Ceramics-Silikáty 64, (1) 35 - 39 (2020) |
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THE EFFECT OF LONG-TERM EXPOSURE TO HIGH TEMPERATURE ATMOSPHERE ON THE MECHANICAL PROPERTIES OF Al₂O₃-BASED CERAMIC MATERIALS
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Hlinčík Tomáš 1, Berka Jan 1,2, Kutzendörfer Jaroslav 3, Hamáček Jiří 3, Sajdl Petr 4
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1 Department of Gaseous and Solid Fuels and Air Protection, University of Chemistry and Technology, Prague (UCT Prague), Technická 5, 1666 28 Prague 6, Czech Republic
2 Centrum Vyzkumu Rez s.r.o., Hlavní 130, 2568 Husinec-Rez, Czech Republic
3 Department of Glass and Ceramics, University of Chemistry and Technology, Prague (UCT Prague), Technická 5, 1666 28 Prague 6, Czech Republic
4 Department of Power Engineering, University of Chemistry and Technology, Prague (UCT Prague), Technická 5, 1666 28 Prague 6, Czech Republic
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Keywords: High-temperature ceramics, Corundum (alumina), Mullite ceramics, Helium, Supercritical water
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Two corundum-based ceramic materials (C799 and C795) and one type of mullite ceramics (C610) have been tested for the production of components of technological circuits working with high-temperature helium and supercritical water. The materials were exposed to an atmosphere of high-temperature helium (900 °C), air (900 °C) and supercritical water (577 °C; 24 MPa) for 1000 hours and subsequently tested for bending strength at temperatures up to 1400 °C. The highest bending strength was exhibited by the corundum ceramics C799 (more than 300 MPa at 25 °C); for a significant decrease in the strength, it was necessary to use temperatures higher than 1000 °C. This material also exhibited relatively good stability during exposure to high-temperature helium, hot air as well as supercritical water; after 1000-hour exposure, its tensile strength decreased by maximally 11 %. Therefore, the pure corundum material has been evaluated as the most suitable among the tested materials for the production of components of the mentioned technological circuits. |
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doi: 10.13168/cs.2019.0046
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