Low Infrared Emissivity Yb-Doped CeO₂ With Low Thermal Conductivity and High Thermal Expansion Coefficient

Developing low-infrared-emissivity materials with excellent high-temperature properties remains a significant challenge for infrared stealth of hot-end components in the 3−5 µm waveband. To meet this challenge, Yb was selected as the dopant, and a series of Ce_1−xYb_xO₂ (x = 0.1, 0.2, 0.3) solid solutions were prepared by the solid-state reaction sintering method. The effects of varying Yb doping contents on the emissivity of CeO₂ were systematically investigated. When the Yb dopant concentration is 20% (x = 0.2), Ce_0.8Yb_0.2O₂ shows the lowest infrared emissivity (0.21 at 400°C), attributed to its highest oxygen vacancy concentration and electrical conductivity. In addition, Ce_0.8Yb_0.2O₂ exhibits a thermal conductivity of 1.64 W·m⁻¹·K⁻¹ at 1473 K and a thermal expansion coefficient of 13.22 × 10⁻⁶ K⁻¹, matching that of nickel-based superalloys. These results demonstrate that Ce_0.8Yb_0.2O₂ has the potential to be applied as a low-infrared-emissivity coating material in high-temperature environments.