High-temperature optical properties and stability of AlxOy–AlNx–Al solar selective absorbing surface prepared by DC magnetron reactive sputtering

AlxOy–AlNx–Al selective absorbing surface was prepared by DC magnetron reactive sputtering with aluminum alloy (LY13)11Al alloy (LY13): Al 90.3%∼93.3%; Cu 4%∼7%; Fe 0.6%; Zn 0.6%; Si 0.7%; Mg 0.5%; Ti 0.15%; others 0.15%. r and argon. The studies were carried out to access the high-temperature (400°C–600°C) optical properties and stability of the coatings. The coatings were found to withstand heating at 600°C for 30 min in 4.5×10−3 Pa vacuum with absorptance 0.94 and emittance 0.07 after annealing. After heating at 450°C for 10 h, the specimen still had good performance whose absorptance and emittance was 0.93 and 0.07, respectively. Auger electron spectroscopy was used to analyse the structure of the solar selective surface before and after annealing.