Advanced ceramics (made up of oxides, nitrides, carbides and non-silicate glass) present interesting properties, among others, thermal insulation, lightness, high specific surface area, thermal shock resistance, mechanical strength and chemical inertness. Consequently, the development of ceramics for high temperature applications has become an emerging area of research. These ceramics must exhibit certain properties including resistance to creep deformation at interfaces, chemical stability, oxidation resistance, low volatility, thermal shock resistance and toughness at high temperatures.

Solar-driven thermochemical processes and other high temperature solar applications require a high concentration of solar radiation, often exceeding 100 W/cm2. For this purpose, advanced ceramics are a good choice, since these materials are capable to withstand temperatures up to 1400 ?C or higher, while remaining stable against damaging morphological changes. Moreover, for this use, selected materials should be capable of supporting high flux densities and temperatures for thousands of cycles, as these systems operate daily with start-up and shut-down procedures.
In the present work, several ceramic materials (alumina, zirconia, alumina-zirconia mixtures, mullite, etc.) have been studied to be used in solar reactors. Samples have been prepared by uniaxial pressing and sintered in air, determining their properties at different temperatures and, later, ongoing ageing mechanisms to analyse the changes in their mechanical, thermal and optical properties.

The work has been carried out thanks to the project "Boost to the solar thermal H2 production via the development and validation of new materials for ceramic solar receivers with improved durability (HIDROFERR)”, with project reference PID2020-118599RB-I00, funded by Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación, with Digital Object Identifier 10.13039/501100011033, and FEDER Funds.
 
References
1.            T. A. Otitoju, P. U. Okoye, G. Chen, Y. Li, M. O. Okoye, S. Li. Advanced ceramic components: Materials, fabrication, and applications. Journal of Industrial and Engineering Chemistry 85 (2020) 34–65. https://doi.org/10.1016/j.jiec.2020.02.002
2.            A. Vidal, D. Martinez. An ageing protocol for testing high temperature solar materials for thermochemical applications. Solar Energy Materials & Solar Cells 212 (2020) 110572. https://doi.org/10.1016/j.solmat.2020.110572