Production of Spherical Boron-Carbide Particles Encapsulated in a Graphite Shell

Abstract

Laser ablation makes it possible to obtain boron-carbide nanoparticles suitable for subsequent use in boron neutron capture therapy. However, particles of boron and boric acid are formed in parallel. Boric acid is harmful to the human body, and boron can naturally form boric acid. A method is proposed for reducing the toxicity of the synthesis of boron-carbide nanoparticles by laser ablation by adding free carbon to the reaction and replacing the traditionally used buffer medium, ethyl acetate. Purified water is used as a dispersing medium. It is shown that the described technology has prospects for reducing the level of toxicity due to the choice of a suitable buffer medium. The formation of boron carbide is recorded by transmission electron microscopy and XRD analysis. The formed particles are predominantly spherical in shape and have a carbon shell. A mechanism is proposed for the formation of such a shell due to the diffusion of carbon from the bulk of the particle through the domain boundaries.