Development of high Bs Fe–Ni-based metal amorphous nanocomposite by optimization of glass-forming ability

Abstract

Thermocalc simulations identified compositions with good glass-forming ability (GFA) by locating minima in liquidus temperature, and solidification range in (Fe70 Ni30)x(B-Si-Nb)100-x alloys with x = 82% and x = 85%, increased compared to previously developed x = 80% alloys. 3 compositions in the x = 82% system and 1 in the x = 85% system were successfully cast as amorphous magnetic ribbon. Magnetic properties of as-cast alloys showed improvements in Curie temperature and saturation induction, especially for the 85% alloy. Crystallization behavior in the 85% alloy was determined to occur as a 2-step process. Annealing studies showed (Fe70Ni30)82Nb2Si0B16 and (Fe70Ni30)82Nb3Si0B15 alloys to exhibit low coercivity and high Bs with annealing. TEM results show significant crystallization in as-cast ribbon. The (Fe70Ni30)85Nb0.5Si0B14.5 alloy as-cast has small, uniformly distributed grains, allowing a useful nanocrystalline alloy to be produced as cast. Finally, the parameter ΔTxg, the temperature range in which the material can be thermomechanically processed, was in the range of 12–23 °C.