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

To overcome the trade-off between high saturation magnetization ( B s ) and poor glass forming ability (GFA) for Fe-based alloys, the GFA, nanocrystallization and soft magnetic properties of Fe 83.5 Si 1 B 9.2 P 5 C 0.5 Cu 0.8- x V x ( 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 B s above 1.73 T and coercivity ( H c ) lower than 4.1 A/m, and nanocrystalline alloys with less than 0.4 at% V exhibit B s above 1.8 T and H c 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. • Minor V is benefit to improve GFA and magnetic proprieties of FeSiBPCCu. • Large critical thickness (35 μm) of as-quenched amorphous ribbons. • Amorphous Fe 83.5 Si 1 B 9.2 P 5 C 0.5 Cu 0.2 V 0.6 exhibits H c of 3.2 A/m and B s of 1.73 T. • Nanocrystalline alloys exhibit H c lower than 10A/m and B s above 1.8 T.