Dark alumina for novel solar receivers

Concentrating solar power is one of the most promising solar energy exploitation technologies. Its efficiency improvement needs a significant increase of operating temperatures, from the current 500 degrees C to 900 degrees C. Alumina (Al2O3) ceramics are refractory materials characterized by a huge industrial interest, mature production techniques and low cost. In the present work, we successfully synthesized dark ceramic Al2O3 bulks, to evaluate their potential as high-temperature solar absorbers for CSP. We investigated process-dependent ceramics composition, microstructure and optical properties, obtaining pellets with a solar absorbance even higher than that of SiC. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.