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

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.