Magnetic properties of fine Fe-B particles

The magnetic properties of fine Fe-B particles with different boron concentrations and particle sizes were studied. The powders were prepared by reducing Fe-salts with NaBH/sub 4/ as a reducing agent in aqueous solution. The particle size ranged from 300 to 600 AA. X-ray diffraction patterns show that the particles are crystalline for boron concentrations less than 20 at.% and amorphous for greater concentrations. The maximum coercivity and saturation magnetization obtained for these particles are approximately 1200 Oe and 160 emu/g at room temperature. The coercivities are about two orders of magnitude higher than the values reported for Fe-B metallic glasses and alpha -Fe.<
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