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High temperature conductivity of potassium-beta(double prime)-aluminaPotassium beta(double prime)-alumina (BDPA) single crystals have been reported by several groups to leave higher ionic conductivity than sodium BDPA crystals at room temperature, and similar conductivities are obtained at temperatures up to 600-700 K. Potassium BDPA ceramics have been reported to have significantly poorer conductivities than those of sodium BDPA ceramics, but conductivity measurements at temperatures above 625 K have not been reported. In this study, K(+)-BDPA ceramics were prepared from Na(+)-BDPA ceramic using a modified version of the exchange reaction with KCl vapor reported by Crosbie and Tennenhouse (1982), and the conductivity has been measured in K vapor at temperatures up to 1223 K, using the method of Cole et al. (1979). The results indicate reasonable agreement with earlier data on K(+)-BDPA ceramic measured in a liquid K cell, but show that the K(+)-BDPA ceramic's conductivity approaches that of Na(+)-BDPA ceramic at higher temperatures, being within a factor of four at 700 K and 60 percent of the conductivity of Na(+)-BDPA at T over 1000 K. Both four-probe dc conductivity and four probe ac impedance measurements were used to characterize the conductivity. A rather abrupt change in the grain boundary resistance suggesting a possible phase change in the intergranular material, potassium aluminate, is seen in the ac impedance behavior.
Document ID
19930062462
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Williams, R. M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Jeffries-Nakamura, B.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Underwood, M. L.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Ryan, M. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
O'Connor, D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Kikkert, S.
(JPL Pasadena, CA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Solid State Ionics
Issue: 53-5
ISSN: 0167-2738
Subject Category
Nonmetallic Materials
Accession Number
93A46459
Distribution Limits
Public
Copyright
Other

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