Nanoparticles formation and growth under the action of millisecond laser pulses in inert gas atmosphere

摘要

A model is developed for computer simulation of nanoscale particles formation by exposing the solid targets with the millisecond laser pulses of about l0~4/0~5 Wcm~2 energy flux density. The "soft" regime of vapour diffusion from a laser-heated surface of a target into an arribient atmosphere is studied. The laser flux is presumed to be low so that the surface temperature does not exceed the boiling temperature. The heat transport in the solid, liquid, and gas phases, the evaporation rate, and the vapour diffusion in the atmosphere are computed. The vapour is supercooled due to interaction with a cold ambient gas. This leads to homogenous nucleation. The rates of the nuclei formation and growth are estimated; the size distributions of the synthesised nanoparticles are presented. The influence of the operating conditions on the mean particle size is investigated.