Thermal Plasma Synthesis of Metal-Boride Nanoparticles as a Functional Material for Gamma-Ray Shielding

Abstract

We performed a synthesis of metal-boride nanoparticles, which can shield both gamma rays and neutrons, and investigated the radiation shielding performance of the material. Titanium and nickel boride nanoparticles were synthesized in a triple thermal plasma jet system using titanium (Ti), nickel (Ni), and amorphous boron (a-B). The average sizes of the titanium boride and nickel boride were 46.3 and 31.4 nm, respectively. In the titanium boride, the TiB 2 phase was the major crystal structure with TiB as a minor phase, and the peak of the starting materials could not be observed. On the other hand, the nickel boride indicated a major crystal structure of NiB with an Ni peak observed from X-ray diffraction graphs. The synthesized powders were applied as a coating material to shield the radiation. The shielding performance of the coating material made with synthesized powder was analyzed using 137 Cs source (662 keV). The attenuation coefficient of the nickel boride and titanium boride was 0.246 and 0.197 cm −1 , respectively. Boron-rich boride is stable when confronting neutron and other types of radiation. Therefore, synthesized metal-boride nanoparticles can be used as substitutes for heavy metals, which become radioactive on account of neutron exposure.