About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
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Symposium
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Coatings to Protect Materials from Extreme Environments
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Presentation Title |
Thermal and Mechanical Properties of Y<sub>3</sub>(Nb<sub>1-x</sub>Ta<sub>x</sub>)O<sub>7</sub> as a Material for Thermal Barrier Coating |
Author(s) |
Janghyeok Pyeon, Dowon Song, Gualin Lyu, Junseong Kim, Seungcheol Yang, Yeongil Jung |
On-Site Speaker (Planned) |
Janghyeok Pyeon |
Abstract Scope |
The glass-like thermal conductivity behavior has been observed in the fluorite-type Y<sub>3</sub>NbO<sub>7</sub>, which has a great potential as a high-temperature thermal barrier coating material. Therefore, in this study, the heavier Ta<sup>5+</sup> with same ionic radius was selected to substitute Nb<sup>5+</sup> in the Y<sub>3</sub>NbO<sub>7</sub> in order to distort the lattice structure, forming various compositions of Y<sub>3</sub>(Nb<sub>1-x</sub>Ta<sub>x</sub>)O<sub>7</sub> (x=0.1~0.5). The crystal structure was characterized by an X-ray diffraction and Raman spectroscopy. The highest coefficient of thermal expansion and lowest thermal conductivity at 1273K were 10.2-6/K at Y<sub>3</sub>(Nb<sub>0.9</sub>Ta<sub>0.1</sub>)O<sub>7</sub> and 1.2 W/mK at Y<sub>3</sub>(Nb<sub>0.5</sub>Ta<sub>0.5</sub>)O<sub>7</sub>, respectively, resulting from the long-range disordered atomic arrangement and highly distorted crystal structure. Mechanical properties of Y<sub>3</sub>(Nb<sub>1-x</sub>Ta<sub>x</sub>)O<sub>7</sub>, such as elastic modulus and hardness, decreased as increasing the addition amount of Ta<sup>5+</sup>. The thermo-physical properties of Y<sub>3</sub>NbO<sub>7</sub> can be optimized via the substitution of Ta<sup>5+</sup>, indicating that the Y<sub>3</sub>(Nb<sub>1-x</sub>Ta<sub>x</sub>)O<sub>7</sub> system has a potential for application as a new thermal insulating material. |