Suitability of layered Ti3SiC2 and Zr3[Al(si)]4C6 ceramics as high temperature solar absorbers for solar energy applications

• Spectrally selective absorbing properties of Ti3SiC2 and Zr3[Al(Si)]4C6 are investigated.
• The spectral selectivity of Ti3SiC2 and Zr3[Al(Si)]4C6 are 3.7 and 2.8, respectively.
• Ti3SiC2 and Zr3[Al(Si)]4C6 exhibit a low emissivity in the investigated temperature range.
• Suitability of Ti3SiC2 and Zr3[Al(Si)]4C6 as high-temperature solar absorbers is discussed.

Layered Ti3SiC2 and Zr3[Al(Si)]4C6 ceramics were prepared by hot-pressed sintering. The spectrally selective absorption properties of these layered carbides have been investigated and compared with those of TiC and ZrC. It is found that the Ti3SiC2 ceramic exhibits a solar absorbance of 0.70 and a thermal emissivity of 0.19, yielding spectral selectivity (absorbance divide by emissivity) of 3.7, while the spectral selectivity of Zr3[Al(Si)]4C6 is 2.8 (0.71/0.25). To evaluate the suitability of these ceramics as high-temperature absorbers for solar radiation, the investigation on the thermal stability and temperature dependent emittance was performed in air. Compared with TiC and ZrC, both Ti3SiC2 and Zr3[Al(Si)]4C6 show better thermal stability. Meanwhile, Ti3SiC2 and Zr3[Al(Si)]4C6 exhibit a low emissivity in the investigated temperature range, benefiting from their metal-like electrical conductivity.