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Comparison of the thermal stability of a. beta. - and. beta. ''-alumina at high pressures. [5 to 50 kb, room temperature to 1400/sup 0/C]

Journal Article · · J. Solid State Chem.; (United States)
The high-pressure thermal stability of Na/sup +/ ..beta..-alumina and magnesium-stabilized Na/sup +/ ..beta..''-alumina was studied from 5 to 50 kb and from room temperature to 1400/sup 0/C. Above 5 kb and 560/sup 0/C, Na/sup +/ ..beta..-alumina decomposes into ..cap alpha..-Al/sub 2/O/sub 3/ and NaAlO/sub 2/. Magnesium-stabilized Na/sup +/ ..beta..''-alumina decomposes at slightly higher temperatures to ..cap alpha..-Al/sub 2/O/sub 3/, MgAl/sub 2/O/sub 4/, and probably NaAlO/sub 2/. Estimates of activation volume and enthalpy support a model for decomposition that depends on cation vacancies and proceeds by sodium diffusion in quasi-liquid conduction planes. 5 figures, 1 table.
Research Organization:
General Electric Co., Schenectady, NY
OSTI ID:
7293280
Journal Information:
J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 20:2; ISSN JSSCB
Country of Publication:
United States
Language:
English