摘要
Se-90 at.%Te and Pb 1-x Sn x Se (x = 0, 0.1, 0.2, 0.3) alloys are important thermoelectric elements. Ni is commonly used as a diffusion barrier layer in contact with thermoelectric elements. The interfacial reactions in the Ni/Se-90 at.%Te and Ni/Pb 1-x Sn x Se (x = 0, 0.1, 0.2, 0.3) couples reacted at 500 °C are examined to study the reaction phase formation and microstructural evolution at the reaction zones. In the solid Ni/liquid Se-90 at.%Te couples reacted at 500 °C, two reaction phase layers, Ni 3 Te 2 and NiTe 2-x , are formed at the contact interface. Dendritic (SeTe) and needle-shaped NiTe 2-x precipitates are found on the thermoelectric side, showing the reaction path is Ni/Ni 3 Te 2 /NiTe 2-x /liquid (SeTe) + NiTe 2-x /liquid Se-90 at.%Te. In the solid Ni/solid Pb 1-x Sn x Se couples reacted at 500 °C, the Ni 3 Pb 2 Se 2 ternary phase is the primary reaction product, regardless of the Sn solubility. Doping of Sn in the Pb 1-x Sn x Se alloys (x ≥ 0.1) causes additional phase formation of Ni 5.62 SnSe 2 , Ni–Sn, and PbSe, giving rise to an interlarded multilayer structure at the reaction zones. The phase formation in the two reaction couples is rationalized by the dominant diffusion species of Ni. The related phase diagrams are assessed and used for illustrating the above-mentioned interfacial reactions.