Comparative study of V and Mo on the glass formation and magnetic properties of Fe-Si-B-Cu-Nb-M (M = V, Mo) nanocrystalline for high frequency applications

This paper aimed at improving high-frequency magnetic properties and decreasing material cost of Finemetalloy without sacrificing saturation magnetization (Ms) and coercivity (Hc) by minor V and Mo substitution of Nb. Both V and Mo enhanced glass forming ability (GFA) and promoted the precipitation of primary alpha-Fe particles. Meanwhile, V addition hindered the precipitation of the secondary phase and consequently extended annealing temperature range. After annealing, the Fe73.5Si15.5B9Cu1Nb2V1 and Fe73.5Si15.5B9Cu1Nb2.5Mo0.5 have high Ms of 129.0 and 127.6 emu/g, low Hc of 2.7 and 5.3 A/m, and high ire of 3.6 x 10(4) and 3.4 x 10(4) at 200 kHz/0.3V respectively. The order of the effect of Nb, Mo and V on decreasing grain size and coercivity (Hc) is Nb>V>Mo. Besides, the increasing electrical resistivity via adding 1.0 at.% V and 0.5 at.% Mo contributed to a higher and more stable effective permeability (ire) in a wide high frequency range. These advantages for soft magnetic materials are promising for high-frequency applications.