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7616810 
Journal Article 
PREPARATION OF FE3O4 AND GAMMA-FE2O3 POWDERS BY MAGNETOMECHANICAL ACTIVATION OF HEMATITE 
Kaczmarek, WA; Ninham, BW; , 
1994 
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 
NEW YORK 
732-734 
WOS:A1994NU01300091 
Total phase transformation of hematite to magnetite was accomplished at room temperature by wet magnetomechanical activation of hematite. Low energy mechanical activation of the oxide surface is sufficient to effect the transformation. Oxygen bonds on alpha-Fe2O3 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 or 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. 
5th European Magnetic Materials and Applications Conference (EMMA 93) 
KOSICE, SLOVAKIA