Preparation and characterization of SiC layer of coated fuel particles for high-temperature gas-cooled reactor

Silicon carbide layer was prepared on coated fuel particles using chemical vapor deposition method. The function, preparation apparatus, proceeding condition and structure of SiC layer were systematically described. It was revealed that the deposited SiC layer has smooth and compact surface, no obvious holes, clear interfaces with inner/outer dense pyrocarbon layer. Composition and crystal structure analysis suggest that the main elements of SiC layer are Si and C and the Si/C molar ratio is close to 1:1. Stoichiometric β-SiC was obtained. Valence bond analysis indicates that Si-C covalent bonding is the major bonding in SiC layer.