Study on the interfacial stability of p-type Ti/CeyFexCo4-xSb12 thermoelectric joints at high temperature

The interfacial stability of thermoelectric (TE) joints is among the key issues determining the durability of thermoelectric generators (TEGs) in practical operation. For skutterudite (SKD) based TEGs, the inter-diffusion between the metal electrode and the SKD material at high temperature plays a vital role on the interfacial stability of the joints. In this work, we report the evolution of the interfacial microstructure and the interfacial contact resistivity for a series of p-type SKD TE joints (Ti/CeyFexCo4-xSb12, x = 1.5-4, y = 0.35-1) at high temperature. The growth of the intermetallic compound (IMC) layers at the interface of all the joints was found to be controlled by the diffusion process. In contrast to the binary Ti/CoSb3 joints, the growth of the interfacial IMC layers in the p-type Ti/CeyFexCo4-xSb12 joints was considerably depressed. Moreover, no brittle TiCoSb phase was formed at the interface of the p-type joints, which resulted in good stability of the interfacial contact resistivity at high temperature. Related mechanisms were discussed. (C) 2016 Elsevier B.V. All rights reserved.