Studies on Bismuth Alloys. II. Distribution of Small Additions of Cu, Ag, or Au Between Solid and Liquid Phases in Bi-Cu, Bi-Ag, and Bi-Au

The distribution of small amounts of radioactive Cu, Ag, and Au between precipitates of these elements and their solutions in bismuth was investigated at different temperatures by sampling the liquid. In all cases the Doerner-Hoskins law was obeyed. Approximate distribution ratios were calculated and plotted against 1/T. Extrapolation to the melting temperature of the major component X in these Bi-X-Y systems yields values which compare well with the distribution constants obtained either from the binary X-Y phase diagrams or with those calculated from thermodynamic data. The data support solid solution formation as the mechanism of coprecipitation. This investigation also suggests a new method of obtaining significant portions of solidus curves.