Calculated thermodynamic data and metastable immiscibility in the system SiO/sub 2/--Al/sub 2/O/sub 3/

Journal Article · Sat Jan 01 04:00:00 EST 1977 · J. Am. Ceram. Soc.; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1977.tb15525.x· OSTI ID:6376452

Risbud, S H; Pask, J A

Thermodynamic data on activities, activity coefficients, and free energies of mixing in SiO/sub 2/--Al/sub 2/O/sub 3/ solutions were calculated from the phase diagram. Positive deviations from ideal mixing in the thermodynamic data suggest a tendency for liquid immiscibility in both SiO/sub 2/- and Al/sub 2/O/sub 3/-rich compositions. The calculated data were used to estimate regions of liquid-liquid immiscibility. A calculated metastable liquid miscibility gap with a consolute temperature of approx. = 1540/sup 0/C at a critical composition of approx. = 36 mol % Al/sub 2/O/sub 3/ was considered to be thermodynamically most probable; the gap extended from approx. = 11 to approx. = 49 mol % Al/sub 2/O/sub 3/ at 1100/sup 0/C. SiO/sub 2/-rich glass compositions showed evidence of glass-in-glass phase separation when examined by direct transmission electron microscopy.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 6376452
• Journal Information: J. Am. Ceram. Soc.; (United States), Journal Name: J. Am. Ceram. Soc.; (United States) Vol. 60:9-10; ISSN JACTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
DIAGRAMS
ELECTRON MICROSCOPY
ENERGY LEVELS
ENHANCED RECOVERY
ENTHALPY
EXCITED STATES
FLUID INJECTION
FLUIDS
FUSION HEAT
GLASS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTHERMAL PROCESSES
KINETICS
LIQUIDS
METASTABLE STATES
MICROSCOPY
MINERALS
MISCIBLE-PHASE DISPLACEMENT
MULLITE
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
REACTION KINETICS
SILICON COMPOUNDS
SILICON OXIDES
TEMPERATURE DEPENDENCE
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION HEAT
TRANSMISSION ELECTRON MICROSCOPY