Phase equilibria in the PbO--Al/sub 2/O/sub 3/ system
The use of the Knudsen effusion weight loss technique to measure the equilibrium vapor pressure of PbO in the PbO--Al/sub 2/O/sub 3/ system is described. The pressures are measured in two phase regions of the system to assess the applicability of this system as a packing powder to control the stoichiometry of lead zirconate-titanate ceramics during processing by fixing the PbO pressure in the sintering environment. The need for revision of the current PbO--Al/sub 2/O/sub 3/ phase diagram is demonstrated and the revision is accomplished by calculating the decomposition temperatures of the three intermediate phases. The calculations combine the measured PbO pressures with estimated pressures along the high Al/sub 2/O/sub 3/ liquidus. The liquidus position and pressures are estimated using three approaches: the regular solution, the empirical and the modified ideal solution. The Gibb's free energies of formation of the intermediate phases are determined and the extent of nonstoichiometry is considered.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6515917
- Report Number(s):
- LBL-8219
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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ALUMINIUM OXIDES
PHASE DIAGRAMS
LEAD OXIDES
VAPOR PRESSURE
FREE ENTHALPY
ALUMINIUM COMPOUNDS
CHALCOGENIDES
DIAGRAMS
ENERGY
LEAD COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
360204* - Ceramics
Cermets
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360202 - Ceramics
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