Study on Microstructure and Interfacial Properties of n-Type Segmented Skutterudite/Half-Heusler Thermoelectric Material by Low-Temperature Bonding

Skutterudite (SKD)/Ni-Sn/Half-Heusler (HH) sandwich joining piece was developed and applied to fabricate segmented SKD/HH thermoelectric joints. The microstructure and interfacial properties of SKD/Ni-Sn/HH joints prepared by sintering and electroplating were studied by microstructure observation, aging test, and interface contact resistance test. The results show that the metallized transition layer of HH prepared by electroplating Ni can avoid the formation of intermetallic compounds between Ni and HH, significantly reducing the contact resistance of the joint. The SKD/Ni-Sn/HH joint was well bonded, and high melting point intermetallic compounds are formed at the joint interface before and after aging, resulting in no cracks. The weld microstructure has good thermal stability. After high-temperature aging at 600 °C, the weld microstructure does not undergo severe mutual diffusion with the thermoelectric material. The current flows smoothly through the bonding layer, resulting in low contact resistance. The total contact resistance of the joint before and after aging do not change significantly.