COMPUTER-AIDED THERMODYNAMICS OF SOLID TERNARY FE-1-X,(NI0.86CR0.14)XALLOYS BY KNUDSEN CELL MASS-SPECTROMETRY

Knudsen cell mass spectrometry has been employed to investigate thermo dynamically the fee solid ternary Fe-1-x(Ni0.86Cr0.14)(x) alloys. The ''Digital Intensity-Ratio'' (D.I.R.)-method has been applied for the d etermination of the thermodynamic excess properties. Fee solid ternary Fe-1-x(Ni0.86Cr0.14)(x) alloys are characterized by negative molar ex cess Gibbs energies G(E), negative molar excess entropies S-E, and exo thermic molar heats of mixing H-E. At 1673 K the minimum H-E value is -2830 J/mol (28 at.% Fe), the minimum G(E) value is -2390 J/mol (29.5 at .% Fe), and the minimum S-E value is -0.27 J/(mol K) (28 at.% Fe). At 1673 K the thermodynamic activities of Fe show slight negative devi ations from the ideal behavior for alloys with a Fe-content of less th an 70 at .%, and ideal behavior for the Fe-rich alloys (x(Fe)>0.7).