THERMODYNAMIC MIXING FUNCTIONS AND PHASE-EQUILIBRIA IN THE NICKEL-CHROMIUM SYSTEM BY HIGH-TEMPERATURE KNUDSEN CELL MASS-SPECTROMETRY

Thermodynamic excess functions of nickel-chromium alloys in the body-c entered cubic (bcc) phase have been investigated by computer-aided Knu dsen cell mass spectrometry in the temperature range of 1300 to 1650 K . Activities, as well as molar excess Gibbs energies, enthalpies, and entropies, were obtained from the ion intensities as a function of com position by fitting to a subregular solution model [2-parameter thermo dynamically adapted power (TAP) series: C-n(H) in J/mol, C-1(H) = 3900 , C-2(H) = 44,610; C-n(H) in J/mol.K, C-1(S) = 9.71, C-2(S) = 13.52]. Based upon these data, the phase diagram has been recalculated.