Thermodynamic and magnetic properties of multicomponent (Fe, Ni)(70)Zr10B20 amorphous alloy powders made by mechanical alloying

The correlation between the thermodynamic and magnetic properties of mechan ically alloyed (MAed) (Fe1-xNix)(70)Zr10B20 (x = 0.1-0.4) amorphous alloy p owders was investigated. The activation energy (E-a) for primary crystalliz ation of the b.c.c. alpha -Fe: phase decreased significantly: from 356.7 to 139.7 kJ/mol with increasing Ni/Fe ratio from 0.11 to 0.43 and then increa sed to 304 kJ/mol for the alloy with a Ni/Fe ratio of 0.67. The Curie tempe ratures of the (Fe1-xNix)(70)Zr10B20 (x = 0.1-0.4) alloy powders milled at 18h were found to be in the range 425-625 K. The room temperature coercivit y of the as-milled amorphous powders was in the range 37-44 G. However, the y were dramatically reduced to values in the range 11-24 G after annealing at temperatures from 250 to 575 K. The minimum coercivities obtained after in situ annealing of amorphous powder were 8 G for (Fe0.6Ni0.4)(70)Zr10B20 and 10 G for (Fe0.8Ni0.2)(70)Zr10B20, respectively. (C) 2001 Elsevier Scien ce B.V. All rights reserved.