Ni–C powder synthesis by a submerged pulsed arc in breakdown mode

Abstract

Abstract Powders of Ni–C nanoparticles were synthesized using a pulsed arc between Ni electrodes submerged in pure ethanol. The arc was ignited by inter-electrode breakdown. The ethanol was arc treated for 5 min with 1 μs duration pulses, at a repetition rate of ∼1 kHz. The pulse energy was in a range of 0.01–0.05 J. 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. It was found that a powder of Ni–C nanoparticles was produced. The powder consisted of carbon particles and nickel–carbon alloy particles. The latter were also coated by carbon. The carbon concentration in the Ni alloy was approximately triple of the maximum equilibrium solid solubility of carbon in nickel. The production rate of carbon was greater than the erosion rate of the Ni electrodes by factors of 2–6. The ratio of carbon production rate to electrode erosion rate decreased with the discharge energy. The size distribution of the produced particles was narrow. No particles with diameter more than 0.7 μm were observed.