The Sn-rich corner of the system Ni-Pd-Sn: A phase diagram study

The Sn-rich corner (50-100 at.% Sn) of the ternary system Ni-Pd-Sn was studied for two partial isothermal sections at 250 and 500 °C by a combination of powder XRD, optical microscopy and SEM/EDX. The ternary solubility ranges at both temperatures of investigation are found between 3 and 12 at.% Ni for the compounds PdSn4, PdSn3, PdSn2 and PdSn, while the binary phase Ni3Sn4 was found to dissolve up to 33.5 at. Pd. The monoclinic lattice parameters for this phase were studied in detail as function of composition in the entire composition range between Ni3Sn4 and Ni0.7Pd2.3Sn4. DTA experiments were used to explore the ternary phase reactions in the Sn-rich corner, and a total number of six new invariant reactions were identified. A ternary reaction scheme (Scheil diagram) and a liquidus projection are given.