Microstructure features of high performance soft magnetic alloy Fe-3 wt.% Si prepared by metal injection molding

Abstract

The effects of sintering parameters and microstructure features on magnetic properties of Fe-3 wt.% Si alloy prepared by metal injection molding (MIM) was investigated in this study. The sample with high density, the saturation induction (Bs) of 2.0 T, maximum permeability (μmax) of 25 mH/m, coercivity of 22.4 A/m was obtained at 1300 °C for 4 h in hydrogen atmosphere, and the properties of which are close to that of high silicon steel. The microstructure, impurities of C and O, distribution of grain boundary angles and magnetic domain of the sintered alloys were analyzed in correlation with the magnetic properties. It is found that a suitable large grain size of about 300 μm and large grain boundary angles distributed in the range of 30°–60° are beneficial to soft magnetic properties. Moreover, uniform and broad magnetic domains also play an important role in preparation of high performance soft magnetic materials.