FORMATION AND MAGNETIC-PROPERTIES OF NANOCRYSTALLINE MECHANICALLY ALLOYED FE-CO AND FE-NI

Fe100-xCox, and Fe100-xNix powders were prepared by mechanical alloying of the elements in a planetary ball mill. They were investigated with respect to phase formation and magnetic properties using x-ray diffraction and measurements of the saturation magnetization and the coercivity. In both systems, disordered solid solutions were formed by mechanical alloying as proved especially by the measurement of the saturation magnetization. Moreover, nonequilibrium microstructures were established consisting in a nanocrystalline state (average minimum grain sizes 20-30 nm) accompanied by the introduction of considerable atomic-level strain (root mean square strain up to 1%). The soft magnetic behavior of this material shows some features of rapidly quenched nanocrystalline ribbons, but very low coercivities are prevented by a predominant influence of strain via magnetoelastic interaction.