The system Cu-Rh-S at 900 degrees, 700 degrees, 540 degrees and 500 degrees C

Phase relations in the dry condensed system Cu-Rh-S were determined at 900, 700, 540 and 500 degrees C. At 900 degrees C, the system contains digenite, four rhodium sulfides (Rh17S15, Rh3S4, Rh2S3 and RhS similar to 3), three ternary sulfides (CuRh2S4, CuxRhS3+x and a fibrous sulfide in the range Cu11.9Rh24.6S63.6 - Cu20.4Rh19.8S59.7), Cu-S sulfide melt, and Cu-Rh alloys. At 700 degrees C, the ternary association changes to CuRh2S4, CuRhS3, and CuRhS4. All these phases persist with little change at 540 degrees C. At 500 degrees C, CuS appears, and the number of phases is reduced; only CuRhS4 persists as a ternary phase. Ranges of solid solution for Cu-Rh alloys drop drastically with temperature. The solubility of Cu in Rh sulfides increases moderately as temperature decreases from 900 degrees to 540 degrees C. The solubility of Rh in digenite and Cu-S melt is very limited at all temperatures.