Microstructure and magnetic properties of (Mn54Al46)98C2 magnets fabricated by liquid-phase sintering with the Mn65Ga35 as an additive

MnAl(C) alloys are widely considered as potential candidates of rare earth-free permanent magnets. Fabrication of MnAl(C) magnets remains an intensive research topic. In this work, liquid-phase sintering is primarily explored to prepare MnAl(C) magnets by sintering (Mn₅₄Al₄₆)₉₈C₂ with Mn₆₅Ga₃₅ as an additive. The sintering temperature of 1273 K ensures the Mn₆₅Ga₃₅ in liquid-state and (Mn₅₄Al₄₆)₉₈C₂ in solid-state. The liquid-phase sintering leads to a noticeable densification effect on the magnets, in which the internal porosity is significantly reduced. As the weight percentage of Mn₆₅Ga₃₅ increases from 0 wt.% to 40 wt.%, the remanence magnetization μ₀M_r increases from 1.44 kGs to 1.83 kGs, the coercivity H_c increases from 1.08 kOe to 1.52 kOe, and the energy product (BH)_max increases from 0.25 MGOe to 0.45 MGOe. The H_c increase is explained based on the nucleation model. This work might provide a possible approach to fabricate MnAl(C) magnets.