Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1296747 | Solid State Ionics | 2010 | 4 Pages |
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.