Thermal Properties of Rare-Earth Monosilicates for EBC on Si-Based Ceramic Composites
| Autor: | Niranjan Patra, William E. Lee, Daniel Doni Jayaseelan, Denis Horlait, Nasrin Al Nasiri |
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| Přispěvatelé: | Rolls-Royce Plc |
| Rok vydání: | 2015 |
| Předmět: |
Technology
Materials science Scanning electron microscope Materials Science SIC/SIC COMPOSITES Mullite ENVIRONMENTAL BARRIER COATINGS 02 engineering and technology Ceramic matrix composite Thermal diffusivity 01 natural sciences Heat capacity Thermal expansion 0103 physical sciences Materials Chemistry CRYSTAL-STRUCTURE MULLITE Ceramic Composite material 0912 Materials Engineering TEMPERATURE CONDUCTIVITY Materials 010302 applied physics Science & Technology CORROSION 021001 nanoscience & nanotechnology Microstructure visual_art X-RAY Ceramics and Composites visual_art.visual_art_medium OXIDATION BEHAVIOR 0210 nano-technology Materials Science Ceramics RESISTANCE 0913 Mechanical Engineering |
| Zdroj: | Journal of the American Ceramic Society. 99:589-596 |
| ISSN: | 0002-7820 |
| DOI: | 10.1111/jace.13982 |
| Popis: | Rare-earth (RE) monosilicates are promising candidates as environmental barrier coating (EBC) materials for ceramic matrix composites for aerospace applications. Five rare-earth monosilicate materials have been investigated: Y2SiO5, Gd2SiO5, Er2SiO5, Yb2SiO5, and Lu2SiO5 produced from RE oxides and silica starting materials pressed and sintered at 1580°C under flowing air. Relative densities above 94% were obtained for all samples and ceramics were made containing 85–100 wt% of the RE monosilicate according to X-ray diffraction (XRD) with RE disilicates as the second phase in the Gd, Yb, and Lu silicate systems. Microstructures were characterized using scanning electron microscopy and XRD, and thermal properties measured including specific heat, thermal expansion, and thermal diffusivity. For the first time, specific heat capacity values are reported for the monosilicates [0.45–0.69 J·(g·K)−1]. Thermal expansion coefficients (TECs) of the dense samples ranged between 5.9 and 10.3 × 10−6 K−1 measured for 473 to 1473 K. All EBCs have low thermal conductivities [1.8 W·(m·K)−1 or less] making them excellent EBC insulators. |
| Databáze: | OpenAIRE |
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