAL DATA
IRON OXIDES
MILLING