Abstract
The dehydration and the superprotonic transition behavior of Cs0.75Rb0.25H2PO4 have been investigated via thermogravimetry and differential thermal analysis. To enable measurements under the high water partial pressures required, a high humidity system (pH2O = 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 Cs0.75Rb0.25H2PO4 is 231 °C, slightly higher than that of CsH2PO4. In contrast, dehydration of Cs0.75Rb0.25H2PO4 under pH2O = 0.35 atm occurs at 265 °C, a somewhat lower temperature than that at which CsH2PO4 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.
Original language | English (US) |
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Pages (from-to) | 193-196 |
Number of pages | 4 |
Journal | Solid State Ionics |
Volume | 181 |
Issue number | 3-4 |
DOIs | |
State | Published - Feb 24 2010 |
Funding
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.
Keywords
- Cesium dihydrogen phosphate
- Cesium rubidium dihydrogen phosphate
- Dehydration
- Rubidium dihydrogen phosphate
- Superprotonic transition
- Thermogravimetric and differential thermal analysis
ASJC Scopus subject areas
- General Chemistry
- General Materials Science
- Condensed Matter Physics