Generation of micron and submicron particles in atmospheric pressure discharge in argon flow with magnesium, zinc, and boron carbide electrodes

We have investigated an atmospheric pressure discharge in the argon flow using magnesium, zinc, and boron carbide electrodes and determined the conditions for emission of the aerosol consisting of cathode material nanoparticles suspended in the gas mixture of argon and air. It has been experimentally demonstrated that for the discharge operating in the pulsed mode at a frequency up to 100 kHz and mean power up to 80 W, below the current level required for the transition to atmospheric pressure arc with cathode spots (from several milliamperes to 0.5 A), there exists an operating regime under which the cathode material takes part in the discharge maintenance and formation of the plasma flow. The coatings, produced as a result of aerosol condensation, have been studied using scanning and transmission electron microscopy. Elemental composition of the coatings has been studied using an energy-dispersion spectrometer. With the help of the employed techniques, we have determined that the coatings consist of nanoparticles, of the sizes varying from several to tens of nanometers, agglomerated in larger particles that include, in approximately equal parts, atoms of the cathode material and oxygen. The obtained result opens up new possibilities in generation of combined gas-metal flows under atmospheric pressure for the purpose of producing ultra-disperse powders. •Non-arc discharge can operate in a middle-frequency mode at atmospheric pressure.•As result of cathode thermal erosion the atomic particles are emitted from discharge.•The mixture of obtained particles and jet of working gas produce aerosol flows.•As result of condensation of aerosol the nanopowders can be obtained.