Thermal stability and Weatherability of Single-Layer Micron Scale Cermets Solar Selective Absorbing Coatings by Laser Cladding

Abstract

The thermal stability of solar absorber coatings at high temperature is the most important challenge for solar energy photo-thermal utilization. A new one layer micrometer-size TiC/TiN-based cermet coating was designed and fabricated with laser cladding method in air. The result indicated the laser cladding could be used to obtain a TiC/TiN-Ni/Mo cermet coating with the desired optical properties. An absorptance (α) of ∼84% and a thermal emissivity (ɛ) of ∼5% at 300 K were calculated. Furthermore, the thermal stability of the coating was outstanding after heat-treatment. The absorptance and emissivity of the TiC/TiN-based cermet coating were respectively 82% and 4.1% at 650°C. The results indicated that TiC/TiN-Ni/Mo cermets are suitable for spectrally selective materials. Furthermore, the cermet coating also possesses excellent weatherability based on the test of the corrosion resistance. The results indicated that TiC/TiN-Ni/Mo cermets are suitable for spectrally selective materials. Moreover, the laser cladding was found to be an improved and novel preparation technology in the field of solar selective absorbing coatings.