Partial Thermodynamic Properties of gamma-(Ni,Pt)3Al in the Ni-Al-Pt System (Preprint)
CASE WESTERN RESERVE UNIV CLEVELAND OH
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A series of measurements were made to determine how Pt influences the partial thermodynamic properties of Al and Ni in gamma-Ni,Pt3Al and liquid in the Ni-Al-Pt system. The activities of Al and Ni were measured by the vapor pressure technique with a multiple effusion-cell vapor source coupled to a mass spectrometer multi-cell KEMS. For a consistent XAl 0.24, adding Pt, from XPt 0.02 to 0.25, reduces alphaAl almost an order of magnitude, from about 2x10-4 to 2x10-5, at 1560K. This occurred with a consistent delta-mHAl of -203 or- 10 kJmol-1 and the decrease in alphaAl was due to an increase in delta-mSAl, from -60 to -40 Jmol-1K-1 with a decrease in the NiPt ratio.
- Metallurgy and Metallography