Thermodynamische untersuchung der systeme Kupfer-Gallium, Kupfer-Indium, Kupfer-Germanium und Kupfer-Zinn

Abstract

The partial free enthalpies of formation of α-Cu solid solutions of the systems CuGa, CuIn, CuGe and CuSn, the intermetallic phases β and γ in the CuGa system, ξ and ε in the CuGe system, and β and γ in the CuSn system were determined with the aid of a solid-state galvanic cell of the type ▪ and ▪ The evaluation of the results yielded the complete thermodynamic excess functions of these alloys. After estimating the influence of the lattice distortion energies caused by differences in atomic radii, the bonding contribution to the partial free enthalpy of formation was determined. This contribution is quite large in the systems studied and essentially determines the thermodynamic properties of the α-Cu solid solution under consideration. A correlation of the bonding contribution with the filling of the 4s band of the copper could be shown, and the density of state of the conduction band of the copper could be estimated.