Thermochemistry of the Ni-Hf system -- Intermetallic phases
- Eoetvoes Univ., Budapest (Hungary). Dept. of Physical Chemistry
- Research Centre Juelich (Germany). Inst. for Materials in Energy Systems
The vaporization of alloys of the Ni-Hf system was investigated in the temperature range between 1,200 and 1,650 K by Knudsen effusion mass spectrometry. The different compositions of the 16 alloy samples investigated covered the complete homogeneity range of the Ni-Hf system. The partial pressure of Ni was determined over all samples. The thermodynamic activities of Ni and Hf in the alloys were evaluated from these pressures and by Gibbs-Duhem integration. In addition, Gibbs energies of formation, enthalpies of formation, and entropies of formation resulted for the nine intermetallic phases of the Ni-Hf system. Beside similar thermodynamic data for the evaporation reactions were studied. The data obtained are discussed and a method for distinguishing the congruent melting compounds from the peritectic ones by defining stability factors calculated from the Gibbs energies of formation is suggested.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 413288
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 11 Vol. 27; ISSN MMTAEB; ISSN 1073-5623
- Country of Publication:
- United States
- Language:
- English
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ANNEALING
CHEMICAL COMPOSITION
EMISSION SPECTROSCOPY
FREE ENTHALPY
HAFNIUM ALLOYS
INTERMETALLIC COMPOUNDS
KNUDSEN FLOW
LIQUID METALS
MASS SPECTROSCOPY
NICKEL ALLOYS
PARTIAL PRESSURE
PHASE DIAGRAMS
QUENCHING
SAMPLE PREPARATION
TEMPERATURE DEPENDENCE
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY