The effect of circuit resistance on the particle output of a spark discharge nanoparticle generator

The present study investigates how systematic variation of the resistance of the discharge loop influences the nanoparticle output and the electrode erosion of spark discharge generators (SDGs). The size distribution of the nanoparticles, as well as the mass loss of gold electrodes was recorded while varying the total resistance of the discharge loop. It was demonstrated that the characteristics of the aerosol nanoparticles produced by SDGs as well as the erosion rate of electrodes strongly depend on the total resistance even at small values. It was found that by increasing Rtotal from 0.7 Ω to 6 Ω, the modal diameter of the gold particles decreased from 39 nm to 16.5 nm with the concomitant decrease of the erosion rate. Our data allowed concluding that a fair part of the few ohms of total resistance typical to SDGs can easily originate from the electric circuit which affects the particle output. This also means that in addition to the usual control parameters, the total resistance should also be monitored in an SDG, conveniently via monitoring the current, for the purpose of maintaining stable and reproducible NP production. Moreover, circuit resistance can even be considered to be a practical control parameter, if certain size particles are to be produced by an SDG.