Interaction of Skutterudites with Contact Materials: A Metallurgical Analysis

Abstract

More than hundred diffusion couples between p- and n-type skutterudites and various materials were prepared and interaction zones were investigated after heat treatment at 600 °C for 1100 h. The constitution of reaction/diffusion zones was discussed in terms of: (a) atom site preference in the skutterudite lattice, (b) phase equilibria in multicomponent systems and (c) particularities of the crystal structure of intermediate phases. It could be shown that phase composition and thermo-mechanical properties of bonding can be engineered by chemical substitution. The results obtained allowed the determination of several necessary criteria for the development of chemically and mechanically stable diffusion barriers/couples for skutterudite based thermoelectric (TE) modules.

Challenges and Progress in Contact Development for PbTe‐based Thermoelectrics

“…While phase diagrams are a powerful tool for determining the chemical stability between PbTe and contact layer materials [82,96–102,105] as functions of temperature and chemical composition, their investigation is time‐consuming. As an alternative, high‐throughput experiments [48] of PbTe/contact material combinations at various annealing temperatures and annealing times can give valuable information in less time to evaluate stability conditions of contact materials, as demonstrated in other thermoelectric materials such as skutterudites [113] . To improve the mechanical stability of the bond between PbTe leg and contact layers, CTE matching should be improved.…”

“…As an alternative, high-throughput experiments [48] of PbTe/contact material combinations at various annealing temperatures and annealing times can give valuable information in less time to evaluate stability conditions of contact materials, as demonstrated in other thermoelectric materials such as skutterudites. [113] To improve the mechanical stability of the bond between PbTe leg and contact layers, CTE matching should be improved. While most studies have focused on pure metals as contact layers, new contact layer materials consisting of 2 or more elements with CTE matching with PbTe should be explored in the vast space of alloys and intermetallic compounds.…”