Influence of Chromium Content on Microstructure and Magnetic Properties of Fe-Based Nanocrystalline Alloy Powders

Abstract

Fe-based nanocrystalline alloy powders Fe₇₇Cu₁Nb₃Si_5.7B_13.3-xCr_x (x = 0, 0.5, 1.0, 1.5, 2.0 at%) was produced by our own unique technology atomization process “Spinning Water Atomization Process (SWAP^Ⓡ)”. The broad peak of amorphous state was retained for up to chromium content 1.5% in above mentioned composition. The increase in coercive force with heat treatment was suppressed with adding chromium content. Additionally, the rate of rise the magnetic flux density due to nanocrystallization from the amorphous state showed a tendency to increase with adding chromium content. The Fe₇₇Cu₁Nb₃Si_5.7B_11.8Cr_1.5 nanocrystalline powder showed Hc = 46.2 A/m and Bs = 1.34 T. The Fe₇₇Cu₁Nb₃Si_5.7B_11.8Cr_1.5 powder exhibited approximately 7% increase in magnetic flux density and 24% decrease in core loss at 1 MHz at Bm = 0.02 T compared to a commercial (Fe_0.97Cr_0.03)₇₆(Si_0.5B_0.5)₂₂C₂ amorphous powder.