In Situ TEM Study of Radiation Resistance of Metallic Glass–Metal Core–Shell Nanocubes

Abstract

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, in situ 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 Au4+ ions. The formation of internal defects in bare Au nanocubes was observed at a fluence of 7.5 × 1011 ions/cm2 (0.008 dpa), and morphological changes such as surface roughening, rounding of corners, and formation of nanofilaments began at 4 × 1012 ions/cm2 (0.04 dpa). In contrast, the Ni–B MG-coated Au nanocubes (Au@NiB) showed minimal morphological changes at a fluence of 1.9 × 1013 ions/cm2 (0.2 dpa). The MG coating maintains its amorphous nature under all irradiation conditions investigated.

Thermal Stability and Radiation Tolerance of Lanthanide-Doped Cerium Oxide Nanocubes

“…The poor irradiation stability observed in this work is similar to that seen in crystalline tungstate nanoparticles irradiated with heavy ions [23,24]. This in stark contrast to other amorphous ceramic nanoparticles and core@shell nanoparticles that have been explored, which suggests that the amorphous phase may be extremely important for radiation stability [25,26]. As such, future work will explore the role of both phase and doping on the stability of ceramic nanoparticles for both free-standing nanoparticles, as shown in this study, as well as those embedded in composite matrixes.…”

Synthesis of multifunctional amorphous metallic shell on crystalline metallic nanoparticles

“…We have previously shown that Au nanocubes can also be coated in a similar manner. 26 The presence of boron in the NiB structure has been observed by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray photoelectron spectroscopy (XPS) in our previous study 20 and by others. 23,[33][34][35][36][37][38][39][40][41] The current synthesis strategy for NiB shell synthesis is similar to these previous studies indicating the presence of boron in the shell.…”

“… 24 Due to their magnetic properties, TMBs can be simultaneously used as contrast agents in magnetic resonance imaging (MRI) and as a cancer treatment via magnetic hyperthermia. 24 Amorphous NiB-coated Au nanocubes were shown to provide superior radiation tolerance when compared to silica, which makes them promising coatings for nanoparticle-enhanced radiation therapy 26 and as delivery vehicles for the non-radioactive isotope 10 B for neutron capture therapy. 25 The combination of these properties with a plasmonic core could enable multimodal imaging such as surface enhanced Raman and MRI.…”