Microstructural and core loss behaviors of addictive Fe-17 at% P based on Fe-3.5 wt% Si alloys in powder injection molding

Highlights: • Effect of Fe-17 at% P on the magnetic properties of Fe-Si alloys was analyzed. • The feedstocks were prepared based on the processing optimization. • Microstructure, relative density, and impurities of the samples were analyzed. • The core loss, resistivity, and magnetic induction were enhanced with Fe-17 at% P. • Fe₃P phase did not show the effect of reducing the loss as an insulation layer. This study investigated Fe-17 at% P addition effects on the magnetic properties of Fe-3.5 wt% Si alloys to enhance the electrical resistivity and core loss in powder injection molding. Considering the lowest melting point for 17 at% of P in the Fe-P phase diagram, the effect of P in Fe-3.5 wt% Si was analyzed by adding Fe-17 at% P from 0 to 12 wt% with 4 wt% increments. The feedstocks were prepared based on the processing optimization with respect to the critical solid loading, mixing homogeneity, and binder decomposition. The microstructure; relative density; electrical resistivity; and C, O, N, and S impurities of the sintered alloys were analyzed in correlation with the magnetic properties. The magnetic induction (B₅₀₀₀), maximum permeability, coercivity at 400 Hz and core loss in the frequency range from 50 to 1000 Hz at 1 T were analyzed. The higher magnetic induction and the lower eddy current loss with increasing Fe-17 at% P addition were induced by the higher relative density and electrical resistivity, respectively.