Rapid microwave sintering of zinc oxide-based varistor ceramics
| Autor: | Kirill I. Rybakov, S. V. Egorov, V. V. Kholoptsev, Yu. V. Bykov, E.Ye. Rostokina, A. A. Sorokin, A. G. Eremeev, Stanislav Balabanov, I. V. Plotnikov |
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| Rok vydání: | 2021 |
| Předmět: |
010302 applied physics
Materials science Sintering chemistry.chemical_element 02 engineering and technology Zinc 021001 nanoscience & nanotechnology 01 natural sciences Instability Isothermal process law.invention Varistor ceramics chemistry law Microwave sintering Gyrotron 0103 physical sciences Materials Chemistry Ceramics and Composites Composite material 0210 nano-technology Microwave |
| Zdroj: | Journal of the European Ceramic Society. 41:6508-6515 |
| ISSN: | 0955-2219 |
| DOI: | 10.1016/j.jeurceramsoc.2021.06.028 |
| Popis: | Samples of ZnO + Bi2O3 + Sb2O3 varistor ceramics were microwave sintered using gyrotron systems operating at a frequency of 24 GHz. The microwave power was automatically regulated to implement heating at a constant heating rate of 10–130 °C/min up to a temperature of 1100–1300 °C with no isothermal hold. The final sintered density of the samples was 95–96 % of the theoretical value. Manifestations of the thermal instability associated with the liquid phase formation were observed at a temperature of about 600 °C. The estimated volumetrically absorbed power density at the onset of instability was ≥20 W/cm3, and the temperature difference measured between the center and periphery of the samples reached 200 °C. Correlation has been revealed between the thermal instability occurrence and the shift of densification curves towards lower temperatures. A mechanism underlying enhanced densification in electromagnetic field-assisted sintering processes is suggested. |
| Databáze: | OpenAIRE |
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