Synthesis of Chromium Diboride in an Arc-Discharge Atmospheric Plasma

The authors have described a method for synthesis of the crystalline phases of chromium boride CrB and CrB₂ at atmospheric pressure without introducing additional modifiers improving the reactivity of the original charge. The formation of chromium borides was implemented under the action of an arc discharge with the original vacuum free dc electric-arc reactor. The influence of the parameters of the reactor on the phase composition of the obtained samples has been investigated. It has been established that the impact of an arch discharge of strength 200 A and duration 60 s on a mixture of Cr and B powders in a 1.0:2.55 atomic ratio ensures the formation of chromium diboride CrB₂. The properties of the obtained powders have been studied by the methods of x-ray diffraction, scanning electron microscopy, and transmission electron microscopy.