Silicon carbide(SiC) layer is particularly important tri-isotropic (TRISO) coating layers because it acts as aminiature pressure vessel and a diffusion barrier to gaseous and metallic fission products in the TRISO coated particle.
The high temperature deposition of SiC layer normally performed at 1500-1650oC has a negative effect on the propertyof IPyC layer by increasing its anisotropy. To investigate the feasibility of lower temperature SiC deposition, the influenceof deposition temperature on the property of SiC layer are examined in this study. While the SiC layer coated at1500oC obtains nearly stoichiometric composition, the composition of the SiC layer coated at 1300-1400oC shows discrepancyfrom stoichiometric ratio(1:1). 3-7 μm grain size of SiC layer coated at 1500oC is decreased to sub-micrometer(<1 μm) -2 μm grain size when coated at 1400oC, and further decreased to nano grain size when coated at 1300-1350oC. Moreover, the high density of SiC layer (≥3.19 g/cm3) which is easily obtained at 1500oC coating is difficult toachieve at lower temperature owing to nano size pores. the density is remarkably decreased with decreasing SiC depositiontemperature.