Thermostability and weatherability of TiN/TiC-Ni/Mo solar absorption coating by spray method-laser cladding hybrid deposition

A novel one-layer micrometre-sized TiC/TiN-based spectrally selective coating was designed and fabricated via spray method-laser cladding hybrid deposition in air. The laser cladding was used to obtain TiC/TiN-Ni/Mo cermet coatings with desirable optical properties. In particular, an absorptance (α) of ~84% and thermal emissivity (ε) of ~5% at 300 K were calculated at a TiC/TiN weight ratio of 1:1. In addition, the thermal stability of the coating was outstanding after heat treatment at 650 °C for 200 h. The absorptance and emissivity of the 30 wt.% TiC-30 wt. %TiN-20 wt.% Ni-20 wt.% Mo cermet coatings were respectively 82% and 4%, respectively, at 650 °C. Furthermore, the cermet coating also exhibited excellent weatherability, indicateing that TiC/TiN-based cermets are suitable for spectrally selective materials. Moreover, the laser cladding was demonstrated as an improved and novel preparation technology for manufacture of solar selective absorbing coatings.