Multi-mechanism synergy study of Ce doped ZnO ceramics towards low infrared emissivity property at high temperatures

High temperature material with low infrared emissivity in 3–5 μm waveband plays a crucial role in the infrared stealth capability of hot-end aircraft components. In this study, 3 mol% Ce doped ZnO ceramic powders were annealed at various temperatures to reduce their infrared emissivity. The effects of the annealing temperature on the lattice structure, microscopic morphology, and elemental valence variation in the ZnO ceramic powders were systematically investigated. Additionally, a conductivity–dielectric–lattice vibration synergy theory was proposed to provide insights about the changes in the infrared emissivity of the ZnO ceramic powders. The infrared emissivity of the sample powder gradually decreased to its lowest value (0.092 at 500 °C) as the annealing temperature increased to 1100 °C, exhibiting a U-shaped curve from room temperature to 800 °C. Furthermore, the obtained powder was used as a filler to prepare a low infrared emissivity coating, which exhibited an infrared emissivity of 0.213 in 3–5 μm waveband at 500 °C. An infrared thermographic analysis of the coating indicated that it significantly suppressed infrared radiation at 500 °C, demonstrating an excellent high temperature infrared stealth performance.