Excellent high-temperature magnetic softness in a wide temperature for FeCo-based nanocrystalline alloy

Structure and initial permeability (mu(i)) of as-quenched and annealed (Fe-1 (-) Co-x(x))(72.7)Al0.8Si17.5B5Cu1Nb3 (x = 0,0.5) alloys were investigated. Substituting 50 at.% Co for Fe enhances both the Curie temperature of amorphous alloy, T-c(A), from 325 to 375 degrees C and the secondary crystallization temperature Tom, for delaying the formation of Fe-B hard magnetic phase from 720 degrees C to 729 degrees C. The correlation between initial permeability and temperature (mu(i)-T curve) for (Fe0.5Co0.5)(72.7)Al0.8Si17.5B5Cu1Nb3 alloys heating-cooling cycled at 510-640 degrees C was mainly analyzed. The optimum high temperature magnetic softness was found in 550 degrees C-annealed sample, the mu(i) can maintain above 1400 and shows roughly a horizontal linear correlation with T from room temperature up to 600 degrees C, which make this alloy attractive as an affordable high-temperature soft magnetic material. (C) 2015 Elsevier B.V. All rights reserved.