Thermodynamic properties of solid solutions—I vapor pressures of cadmium over alpha silver-cadmium alloys

Abstract

A new method of measurement of partial vapor pressures over solid alloys has been developed. Solid alloys are formed at elevated temperatures from pure components—one of them being present in vapor form at constant partial pressure—until equilibrium with vapor is reached. The volatile element is maintained at constant pressure by keeping the pure volatile element in liquid form at constant temperature at the low-temperature end of the reaction vessel. Partial vapour pressures of cadmium were measured in the whole alpha field for the Ag-Cd system. The partial heats and entropy of solution of cadmium in silver show abrupt changes at about 4.1, 8.33, 25 and 33.3 at. per cent Cd. These changes are due to changes in ordering.