Design of polymer-derived SiC for nuclear applications from the perspective of heterogeneous interfaces

Polymer-derived SiC ceramics have been increasingly used in the field of nuclear energy. Herein, we synthetized polymer-derived SiCs with varying SiC/C heterogeneous interfacial properties by pyrolyzing the ceramics at different temperatures. Subsequently, we studied the effect of these interfacial properties on the irradiation behavior (i.e., volume swelling, amorphization, and mechanical properties) of the SiC ceramics. In the case of crystalline ceramics (pyrolyzed at 1150-1500 °C), the presence of a nano-crystalline graphite (NC-G) phase with sp3/sp2 hybridization ratios of 0.40-1.27 further enhanced the swelling resistance of nano-SiC by increasing the defect trapping capability of the interfaces. In contrast, amorphous ceramics (pyrolyzed at 900-1100 °C) showed low penetration depths and superior stabilities upon irradiation. These strong ion cascade blocking characteristics may result from the atomic short-range order of these materials. This approach allows optimum design of polymer-derived SiC with superior swelling resistance and stability under room-temperature irradiation.