Modeling of the laser pyrolysis process by means of the aerosol theory: Case of iron nanoparticles

摘要

Laser pyrolysis is a technique in which the interaction between a laser and a gaseous flow of precursors is used to obtain homogeneous nanoparticles. One of the main advantages of using this method is that it generates ultrafine powders in a continuous way with narrow particle-size distribution. The absence of surfactants of potential toxicity makes the product ideal for the preparation of colloidal dispersions for use in biomedical applications. It is of particular interest in the case of the iron nanoparticles due to their high magnetic response. In this paper, a simple coagulation model adapted from the theory of aerosol formation is successfully used in the modeling of the production of iron nanoparticles. The experimental conditions needed to maximize the productivity were obtained as a function of particle size. The main conclusion is that for the production of "large" particle-size nanomaterials (>20 nm), the ruling factors are the pressure and the carrier gas flux. However, the production of small particle-size nanomaterials (<20 nm) depends on the evaporation temperature of the precursor.