Detection of nanoparticles in carbon arc discharge with laser-induced incandescence

Laser-induced incandescence measurements were conducted in the carbon arc discharge, used for synthesis of carbon nanostructures. The results reveal two spatial regions occupied by dominant populations of carbon particles with different sizes. Close to the axis of the arc, large micron size particles dominate the incandescence signal. In the arc periphery, the dominant population of nanoparticles has diameter of 20 nm. Using a heat transfer model between the gas, arc plasma and the particles, it is shown that such a drastic difference in the particle sizes can be explained by evaporation of the micron-scale particles which move across the arc plasma towards the arc periphery. It is also hypothesized that mass evaporated from the micro particles contributes to the carbon feedstock for the formation of nanostructures.

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