Modernization of non-vacuum electric arc reactor for boron carbide powder synthesis

Abstract

The paper describes non-vacuum method of boron carbide powder production using a modernized electric arc reactor. According to the results of X-ray phase analysis, the boron carbide B4C phase dominates in the synthesis product, which is ensured by the use of a special carbon screen separating the initiation and combustion zone of the arc discharge from the synthesis zone. Using the modernized scheme of the discharge circuit of the arc reactor, it was possible to reduce the ratio of the intensity of the main maximum of the graphite phase to the main maximum of the boron carbide phase by 12 times: previously IC/IB4C = 3.617, in this work IC/IB4C = 0.285. In addition, the energy characteristics of the synthesis process were investigated, the amount of supplied energy (~372 kJ during the synthesis time ~60 s), the average discharge power (~6 kW) were determined; the mass balance of the system was compiled. Using a tungsten-rhenium thermocouple, the temperature in the fusion zone with and without the use of thermal insulation of the discharge circuit was measured. It was determined that the use of gas-concrete block “Sibit” as thermal insulation allowed reducing mass losses of the large graphite crucible by 2 times and increasing the temperature in the cavity of the internal graphite crucible from 1508 °C to 1642 °C, when using the graphite crucible without the initial mixture.