THE CU-BI-S SYSTEM - RESULTS FROM LOW-TEMPERATURE EXPERIMENTS

Low-temperature experiments in the 'dry' ternary Cu-Bi-S system, condu cted by using sulphidation methods down to 120-degrees-C produced a ne w metastable solid solution series Cu10Bi2S13-Cu5Bi2S8 at 178-degrees- C, coexisting with CuS. This transformed slowly at 190-200-degrees-C t o an assemblage of either CuS-(Cu,Bi)8S9 or CuS-Bi2S3 or both, dependi ng on available sulphur. Sulphidation experiments on Cu3BiS3 Similarly revealed a solid solution range for the phase (Cu,Bi)8S9 of up to Cu/ Bi = 3/2 at 178-190-degrees-C, and a lower stability limit of 138-degr ees-C. Isothermal sections of the system were constructed at 200 and 3 00-degrees-C, based on the new information collected but excluding the metastable series.