Abstract
Thermoelectric devices convert directly heat and electricity and have gained tremendous research efforts. Usually, there are numerous joints in thermoelectric devices. Interfacial reactions at the joints are crucial to the reliability of devices. This study examines the interfacial reactions in the Ni/Sb and Ni/CoSb3 couples reacted at 723 K and Ni/Te and Ni/Ag2Te couples at 473 K. Three reaction phases, Ni5Sb2, NiSb and NiSb2, are found in the Ni/Sb couples. In the Ni/CoSb3 couples, the reaction path is Ni/Ni5Sb2/(Co,Ni)Sb/ CoSb3. Nickel is the fastest diffusion species, and the growth front is at the (Co,Ni)Sb/CoSb3 interface. A Ni3Te2 reaction layer is found in the Ni/Te couples reacted at 473K. Two reaction regions are observed in the Ni/Ag2Te couple reacted at 473K for 24 hours. A continuous layer is formed adjacent to the Ni substrate, and is likely the Ag7Ni2Te phase. The other reaction region is a two-phase finger-type mixture.