Ikeda, Ayako and Haile, Sossina M. (2010) Examination of the superprotonic transition and dehydration behavior of Cs_(0.75)Rb_(0.25)H_2PO_4 by thermogravimetric and differential thermal analyses. Solid State Ionics, 181 (3-4). pp. 193-196. ISSN 0167-2738 http://resolver.caltech.edu/CaltechAUTHORS:20100528-075003630
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The dehydration and the superprotonic transition behavior of Cs_(0.75)Rb_(0.25)H_2PO_4 have been investigated via thermogravimetry and differential thermal analysis. To enable measurements under the high water partial pressures required, a high humidity system (p_(H_2O) = 0.02–0.8 atm) capable of weight change detection at 0.7% resolution and thermal events with 0.01 °C resolution was assembled. It has been found that the superprotonic phase transition temperature of Cs_(0.75)Rb_(0.25)H_2PO_4 is 231 °C, slightly higher than that of CsH_2PO_4. In contrast, dehydration of Cs_(0.75)Rb_(0.25)H_2PO_4 under p_(H_2O) = 0.35 atm occurs at 265 °C, a somewhat lower temperature than that at which CsH_2PO_4 undergoes dehydration. Analysis of the temporal evolution of both transformations suggests a mechanism of continuous nucleation of the high temperature phase at a constant nucleation rate combined with three-dimensional growth.
|Additional Information:||© 2009 Elsevier B.V. Received 20 August 2008; revised 26 September 2009; accepted 26 October 2009. Available online 17 November 2009. The authors gratefully acknowledge Mary Louie for providing EDS chemical analysis results. This work has been funded by a Department of Defense MURI award administered by the Army Research Office (W911NF-07-1-0410). Additional support has been provided by the National Science Foundation (DMR-0520565), through the Caltech Center for the Science and Engineering of Materials.|
|Subject Keywords:||Cesium rubidium dihydrogen phosphate; Cesium dihydrogen phosphate; Rubidium dihydrogen phosphate; Dehydration; Superprotonic transition; Thermogravimetric and differential thermal analysis|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||28 May 2010 20:57|
|Last Modified:||26 Dec 2012 12:05|
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