Microstructure and soft-magnetic properties of FeCoPCCu nanocrystalline alloys

Abstract Fe 83.2-x Co x P 10 C 6 Cu 0.8 (x = 0, 4, 6, 8 and 10) alloys with a high amorphous-forming ability and good soft-magnetic properties were successfully synthesized. Saturation magnetic flux density (B s ) is effectively enhanced from 1.53 T to 1.61 T for as-quenched alloy by minor Co addition, which is consistent well with the result of the linear relationship between average magnetic moment and magnetic valence. For Co-contained alloys, the value of corecivity (H c ) is mainly determined by magneto-crystalline anisotropy, while effective permeability (μ e ) is dominated by grain size and average saturation polarization. After proper heat treatment, the Fe 79.2 Co 4 P 10 C 6 Cu 0.8 nanocrystalline alloy exhibited excellent soft-magnetic properties including a high B s of 1.8 T, a low H c of 6.6 A/m and a high μ e of 15510, which is closely related to the high volume fraction of α-(Fe, Co) grains and refined uniform nanocrystalline microstructure.