Abstract
Ultrafine iron particles were prepared by the reduction of ferrous salts with aqueous sodium borohydride in the presence of surfactant. Particles of about 100Å were observed with an electron microscope among the iron particles prepared in the presence of sodium oleate or duomeen-TDO. When the concentration ratio of oleate to ferrous ion increased in the vicinity under critical micelle concentration of oleate, FWHM (full width at half maximum) in the reflection of the (110) plane by x-ray diffraction, the specific surface area and adsorbed amount of oleate, of resultant α-iron increased. Also, remanent magnetization and coercive force decreased with the increase of concentration ratio of oleate to ferrous ion in the reactive solution. The results mentioned above supposed the decrease of iron particle size. However, a stable iron particle suspension could be prepared, if thickness of adsorbed surfactant layer is increased.
