Insights on the phase transitions, stability and conductivity in the Bi2O3-WO3 system
| Autor: | Rudolph M. Erasmus, Sikhumbuzo M. Masina, Caren Billing, David G. Billing |
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| Rok vydání: | 2021 |
| Předmět: |
Arrhenius equation
Phase transition Materials science Annealing (metallurgy) Analytical chemistry Ionic bonding Atmospheric temperature range Conductivity Condensed Matter Physics Electronic Optical and Magnetic Materials symbols.namesake Mechanics of Materials Phase (matter) Materials Chemistry Ceramics and Composites symbols Electrical and Electronic Engineering Raman spectroscopy |
| Zdroj: | Journal of Electroceramics. 46:47-56 |
| ISSN: | 1573-8663 1385-3449 |
| Popis: | Equilibrium phases of the Bi2O3-WO3 system, synthesized using the citrate-gel method with slow cooling, have been systematically investigated for samples with 22–27 mol% WO3. Annealing temperature and content of WO3 were shown to play a significant role in the phases present. Both powder X-ray diffraction and Raman spectroscopy revealed that the room temperature equilibrium phases were 7Bi2O3-WO3 and 7Bi2O3-2WO3, with the latter being dominant. Variable temperature Raman spectroscopy showed that both these phases were present up to 850 °C, with the possible formation of a third unidentified phase at higher temperatures. The ionic conductivities of the mixed-phase materials were between that for the pure 7Bi2O3-WO3 and 7Bi2O3-2WO3 phases and at 700 °C was only about three times lower than that of the pure defect fluorite phase of the 22 mol% WO3 samples. The Arrhenius plots showed no sudden increase in conductivity between 300 and 750 °C providing evidence that no major phase change occurred in this temperature range. |
| Databáze: | OpenAIRE |
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