Thermal stress durability and optical characteristics of a promising solar air receiver based black alumina ceramics

In solar thermal technology, solar receiver materials with high solar absorptivity and photocatalytic efficiency have recently become a mandatory requirement for promoting and maximizing the released thermal and electrical energy. This paper presents a detailed study of the optical performance and thermal stress durability of the promising solar receiver material, black Al2O3/CuO ceramics. Different Al2O3/CuO ceramics with different CuO content (10–40 wt%) were obtained by the pressureless sintering method. Optical properties such as solar absorbance and reflectance, band gap energy and photoluminescence are inclusively investigated. The thermal stress resistance of the obtained ceramic receivers is simulated using the finite element modeling (FEM) method at different temperatures. Results indicated that adding and increasing the content of CuO to Al2O3 has a significant role in transforming alumina from a non-solar light-absorbed material to a solar absorber material with high absorptivity in the Ultraviolet–Visible-Near Infrared (UV-VIS-NIR) spectrum. Composite with 40 wt% CuO has recorded the maximum absorbance of 75% in the visible light region. Moreover, Al2O3/CuO ceramics gave multiple graded band-gaps in the range of (1.6–5 eV). Composites with high wt% of CuO have the most increased photocatalytic activity and light emissivity efficiency. Thermal stress analysis of the different ceramics showed outstanding stress durability with uniform heat distribution. Hence, black Al2O3/CuO ceramics can be considered ideal solar absorber materials with high sustainability and durability at high temperatures.