A novel multilayer high temperature solar absorber coating based on high-entropy alloy NbMoTaW: Optical properties, thermal stability and corrosion properties

With the development of new materials and technology, high entropy alloy (HEA) nitride films have attracted much attention of researchers due to their excellent optical properties and mechanical properties. Herein, a novel SS/NbMoTaWN (HEAN)/NbMoTaWON (HEAON)/SiO2 coatings are prepared, which shows a high spectral selectivity of alpha/epsilon = 0.944/0.12. The preparation and optimization of the coating are studied by combining experiments with ellipsometric program and CODE software. High temperature thermal stability test is performed in depth, which proves that the coating could bear 400 degrees C in air for 2 h, and 600 degrees C for 2 h in vacuum. Long-term thermal stability researches indicate that the SSACs still keep good optical properties (alpha = 0.902, epsilon = 0.106) even after annealing at 600 degrees C for 100 h. The failure mechanism is analyzed by XRD and Raman spectra. In addition, neutral salt spray test is performed to investigate the anti-corrosion ability, which indicates the coating has a good optical performance after soaking in 3.5 wt% NaCl solution for 30 days. Obviously, this work provides a new strategy to construct solar absorber coatings based on NbMoTaW high entropy alloy. (C) 2021 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Automated summary

A novel high entropy alloy nitride film coating with high spectral selectivity and excellent thermal stability was prepared and studied. The coating showed good optical properties even after long-term thermal stability testing and demonstrated good corrosion resistance in a neutral salt spray test. This work provides a new strategy for constructing solar absorber coatings based on NbMoTaW high entropy alloy.