PNNL

Abstract

This study examines C+ and He+ ion irradiation induced amorphization processes in 3C-SiC nanograins embedded in an amorphous SiC matrix. Raman spectroscopy and Rutherford backscattering spectrometry are used for damage characterization. SiC grains with an average size of either ~6 or ~20 nm were observed to be fully amorphized to a lower dose at room temperature compared to their monocrystalline counterpart under the identical irradiation condition. In addition to damage accumulation induced amorphization in the grains, preferential amorphization at the crystalline/amorphous interfaces could play a significant role. This interface-driven amorphization proceeds at comparable rates for C+ and He+ ion irradiations. The results may have an important implication for nanocrystalline SiC to be applied in advanced nuclear reactors.