Enhanced glass forming ability and excellent saturation magnetic flux density by V addition in FeSiBPCCu amorphous/noncrystalline alloys

Abstract

To overcome the trade-off between high saturation magnetization (Bs) and poor glass forming ability (GFA) for Fe-based alloys, the GFA, nanocrystallization and soft magnetic properties of Fe83.5Si1B9.2P5C0.5Cu0.8-xVx (x = 0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8 at%) alloys were investigated. It is shown that the critical thickness of as-quenched amorphous ribbons can be increased from 24 μm to 35 μm with the increase of V, which is significant to the mass production of amorphous ribbons, from 0 to 0.8 at%,. Excellent magnetic properties have been achieved by tailoring the V/Cu ratio and annealing temperatures. The amorphous alloys with more than 0.4 at% V exhibit Bs above 1.73 T and coercivity (Hc) lower than 4.1 A/m, and nanocrystalline alloys with less than 0.4 at% V exhibit Bs above 1.8 T and Hc lower than 10 A/m, respectively. This research discusses the structural mechanism underlying the magnetic properties of amorphous/nanocrystalline alloys. It also confirms that the formation of amorphous structure with high enhanced stability and the nanocrystallization of α-Fe(Si) grains with the average size about 23 nm are keynotes for these soft magnetic materials.