Ion irradiation effect on spark plasma sintered silicon carbide ceramics with nanostructured ferritic alloy aid

Abstract

Silicon carbide (SiC) is a promising material with excellent chemical and physical performance under irradiation for advanced nuclear applications. The addition of nanostructured ferritic alloy (NFA) has been proven beneficial for the densification of SiC ceramics based on our previous work. To understand their microstructural evolution and irradiation resistance, spark plasma sintered (SPSed) SiC ceramics with and without NFA aid (0 vol% NFA-100 vol% SiC, 2.5 vol% NFA-97.5 vol% SiC, and 5 vol% NFA-95 vol% SiC) were exposed to 5 MeV Si ++ irradiation. The ion irradiation strongly modifies the surface morphology with isolated sand dune shaped structures, which can be explained by the Bradley-Harper (B-H) theory. SRIM simulation for both the pure SiC and NFA-SiC predicts similar surface damage of~45 dpa and peak damage of~790 dpa at~2.0 lm depth. For the actual samples, the SiC matrix is completely amorphous up to~2.2 lm thickness (from the surface dune valley to the amorphous layer boundary), which is consistent with the SRIM predicted depth of~2.3 lm. Reaction product (Fe, Cr) 3 Si in the NFA-SiC samples maintains a crystalline structure with dislocation loops. A defect rate model is applied to understand the fundamental difference in ion irradiation resistance between SiC and (Fe,Cr) 3 Si. K E Y W O R D S defects, microstructure, nanostructured ferritic alloy aid, Si ++ ion irradiation, silicon carbideHow to cite this article: Ning K, Lu K. Ion irradiation effect on spark plasma sintered silicon carbide ceramics with nanostructured ferritic alloy aid.

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