High Bs nanocrystalline Fe84−x−yCuxNbySi4B12 alloys (x=0.0–1.4, y=0.0–2.5)

In this study, Cu and Nb content dependences of magnetic properties for annealed Fe84−x−yCuxNbySi4B12 alloy ribbons fabricated by melt spinning were investigated. In Fe83−xCuxNb1Si4B12 alloy systems, the coercivity Hc markedly decreases with increasing x and exhibits a minimum at around x=1.0–1.2, while the saturation magnetic flux density Bs shows a slight variation. In Fe83−yCu1NbySi4B12 alloy systems, Hc markedly decreases at around y=0.5, while Bs shows a monotonic decrease. Fe82Cu1Nb1Si4B12 nanocrystalline alloy ribbons exhibit a high Bs of 1.78 T and a low Hc of 3.2 A/m. The core losses of the present alloys at 1.0 T at 400 Hz, P10/400, and at 1.0 T at 1 kHz, P10/1k, are 1.3 and 4.4 W/kg, respectively.