摘要
Sb 2 Te 3 is an important thermoelectric material. Co is a potential diffusion barrier. This study examined the electroplated Co/Sb 2 Te 3 interfacial reactions at 300 °C, 400 °C and 500 °C. To provide fundamental information and for better understanding the reaction paths, the Co-Sb-Te phase equilibria isothermal sections at these three temperatures are proposed. No ternary compound is found. The 400 °C isothermal section contains (Co), (Sb), (Te), β-CoSb, β-Co 1−x Te, CoSb 3 , δ-(Sb 2 Te), γ-(SbTe), Sb 2 Te 3 and a continuous solid solution γ-Co(Sb,Te) 2 . At 500 °C, except for Te being molten, the phase relationships are similar to those at 400 °C. At 300 °C, although γ-CoSb 2 and γ-CoTe 2 have very significant mutual solubilities, they are two separate phases and do not form a continuous solid solution. In the Co/Sb 2 Te 3 couple reacted at 300 °C, only one reaction phase, γ-CoTe 2 with Sb solubility, is formed. Similar results are found in the Co/Sb 2 Te 3 couple reacted 400 °C, and the reaction phase is the continuous solid solution γ-Co(Sb,Te) 2 . Two reaction phases, β-Co 1-x Te and γ-Co(Sb,Te) 2 , are found in the couple reacted at 500 °C. The compositional ratio of Sb/Te in the reaction phase remained at 2/3 indicates that Co is the dominating diffusion species. The reaction phases are formed rapidly by Co penetration into the Sb 2 Te 3 substrate. A peculiar phenomenon was found with the reaction layer that formed on the side of Co that was not in direct contact with the Sb 2 Te 3 substrate which will be further investigated.