Synthesis and thermal shock evaluation of porous SiC ceramic foams for solar thermal applications

Reticulated porous ceramics with structural features spanning across multiple length scales are emerging as the primary media in a variety of demanding mass and heat transfer applications, most notably solar-assisted synthetic fuel processing. In this study, we focus on engineering of the open pore silicon carbide (SiC)-based foams in such catalytic applications. We evaluate the mechanical integrity and thermal stability of these porous structures. X-ray tomography analyses of the 3D structures reveal the presence of dual pore size distribution different by up to an order of magnitude in length scale. We further study the effect of thermal shock—induced via water quenching—on the SiC structures and we conclude that the mechanical properties of the ceramic foams are significantly reduced after thermal stress. Comparison of SEM micrographs—before and after thermal shock—reveals that needle-like features appear inside the foam matrix. These elongated defects may be responsible for structural and mechanical weakening.