Fe-based nanocrystalline soft magnetic alloys for high-temperature applications

We report on improved high-temperature soft magnetic properties in Fe88−2xCoxNixZr7B4Cu1 nanocrystalline alloys. Substituting 5.5 at. % Co and Ni for Fe enhances the magnetization by 5% at ambient temperature and by 30% at 650 °C. The Curie temperature of the residual amorphous phase is also raised significantly (from 67 °C for x=0 to 298 °C for x=5.5), resulting in low coercivities (<30 A m−1) for Fe77Co5.5Ni5.5Zr7B4Cu1 over the temperature range 50–500 °C. The higher magnetization and Curie temperature as compared with other Fe-based alloys, and smaller Co content as compared with (Fe,Co)-based alloys, make this alloy attractive as an affordable high-temperature soft magnetic material.