| Abstract Scope |
Polymer-derived silicon carbide has strong potential for nuclear and high-temperature applications because SiC provides excellent thermal stability, oxidation resistance, mechanical stability, and fission-product retention capability. In TRISO fuel particles, the SiC layer protects the fuel kernel and retains metallic and gaseous fission products under reactor operating conditions. In this study, surrogate TRISO fuel particles were coated using an SMP-10 polycarbosilane-based precursor and added with ball-milled nano-SiC filler to reduce shrinkage during pyrolysis. The coated particles were pyrolyzed in argon atmosphere at 1000, 1300, and 1600 °C to study densification, phase evolution, and microstructure changes. Uniform SiC-based coatings with an average thickness of 82 ± 5 μm were obtained. With increasing pyrolysis temperature, the amorphous polymer derived SiC network progressively transformed into a more ordered and crystalline SiC structure. The 1600 °C coating showed nano SiC crystallization, better densification and nano hardness of 18 ± 1 GPa compared with lower-temperature coatings. |