The phase system Cu-Pd-S at 900, 725, 550 and 400 degree C.

The condensed Cu-Pd-S system was studied by means of dry syntheses from elements in evacuated silica glass tubes at 900 degrees, 725 degrees, 550 degrees and 400 degrees C. At 900 degrees C the system contains Cu2-xS (with up to 0.7 at.% Pd), PdS, a broad sulfide melt field and continuous Cu-Pd alloy. At 725 degrees the melt field breaks up into 2 melts and Pd4S appears. No melt was found at 550 degrees C. At 550 degrees and 400 degrees C the alloy field is split, containing beta CuPd which dissolves up to 2.6 at.% S. At these temperatures, the system is dominated by Cu2-xS (traces of Pd), Pd4S and Pd2.2S (UP to 15-16.5 at.% S, respectively), PdS (less than or equal to 1at.% Cu, highest at 550 degrees C) and PdS2. With exception of PdS2 these phases are known as minerals. Solubility of Cu in Pd2.2S and Pd4S is an important temperature indicator.