Effect of Ni addition on the glass-forming ability and soft-magnetic properties of FeNiBPNb metallic glasses

Abstract

The effect of Ni addition on the glass-forming ability (GFA) and soft-magnetic properties of an (Fe1−x Ni x )75.5B14.5P7Nb3 (x=0−0.6) alloy system were investigated. We found that the addition of Ni was effective in allowing the alloy to approach a eutectic point as well as increasing the thermal stability of the supercooled liquid. By increasing the amount of Ni, the supercooled liquid region (ΔT x), the reduced glass transition temperature T rg (T g/T l) and the γ parameter [T x/(T g+T l)] increased from 49 to 75 K, 0.540 to 0.594 and 0.373 to 0.405, respectively. As a result, novel (Fe1−x Ni x )75.5B14.5P7Nb3 bulk metallic glass (BMG) rods with a maximum diameter of 1 mm were synthesized with a composition of x=0.5 and x=0.6 by copper mold casting. These metallic glasses have a moderate saturation magnetization of 0.37–1.20 T with good soft-magnetic properties, i.e. a low coercivity of 1.4–3.3 A/m and a high effective permeability of 13100–20900 at 1 kHz. The simultaneous achievement of a high GFA and good soft-magnetic properties for the FeNi-based alloy system is promising for the future development of BMGs.