摘要
Ag 2 Se is a prominent thermoelectric material and Sn is a primary constituent element of joining alloys. The interfacial reactions in the Sn/Ag 2 Se couples at 550 °C, 400 °C and 250 °C are examined for various reaction times between 5 and 120 min. To provide fundamental understanding, the phase equilibria isothermal sections of the ternary Ag-Se-Sn system are also determined. The respective isothermal sections are proposed based on limited ternary experimental results, Ag-Se-Sn phase equilibria studies and the phase diagrams of its constituent binary systems. The reaction layers are parallel to Ag 2 Se substrate and grow thicker with longer reaction times and higher temperatures. Besides a thin SeSn phase layer, a thick ternary Ag 8 Se 6 Sn phase is observed in the reacted Sn/Ag 2 Se couples at all temperatures. Ag concentration decreases in the reaction path from Ag 2 Se side towards molten Sn. Hence, excess Ag is dissolved in the liquid phase and ε-Ag 3 Sn phase precipitates when the couple is removed from the furnace. The determined reaction path is liquid/SeSn/Ag 8 Se 6 Sn/Ag 2 Se for all temperatures.