Effect of Si/B ratio on glass-forming ability, phase transitions and magnetic properties in (Fe40Ni40SixByCu1)0.97Nb0.03 alloys

Abstract

The (Fe40Ni40SixByCu1)0.97Nb0.03 (Si/B = 3:1, 2:1, 1:1, 1:2 and 1:3) alloys were fabricated through the melt-spun technique. The effects of Si/B ratio on the glass-forming ability (GFA), phase transitions and soft magnetic properties were investigated. Results showed that when Si/B = 1:1, 1:2 and 1:3, the GFA of the FeNiSiBCuNb alloy is good, and the amorphous structure is homogeneous. We found a phase transition from the amorphous phase to α-Fe (Si) phase and then to γ-(Fe,Ni)Si phase in Si/B = 1:1 alloy by employing a simple heat treatment process. The alloys with Si/B = 1:1 and 1:2 containing a low coercivity of 0.30 A/m and 0.25 A/m domain structures were characterized with magneto-optical Kerr microscope (MOKE) to unveil that the internal stress relief is beneficial to the magnetization process. The three alloys exhibit different crystallization behaviors, and moderate Si can effectively inhibit γ-(FeNi) grains overgrowth.