A technique has been developed to measure thermodynamic activities of individual components in liquid-metal mixtures at elevated temperatures. This method utilizes mass-spectrometric detection of beams from multiple Knudsen-cell sources to determine individually the partial pressure of each species over an alloy at the same time as corresponding pure-component vapor pressures. Such a technique is unique in that virtually all other previous thermodynamic methods used for chemical activities in liquid-metal mixtures involve the measurement of a single-component activity, or of relative activities, and require application of the Gibbs-Duhem equation to generate complete activities for both species. Results are reported for (copper + tin) at 1473 K over the entire composition range; not only are the results in good agreement with literature values, but they satisfy a thermodynamic consistency check which cannot be performed on any previous set.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Physical and Theoretical Chemistry