Fabrication, microstructures and optical reflectivity of TiAlN/NiCr composite coating

Abstract

In this work, TiAlN/NiCr composite coatings were prepared by reactive magnetron sputtering technique. Firstly, a single absorber layer was prepared, and at the substrate temperature of 300 °C, a “prismatic” structure is formed on the surface of the TiAlN film, which has good light absorption properties under these conditions. In order to further improve its absorption, the TiAlN/NiCr bilayer coating was designed, and the effects of etching in two different solutions and subsequent annealing treatments on the surface microstructure and reflectivity of the bilayer coating were investigated. These results show that TiAlN/NiCr bilayer coatings fabricated in various etching solutions can further improve light absorption performance, with the TiAlN/NiCr-CAN coating showing particularly good thermal stability and exhibiting further improvements in absorption performance after 500 °C/2 h of annealing. Low-temperature applications are the only ones for which the TiAlN/NiCr–HF coating is suitable, since it fails at the annealing condition of 300 °C/2 h.