Boron carbide synthesis in low-voltage DC electric arc initiated in open air

We describe a method of obtaining ultrafine boron carbide (B$_{13}$C$_{2}$) powder using the effect of a dc electric arc on a mixture of initial reactants containing carbon and boron. A peculiarity of the proposed method is that it can be implemented using arc discharge operating in open air without any vacuum equipment and protective inert gas atmosphere. X-ray diffraction data showed that the synthesized product in the general case contained three crystalline phases: boron carbide (B$_{13}$C$_{2}$), graphite (C), and boron oxide (B$_2$O$_3$). Electron-microscopic examination showed that the average size of boron carbide particles ranged from $\sim$50 nm to $\sim$2 $\mu$m.