TEM Study of Radiation Resistance of Metallic Glass-Metal Core-Shell Nanocubes.

Radiation damage can cause significantly more surface damage in metallic nanostructures than bulk materials. Structural changes from displacement damage compromise the performance of nanostructures in radiation environments such as nuclear reactors and outer space, or used in radiation therapy for biomedical treatments. As such, it is important to develop strategies to prevent this from occurring if nanostructures are to be incorporated into these applications. Here, transmission electron microscope ion irradiation was used to investigate whether a metallic glass (MG) coating mitigates sputtering and morphological changes in metallic nanostructures. Dislocation-free Au nanocubes and Au nanocubes coated with a Ni-B MG were bombarded with 2.8 MeV Au ions. The formation of internal defects in bare Au nanocubes was observed at a fluence of 7.5 × 10 ions/cm (0.008 dpa), and morphological changes such as surface roughening, rounding of corners, and formation of nanofilaments began at 4 × 10 ions/cm (0.04 dpa). In contrast, the Ni-B MG-coated Au nanocubes (Au@NiB) showed minimal morphological changes at a fluence of 1.9 × 10 ions/cm (0.2 dpa). The MG coating maintains its amorphous nature under all irradiation conditions investigated.