W@Boron Nitride Core–Shell Nanoparticles for Radiation Shielding

Tungsten@boron nitride (W@BN) core–shell nanoparticles have been synthesized using an in situ arc discharge method by conjointly leading tungsten atoms and borazine precursors to the arc core. Metal atoms and BN radicals self-assemble to form core–shell nanoparticles, where hexagonal boron nitride (h-BN) wraps around the surface of the core tungsten nanoparticles, originating from their metallic and covalent bonding nature. The core–shell structure was analyzed by various methods, such as HR-TEM, EDS, XRD, and XPS. The coating of h-BN on the W nanoparticles improved the oxidation resistance of the W nanoparticles, as evidenced by the oxidation temperature shift in thermogravimetric analysis. The fabricated 20 wt % W@BN/BP epoxy composite exhibited thermal neutron shielding with an absorption coefficient of 0.351 mm –1 as well as γ ray shielding with an attenuation coefficient of 0.357 cm –1 . These core–shell particles can effectively shield the secondary γ rays emitted during the thermal neutron capture process of 10 B as well as the primary γ rays. This study will lead to the utilization of W@BN core–shell nanoparticles in space or extreme environments, where radiation shielding is critical for human activity.