Thermal-mechanical stability of single crystal oxide refractive concentrators for high-temperature solar thermal propulsion
Single crystal oxides such as yttria-stabilized zirconia (Y{sub 2}O{sub 3}-ZrO{sub 2}), yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}, or YAG), magnesium oxide (MgO) and sapphire (Al{sub 2}O{sub 3}) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO{sub 2} laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet and magnesium oxide.
- Research Organization:
- Ohio Aerospace Inst., Cleveland, OH (US)
- OSTI ID:
- 20026752
- Resource Relation:
- Conference: Renewable and advanced energy systems for the 21st Century, Maui, HI (US), 04/11/1999--04/15/1999; Other Information: 1 CD-ROM. Operating system required: Windows i386(tm), i486(tm), Pentium (R) or Pentium Pro, MS Windows 3.1, 95, or NT 3.51, 8 MB RAM; MacIntosh and Power MacIntosh with a 68020 or greater processor, System software version 7.1, 3.5 MB RAM (5 MB for PowerMac) 6 MB available hard-disk space; UNIX; PBD: 1999; Related Information: In: Renewable and advanced energy systems for the 21st century, RAES'99 proceedings, by Hogan, R.; Kim, Y.; Kleis, S.; O'Neal, D.; Tanaka, T. [eds.], [1125] pages.
- Country of Publication:
- United States
- Language:
- English
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