Fe-B-P-Cu nanocrystalline soft magnetic alloys with high Bs

The effects of the addition of Cu on the crystallization processes, nanostructures and soft magnetic properties for the Fe80.8-84.8B8-10P6-8Cu1.2 alloys were investigated. The Fe-B-P-Cu alloys show two separated distinct exothermic peaks upon heating due to the addition of Cu. Furthermore, the interval temperature between each one for the Fe82.8B9P7Cu1.2 alloy is 103 K, and the first and second exothermic peaks result from the phase transition from amorphous to alpha-Fe and then to Fe-3(B,P), respectively. A uniform nanocrystalline structure composed of alpha-Fe grains with a 17 nmdiameter was realized by annealing just above the first exothermic peak, and this nanocrystalline alloy exhibits high B-s of 1.70 T and low H-c of 4.9 A/m. Therefore, the nanocrystalline Fe-B-P-Cu soft magnetic alloy with high Bs and low Hc has a large industrial advantage due to miniaturization, high efficiency and low material cost of electric devices. (C) 2010 Elsevier B.V. All rights reserved.