To develop more reliable bulk solar absorber materials, the ZrB 2 –SiC ceramic composites were synthesized via an economical method of pressureless sintering. The phase composition, microstructure, flexural strength and solar absorptance of the as-synthesized ZrB 2 –SiC ceramic composites were systematically investigated at both room temperature and elevated temperatures. The results showed that ZrB 2 –SiC ceramic composites exhibited good room-temperature performance with a flexural strength of 17.86 MPa and a solar absorptance of 85.7%. After oxidation at 1000 °C and 1100 °C for 100 h, a dense oxide layer characterized with ZrSiO 4 particles embedding within a borosilicate glass phase was formed on surface of the sample, which reinforced the skeleton structure of the sample and significantly enhanced the flexural strength with increases of 46.0% and 99.6%, respectively. The solar absorptance of the sample after oxidation at 1000 °C and 1100 °C was decreased by 2.26% and 27.81%, respectively. The sharp decline of the solar absorptance after oxidation at 1100 °C was primarily attributed to the variation of the composition. The results demonstrated the excellent performance durability of the ZrB 2 –SiC ceramic composites in air below 1000 °C, highlighting their potential as high-temperature solar absorber materials.
Cao et al. (Sat,) studied this question.