Effect of Mo addition on high-temperature soft magnetic properties for air annealed FeCo-based nanocrystalline alloys

Temperature dependence of initial permeability (μi-T curves) for as-quenched and annealed (Fe0.5Co0.5)73.5Si13.5B9Cu1M3 (M=Nb, Mo) alloys were investigated. The Curie temperature of Mo-alloy is decreased by about 5 °C compared with Nb-alloy. Although room-temperature μi of Mo-alloy was lower than that of Nb-alloy when nanocrystallized in air, the more stable value of μi and improved high-temperature soft magnetic properties was observed. The reason for the evolution of μi at elevated temperature was also analyzed.