HTHP 49.1-2, p. 197-210

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Recent studies on thermophysical properties of metallic alloys with PROSPECT – Excess properties to construct a solution model
H. Fukuyama, M. Watanabe and M. Adachi

We have developed the system PROSPECT for measuring thermophysical properties at high temperature. Precise thermophysical measurements provide accurate excess functions, which represent non-ideality of solutions. We use excess functions to discuss solution models on the basis of electronic structure and thermodynamics. Pd-Fe systems show positive excess volume V^E with negative excess Gibbs energy G^E. The phase diagrams of these systems have common features with those of other Pd-X and Pt-X systems (where X is Fe, Ni, Co, or Cu), which means they all have order-disorder transitions. The correlation between V^E and G^E is discussed in terms of the electronic structure of the alloys, and an energy diagram is proposed to understand this correlation. The excess heat capacity Cp^E of Fe-Ni melts is positive over a whole composition range and a wide temperature range. We estimate the temperature dependences of the excess enthalpy H^E and excess entropy S^E of Fe-Ni melts from Cp^E. The Lupis-Elliott rule is satisfied for H^E and S^E with positive Cp^E.

Keywords: thermophysical properties, electromagnetic levitation, density, excess volume, heat capacity, excess heat capacity, modulation calorimetry, binary alloys, liquid metals

Full Text (Open Access)
DOI: 10.32908/hthp.v49.851