COMPOSITIONAL EVOLUTION AND MAGNETIC-PROPERTIES OF NANOCRYSTALLINE FE81.5CU0.5MO0.5P12C3SI2.5

Tile amorphous alloy Fe81.5P12C3Cu0.5Mo0.5Si2.5 has been prepared and the crystallized alloy exhibits an ultrafine structure with a grain si ze of about 20 nm and excellent soft magnetic properties. The coercivi ty and the core loss as low as 5.7 A/m, 0.26 W/kp, respectively, and t he maximum permeability as high as 10.2x10(4) at an optimal annealing temperature of about 360 degrees C were obtained. By means of x-ray di ffraction, transmission electron microscope, and Mossbauer spectroscop y measurements, microstructures of the allay were investigated as a fu nction of the annealing temperature. The primary crystallization produ ces ultrafine grains of alpha-Fe(Si) solid solution with a grain size of about 20 nm precipitated in the residual amorphous matrix. The Si i n the cu Phase was estimated near to be completely disorder ranged and the Si concentration was determined to be about 2%-5%. The Fe3P phase appears in the residual amorphous phase upon annealing ar 420 degrees C. (C) 1996 American Institute of Physics.