Systematic aspects of the high-temperature thermochemistry of binary alloys and related compounds

Abstract

In order to obtain reliable information on the high- temperature thermodynamics of binary alloys and related compounds, the modern investigator has a range of different experimental methods at his disposal: vapor pressure measurements, the emf technique, solubility measurements, and high-temperature reaction calorimetry. It is now more than 40 years since we first analyzed these prob-lems in some detail. We recognized, of course, that reaction calorimetry alone cannot provide a complete picture of the thermodynamics of any system. On the other hand, we also knew that the en-thalpy contributions to the excess Gibbs energies of alloys usually outweigh the corresponding en-tropy terms. We concluded that, among these various experimental methods, high- temperature reaction calorimetry should be the most useful approach in any attempt to gain systematic thermo-dynamic information on alloy systems. We accordingly decided to pursue a program of research cen-tered on alloy high- temperature thermochemistry. A review is presented of the development of the modern high- temperature reaction calorimeter and of the application of calorimetric measurements to a wide range of binary alloy systems and related compounds.