[1] | Vassiliev V., Weiping G. Electrochemical Cells with the Liquid Electrolyte in the Study of Semiconductor, Metallic and Oxide Systems. Chapter in the book “Electrochemical cells”. — Intech, Edited by Yan Shao Janeza Trdine 9, 51000 Rijeca, Croatia, 2012. — 31 p. Knowledge of thermodynamic properties and phase diagrams of binary, ternary and many component systems is necessary for solving materials science problems and for designing new products and technologies fitted to actual needs. A rational study of equilibria among phases and of the given system thermodynamic properties leads not only to discovery unknown phases long before they can create practical problems but also to determination of phase thermodynamic stability, homogeneity domain boundaries, and finally to elaboration of an analytical description of the system by using thermodynamic models which are based on the dependency of phase Gibbs energies on such parameters as temperature, concentration and pressure. Experimental studies are the information primary resource for thermodynamic properties and phase diagrams of all systems. The EMF method is one of the most important methods of the physico-chemical analysis. One peculiarity of the EMF is its proportionality to the chemical potential of one of the system components. Improving the accuracy and reproducibility of measurements leads to the increase of the quality and quantity of information about the system. Values of the chemical potential as a function of temperature and composition (T, xi) acquired with uncertainties of ±500 J/mol (especially in a narrow temperature range) give only rough estimates of partial entropy and enthalpy of the components. An accuracy improvement in determining of the chemical potential up to ±10-50 J/mol not only leads to the various thermodynamic properties of the system (partial entropies and enthalpies of components, phase enthalpies of transformation, partial enthalpies at infinite dilution, thermal capacities (Сp), but also gives a possibility to study the diagram of phases in detail (liquidus and solidus, miscibility gaps, invariant points, stoichiometry deviations, ordering, etc...) We showed the universality and self-sufficiency of the method for the systems which were studied. EMF remains one of the most important methods in metallurgical thermodynamics. [ DOI ] |