Exploratory studies of the Cu–Pd–Se system at 650°C, 550°C, 400°C, and 300°C

Abstract

The condensed-phase system Cu–Pd–Se was investigated by means of dry syntheses from elements in evacuated silica glass tubes at 650 °C, 550 °C, 400 °C, and 300 °C. Synthetized phases were analysed by electron microprobe and textural studies in polished sections. At 650 °C an extensive selenide liquid field covers central portions of the system, coexisting with a limited choice of Pd selenides, Cu 2– x Se, alloys, and a (Cu,Pd)Se 2 solid solution. The selenide melt recedes to the Pd side of the system at 550 °C and its remnants persist at 400 °C. At the lower temperature, the gamut of Pd selenides becomes richer, and especially Pd 4 Se and Pd 17 Se 15 display significant solubility of Cu. The composition range of (Cu,Pd)Se 2 broadens and moves towards Cu-richer compositions as temperature decreases; CuSe and CuSe 2 appear at 300 °C. The synthetic analogue of jagueite, Cu 2 Pd 3 Se 4 , is present at 400 °C and 300 °C, at Se concentrations above the Cu 2– x Se–Pd 17 Se 15 line. At all examined temperatures, the individualized CuPd alloy dissolves Se, up to ∼5 at% at low temperatures.