W@Boron Nitride Core-Shell Nanoparticles for Radiation Shielding

Abstract

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 gamma ray shielding with an attenuation coefficient of 0.357 cm(-1). These core-shell particles can effectively shield the secondary gamma rays emitted during the thermal neutron capture process of B-10 as well as the primary gamma 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.