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

Fe100-xCox, and Fe100-xNix powders were prepared by mechanical alloyin g of the elements in a planetary ball mill. They were investigated wit h respect to phase formation and magnetic properties using x-ray diffr action and measurements of the saturation magnetization and the coerci vity. In both systems, disordered solid solutions were formed by mecha nical alloying as proved especially by the measurement of the saturati on magnetization. Moreover, nonequilibrium microstructures were establ ished consisting in a nanocrystalline state (average minimum grain siz es 20-30 nm) accompanied by the introduction of considerable atomic-le vel strain (root mean square strain up to 1%). The soft magnetic behav ior of this material shows some features of rapidly quenched nanocryst alline ribbons, but very low coercivities are prevented by a predomina nt influence of strain via magnetoelastic interaction.