LAUSR

ABSTRACT Scaling up the production capacity of spark discharge generated nanoparticles is crucial for their industrial application. Among various options, high-frequency spark discharge generation is a promising route as the mass production rate of nanoparticles should simply scale linearly with the spark frequency. However, reports of spark discharge generators operating above 1 kHz are scarce in the literature, as spark discharges at higher frequencies have been observed to be irregular, leading to premature spark discharges that result in a significantly lower mass production rate. In this study, we present a wire-to-plate electrode configuration that suppresses premature spark discharges during high-frequency operations above 1 kHz, and investigate the factors that contribute to the occurrence of premature spark discharges by comparing the performance of the wire-to-plate electrode configuration to those of rod-to-rod and wire-to-rod configurations. We identified that spark duration should be minimized to achieve stable spark discharge events as it correlates to the time required for the spark plasma to be completely removed from the spark zone, and found that increasing local electric field intensity and carrier gas velocity are both beneficial to achieving stable high frequency spark discharges. Lastly, using the wire-to-plate electrodes, we show that stable operation without premature spark discharges can be achieved up to 17.9 kHz and the copper nanoparticle production rate scales as expected (up to 7.6 mg/h) when premature spark discharges are eliminated during high frequency operations. Copyright © 2017 American Association for Aerosol Research