NbCoSn 비정질 분말 전구체를 활용하여 고밀도 /고경도 half-Heusler 계 열전 디스크 제조

초록

NbCoSn-based half-Heusler alloys are promising n-type thermoelectric materials owing to their high power factor and thermal stability. However, conventional processing routes using crystalline precursors from as-cast ingots are associated with elemental segregation and secondary phases, which degrade the thermoelectric performance. In this work, amorphous NbCoSn powders were used as precursors and were consolidated via spark plasma sintering, resulting in dense and homogeneous half-Heusler discs. Compared to samples prepared from crystalline precursors, the amorphous-precursor discs exhibited significantly enhanced properties: a maximum ZT value of approximately 0.35 at 973 K, hardness close to 1085 Hv, and a nanostructured grain microstructure. These improvements are attributed to the suppression of secondary phases and grain refinement induced by the crystallization of the amorphous powders during sintering. The results demonstrate that using amorphous precursors is an effective strategy to enhance the thermoelectric and mechanical performance outcomes simultaneously while reducing both the processing time and cost.

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