The hysteresis properties analysis of Fe-4 wt% Si prepared by high purity metallurgy

An investigation on the improvement in hysteresis properties of high purity Fe-4 wt% Si prepared by cold crucible levitation melting was presented compared with a Fe-0.1 wt% C- 4 wt% Si alloy formed by the identical process. The results showed that thin elongated carbon compounds were precipitated in both grains and grain boundaries of Fe-0.1 wt% C- 4 wt% Si sample observed by means of Kerr effect microscopy and STEM, leading to an apparent degradation in coercivity, permeability and hysteresis loss. With regard to hysteresis loss in Fe-4 wt% Si, it increases linearly with the increase of maximum magnetic flux density below 1.4 T, whereas for Fe-0.1 wt% C- 4 wt% Si, it behaves nonlinearly even at low maximum magnetic flux density and rises sharply with the increase of maximum magnetic flux density. Additionally, the precipitated carbon compounds in the grain boundaries change the morphology of the grain boundaries.