Influence of pulsed arc parameters on powder production in ethanol

Abstract

Powder consisting nickel and carbon particles were synthesized using a pulsed arc between Ni electrodes submerged in pure ethanol. The ethanol was arc treated for 5 min with 20 and 40 μs duration pulses, at a repetition rate of 100 Hz. The pulse energy was varied in a range of 7.7–192 mJ. Powder samples were obtained by extracting liquid from the treatment vessel after a pre-determined sedimentation time, or by allowing the liquid to evaporate from the vessel, and collecting the residue. The samples were examined by HRSEM, EDX and XRD. Dependencies of the particle structure and size distribution, and the powder production rate and composition, on the pulse energy and duration were studied. The powder samples consisted of nickel and carbon particles. The surface of the nickel particle had a carbon coating. The Ni concentration increased from 32% to 46%, and the C concentration decreased from 68% to 54%, when the pulse energy was increased from 7.7 to 100 mJ with 20 μs pulses. For 40 μs pulses the same changes of Ni and C concentrations were obtained when the pulse energy increased from 60 to 100 mJ. The production rate of the Ni and C particles linearly increased with pulse energy. The particle quantity and size distribution width increased with pulse energy. The maximum particle diameter increased from 70 to 550 nm while its minimum diameter remained ∼ 50 nm when the pulse energy increased from 7.7 to 48 mJ with pulse duration of 20 μs.