Helium ion irradiation effects on microstructure evolution and mechanical properties of silicon oxycarbide

In this study, silicon oxycarbide (SiOC) was fabricated by pyrolysis of a polysiloxane precursor at 1000 degrees C and 1500 degrees C in an Ar atmosphere and evaluated as a new nuclear fuel coating material. The 1000 degrees C pyrolyzed SiOC is fully amorphous while the 1500 degrees C sample contains crystalline beta-SiC nanodomains, a turbostratic carbon network, and an amorphous SiOC matrix. After 100 keV He ion irradiation, no detectable microstructural changes are observed for the 1000 degrees C pyrolyzed SiOC. However, the 1500 degrees C pyrolyzed SiOC shows amorphization of crystalline phases. Neither sample has He bubbles, elemental segregation, or voids after irradiation. Irradiation induced hardening is observed for all the samples. Both hardness and elastic modulus values increase with irradiation. These high temperature stable and amorphous phase dominant SiOC materials are promising for the of irradiation-tolerant fuels for advanced nuclear reactors.

Automated summary

In this study, silicon oxycarbide (SiOC) was prepared by pyrolysis of a polysiloxane precursor at different temperatures and evaluated as a new nuclear fuel coating material. The findings show that the sample pyrolyzed at 1500 degrees C exhibits amorphization of crystalline phases after He ion irradiation, suggesting potential applications as irradiation-tolerant fuels for advanced nuclear reactors.