Submicron particles synthesis by laser evaporation at low power density: anumerical analysis

A model for submicron particles formation by laser evaporation in ambient g as atmosphere is proposed. Heat transport in the target, evaporation, vapou r diffusion in the ambient gas, and kinetics of nucleation and particles gr owth are considered. The diffusion regime of evaporation is studied. Submic ron particles formation by millisecond laser pulses of about 10(4)-10(5) W/ cm(2) energy density flux is analysed. The nuclei formation and growth rate s are estimated and size distributions of the particles are calculated. The mean particle size decreases with the ambient gas pressure. The spatial se paration of nuclei formation and the particles growth processes with a defi ciency of condensation centres ensures conditions for a nearly uniform grow th which results in narrow particle-size distribution. (C) 2000 Elsevier Sc ience B.V. All rights reserved.