Abstract
CoSb 3 -based alloys are promising thermoelectric materials, and nickel is commonly used as barrier layer. This study examines interfacial reactions in the Ni/Sb and Ni/CoSb 3 couples reacted at 723 K. Three reaction phases, Ni 5 Sb 2 , NiSb and NiSb 2 , are found in the Ni/Sb couples. In the Ni/CoSb 3 couples, the reaction path is Ni/Ni 5 Sb 2 /(Co,Ni)Sb/CoSb 3 . Nickel is the fastest diffusion species, and the growth front is at the (Co,Ni)Sb/CoSb 3 interface. Co is the second fastest diffusion species, and a Co-rich region is formed at the Ni phase. The reaction layers grow with longer reaction time. Their average growth rates in the Ni/Sb and Ni/CoSb 3 couples reacted for 20 h are 1.1 μm/h and 1.0 μm/h, respectively.