Improvement of stability in a Mg2Si-based thermoelectric single-leg device via Mg50Si15Ni50 barrier

In this study we investigated the nature and stability of the interfaces between Mg 2.05 Si 0.98 Bi 0.02 as the TE material and Ni and Mg 50 Si 15 Ni 50 as barriers. Single-leg devices of Ni/TE/Ni and Mg 50 Si 15 Ni 50 /TE/Mg 50 Si 15 Ni 50 were prepared by the SPS process in one step and were then subjected to different aging conditions. Using Mg 50 Si 15 Ni 50 as barrier provided a more stable interface with no evidence of an interaction layer. This contrasted with the case when Ni was used as a barrier. The efficiency, η , and the power output, P out , were higher when Mg 50 Si 15 Ni 50 was used as a barrier. The Ni/TE/Ni and Mg 50 Si 15 Ni 50 /TE/Mg 50 Si 15 Ni 50 devices were aged at 673 K for up to 480 h under vacuum and an Mg vapor. For the Mg 50 Si 15 Ni 50 /TE/Mg 50 Si 15 Ni 50 device, the Seebeck coefficient, the efficiency, and power output showed no change with aging time when aging was carried out under in an Mg vapor. The present observations showed that a stable interface can be attained when Mg 50 Si 15 Ni 50 is used as a barrier for the Mg 2.05 Si 0.98 Bi 0.02 TE material .