| 초록 |
Tri-isotropic(TRISO) coatings on zirconia surrogate beads were conducted by FB-CVD(Fluidized-bed vapor deposition) method. The silicon carbide layer is particularly important among coated layers because it acts as a miniature pressure vessel and a diffusion barrier to gaseous and metallic fission products in the TRISO coated particle. In this study, we have obtained nearly stoichiometric composition in the SiC layer coated at 1400℃, 1500℃ and 1400℃ with 20 vol.% Methytrichlorosilane(MTS), However, the composition of the SiC layer coated at 1300-1350℃ shows discrepancy from stoichiometric ratio(1:1). The density is remarkably decreased with decreasing SiC deposition temperature because of nano size pores, The property of high density of SiC layer (≥3.19 g/㎤) easily obtained at 1500℃ and 1400℃ with 20 vol.% MTS was not changed at 1900℃ annealing temperature simulating the reactor operational temperature. The mechanical property evaluation was limited owing to the inaccurate values of hardness and Young’s modulus measured by the nano-indentation method. |
