Thermodynamics of liquid binary alloys of the 3d transition metals with metalloids: generalization

Abstract

The optimal assessment of self-consistent thermodynamic properties of liquid binary alloys of the 3d transition metals (Tr  Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) with metalloids (Mt  B, C, Si, Ge) obtained via the compilation from literature of the experimental data for direct measurements of the Gibbs free energies (partial vapour pressure or e.m.f. methods) and the enthalpies of mixing (isoperibolic calorimetry) are presented. On the basis of these data empirical relations were derived. The relations allow the assessment of partial and integral excess entropies of mixing using only concentration dependences within studied range of the enthalpies of mixing and values of melting and boiling temperatures of pure components in a binary system. The relations obtained are well applicable to melts with strong chemical interaction between unlike atoms as well as to melts with sign-variable or positive deviations of the thermodynamic functions from ideality. Empirical calculations carried out for all earlier investigated TrMt systems are in proper agreement with experimental data. Using the relations and calorimetric measured data the assessment of excess entropies of mixing for high temperature and chemically active liquid alloys of the systems TiSi, VSi, CrSi, CrB, CrC, MnB, CaGe, ScGe and TiGe that are absent in reference and periodical literature was carried out.