Fig. 9
From: Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids
On the mechanism of particles formation during spark erosion. a The potential difference between positively and negatively charged granules of a material induces the arc discharge through the small gap between them. Arc plasma channel 1 produces a lot of heat which melts and evaporates the material. Around the channel, the gaseous bubble 3 appears, by surface of which those evaporated constituents are condensed. The jets of melt are ejected from the pulls of molten material 2 on the surface of cathode and anode. Liquid jets are subsequently transformed in micron-sized droplets, which are quenched in situ into the coolant liquid 4. b Illustration of quenching in situ the molten droplet, which is moving through the cryogenic liquid (argon) surrounded by the bubble of gaseous argon and vapors of alloy components (Ti, Ni, and Hf in that case)