Thermodynamics of the liquid Co-Cu system and calculation of phase diagram

Knudsen-cell mass spectrometric measurements have been carried out in the liquid phase of the Co-Cu system in the concentration range 25.0 to 85.9 at. % Cu in the temperature range 1347 to 1587 degrees C. The molar excess Gibbs energy, enthalpy and entropy of mixing, as well as the thermodynamic activities of components in the liquid Co-Cu system were determined using the composition and temperature dependence of the ratio of intensities of Co-59 and (CU)-C-63 ions. The results show that a sub-regular solution model would fit measured data well (2-parameter thermodynamically adapted power (TAP) series: C-n(H) in J.mol(-1); C-1(H)= 35,961, C-2(H) = -5573.2; C-n(S) in J.mol(-1.K-1); C-1(s) = 5.54, C-2(s) = -3.35), A special experiment verified solid-liquid phase equilibrium at 1327 degrees C and the phase diagram was calculated.