Microstructure and Thermomechanical Properties of Atmospheric Plasma-Sprayed Yb 2 O 3 Coating
In this study, a Yb2O3 coating was fabricated by the atmospheric plasma spray technique. The phase composition, microstructure, and thermal stability of the coating were examined. The thermal conductivity and thermal expansion behavior were also investigated. Some of the mechanical properties (elastic modulus, hardness, fracture toughness, and flexural strength) were characterized. The results reveal that the Yb2O3 coating is predominantly composed of the cubic Yb2O3 phase, and it has a dense lamellar microstructure containing defects. No mass change and exothermic phenomena are observed in the thermogravimetry and differential thermal analysis curves. The high-temperature x-ray diffraction results indicate that no phase transformation occurs from room temperature to 1500 °C, revealing the good phase stability of the Yb2O3 coating. The coefficient of thermal expansion of the Yb2O3 coating is (7.50-8.67) × 10−6 K−1 in the range of 200-1400 °C. The thermal conductivity is about 1.5 W m−1 K−1 at 1200 °C. The Yb2O3 coating has excellent mechanical properties and good damage tolerant. The unique combination of these properties implies that the Yb2O3 coating might be a promising candidate for T/EBCs applications.
Publisher URL: https://link.springer.com/article/10.1007/s11666-018-0733-z