Interfacial Reactivity of the Filled Skutterudite Smy(FexNi1−x)4Sb12 in Contact with Liquid In-Based Alloys and Sn

Abstract

The study of the wettability of thermoelectric materials, as well as the search for the most proper brazing alloys, is of the maximum importance to get one step closer to the realization of a thermoelectric device. In this work, a wettability study of the filled skutterudite Smy(FexNi1−x)4Sb12 by Sn and In-based alloys is presented. Samples, having both p- and n- characters were prepared by the conventional melting-quenching-annealing technique and subsequently densified by spark plasma sintering (SPS). Afterward, wettability tests were performed by the sessile drop method at 773 K for 20 min. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses performed on the cross-section of the solidified drops suggest quite a complicated scenario due to the coexistence and the interaction of a large number of different elements in each analyzed system. Indeed, the indication of a strong reaction of In-based alloys with skutterudite, accompanied by the formation of the InSb intermetallic compound, is clear; on the contrary, Sn exhibits a milder reactivity, and thus, a more promising behavior, being its appreciable wettability, whilst coupled to a limited reactivity.

Additive Manufacturing of Thermoelectrics: Emerging Trends and Outlook

“…93 The good wettability of Ni also allows it to be used as a metallization layer. 94 Obtaining a high solid loading can only be realized with a well-dispersed slurry. Solid loading refers to the volume (or weight) percentage of powders in the powder-polymer system.…”

“…However, as inorganic TE materials have relatively poor wettability with solder materials, , Au–Cu alloys are commonly used braze due to its relatively low eutectic temperature, enhancing the wettability of the TE legs to the electrode . The good wettability of Ni also allows it to be used as a metallization layer …”