Thermal stability and optical properties of single-layer nano-composite TiN/TiC-Ni/Mo solar-selective-absorbing coatings by laser cladding

Abstract

Currently, the most important challenge for solar energy photo-thermal utilization is the thermal stability of solar absorber coatings at high temperature. The new one-layer nano-composite TiN/TiC-based cermet coatings were designed and fabricated with laser-cladding method in the air. The result indicated the laser cladding could be used to obtain 30\xa0wt.%, TiN-30\xa0wt.%, TiC-20\xa0wt.%, and Ni-20\xa0wt.% Mo cermet coatings with the desired optical properties. In particular, an absorptance (α) of\u2009~\u200980.1% and a thermal emissivity (e) of\u2009~\u20092% at 300\xa0K were calculated when the weight rate of nano-particles/micro-particles is 1:1. In addition, the thermal stability of the coating was outstanding after heat treatment at 650\xa0°C for 6\xa0h. The absorptance and emissivity of cermet coating were, respectively, 80.8% and 1.9% at 650\xa0°C. The results indicated that nano-composite TiN/TiC-Ni/Mo cermets are suitable for spectrally selective materials. Moreover, the laser cladding was found to be an improved and novel preparation method in the field of solar-selective-absorbing coatings.