Pulsed Spark Discharge in Deionized Water for Nanoparticle Synthesis: Electrical Measurement and Cavitation Bubble Study

Electrical discharges in dielectric liquids are considered as an efficient and eco-friendly technique for nanoparticle synthesis via controlled erosion of electrode. Understanding of mechanisms in the discharge and plasma-electrode interactions are needed to improve the efficiency of nanoparticles synthesis. In this study, we used a homemade pulsed power supply to produce spark discharges in deionized water with different electrodes, namely Cu, Al, and Steel. Voltage and current waveforms are acquired for discharges with various inter-electrode distances and applied voltages. The data is processed to report some characteristics of the discharges, such as breakdown voltage, discharge delay, injected charge, and energy. Also, we used a fast camera to visualize the dynamics of the post-discharge cavitation bubble. A relationship has been established between the discharge characteristics and the bubble dynamics; we found that higher is the injected energy larger is the bubble radius.