Near-Infrared Trapping by Surface Plasmons in Randomized Platinum-Ceramic Metamaterial for Thermal Barrier Coatings

As the operation temperature of next generation gas turbine is targeted to be 1800 °C toward a higher efficiency and lower carbon emission, the near-infrared (NIR) thermal radiation becomes a major concern for the durability of the metallic turbine blades. Although thermal barrier coatings (TBCs) are applied to provide thermal insulations, they are translucent to the NIR radiation. It is a major challenge for TBCs to achieve optically thick with limited physical thickness (usually < 1 mm) for effectively shielding the NIR radiation damage. Here, an NIR metamaterial is reported, where a Gd₂ Zr₂ O₇ ceramic matrix is randomly dispersed with microscale Pt (0.53 vol%) nanoparticles with a size of 100-500 nm. Attenuated by the Gd₂ Zr₂ O₇ matrix, a broadband NIR extinction is achieved through the red-shifted plasmon resonance frequencies and higher-order multipole resonances of the Pt nanoparticles. A very high absorption coefficient of ≈3 × 10⁴ m^-1 , approaching the Rosseland diffusion limit for a typical coating thickness, minimizes the radiative thermal conductivity to ≈10^-2  W m^-1 K^-1 and successfully shields the radiative heat transfer. This work suggests that constructing a conductor/ceramic metamaterial with tunable plasmonics could be a strategy to shield NIR thermal radiation for high temperature applications.