Soft magnetic Fe-Si-B-Cu nanocrystalline alloys with high Cu concentrations

High saturation magnetic flux density (B-s) soft magnetic nanocrystalline alloys with good manufacturability were developed in a simple Fe-Si-B-Cu alloy system with high Cu concentrations. The nanocrystalline alloys with high Bs of similar to 1.77 T and low coercivity of similar to 7.1 A m were obtained by annealing the melt-spun Fe-Si-B-Cu alloys containing 1.7-2.0 at% Cu. The high content of Cu facilitates the formation of high-number-density alpha-Fe nuclei with an average grain size of similar to 6 nm pre-existing in the amorphous matrix, which inhibits the excessive growth of the alpha-Fe grains by their competitive growth even during the low-heating-rate annealing, resulting in a fine nanostructure and excellent soft magnetic properties. (C) 2017 Elsevier B.V. All rights reserved.