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- Title
A Promising Radiation Thermal Protection Coating Based on Lamellar Porous Ca‐Cr co‐Doped Y<sub>3</sub>NbO<sub>7</sub> Ceramic.
- Authors
Chen, Guoliang; Fu, Haoyang; Zou, Yongchun; Wang, Shuqi; Gao, Yongwang; Yue, Tongtong; Cao, Jianyun; Wang, Yaming; Qiu, Jun; Zhao, Junming; Ouyang, Jiahu; Jia, Dechang; Shuai, Yong; Zhou, Yu
- Abstract
Dissipation of heat efficiently from a hot object via radiation while minimizing the inward heat conduction is the key requirement of radiation thermal protection. In this study, a Ca‐Cr co‐doped Y3NbO7 coating with lamellar porous structure is fabricated, which shows an ultra‐low thermal conductivity (<0.7 W m−1 K−1) and near‐unity emissivity (>0.9) across a broad wavelength range of ≈1–24 µm. This record high emissivity to thermal conductivity ratio (≈1.3) is experimentally and theoretically revealed from a multi‐scale perspective. The diffusoin‐mediated thermal conduction feature of niobates combined with lamellar porous structure of the coating reduces its thermal conductivity to an impressive 0.5 W m−1 K−1 at 25 °C, surpassing the theoretical amorphous limitation of 0.72 W m−1 K−1. Experiments and FDTD calculation results demonstrate that the intrinsic emissivity dips at shallow extinction wavelengths (1 and 8 µm) and strong phonon‐polariton resonances wavelengths (>13 µm) can be effectively compensated by the multiple scattering/absorption and gradual modulation of conical shape/effective refractive index induced by surface micro‐protrusion structures, respectively. Furthermore, the coating exhibits robust mechanical and thermal stability with a high bonding strength (18.3 MPa) and thermal expansion coefficient (≈11 × 10−6 K−1 at 1200 °C) comparable to YSZ, showing great potential in the radiation thermal protection field.
- Subjects
RADIATION protection; HEAT radiation &; absorption; DOPING agents (Chemistry); MULTIPLE scattering (Physics); SURFACE coatings; CHROMIUM isotopes; THERMAL conductivity
- Publication
Advanced Functional Materials, 2023, Vol 33, Issue 47, p1
- ISSN
1616-301X
- Publication type
Article
- DOI
10.1002/adfm.202305650