J. Phys. IV France 07 (1997) C1-613-C1-614
Aluminium Substituted Magnetite by Wet MethodY. Okano, N. Uchida and T. Nakamura
R&D division, Toda Kogyo Corporation, 4-1-2, Funairi-minami, Naka-ku, Hiroshima 730, Japan
Aluminium substituted magnetite particles with Al3+ content in the range from 0.7 to 4.0wt% were synthesized by the hydrothermal oxidation reaction. It was found that the mixing procedure was critical to prepare single-phase ferrite particles : it was required that Al ions were neutralized before the precipitation of Fe ions. As the aluminium content increases, the magnetization of the obtained particles decreased in the range from 86 to 60emu/g. The lattice constant also decreased from 0.840 to 0.836nm. XPS analysis indicated that aluminium in the obtained particles was both in hydroxide and oxide states, and that the molar fraction of them was approximately 20% and 80%, respectively. The lattice constant was in good agreement with the calculated value using the Vegard's law in Fe3O4- γ-Fe2O3-FeAl2O4 solid solution and taking into account of the existence of aluininium hydroxide.
© EDP Sciences 1997