Synthesis of highly dense spark plasma sintered magnetocaloric Ni-Mn-Sn alloys from melt-spun ribbons

Abstract In this work, polycrystalline melt-spun ribbons of the magnetocaloric Ni50Mn37Sn13 Heusler alloy were used as precursor material in order to fabricate a nearly 98 % dense piece by means of spark plasma sintering. SEM and XRD data show that consolidation was achieved through ribbons surfaces preserving the structural and microstructural properties. Structural transformation temperatures and magnetic properties for the as-sintered SPS sample remained similar to the precursor. A moderate shifting in the martensitic transformation to higher temperatures (8 K) for the sintered piece was observed. Furthermore, higher values of maximum entropy change were calculated for the sintered sample (10.1 Jkg-1K-1 at 5 T), which basically doubles that of the precursor ribbons.