The effect of target size on α-Fe nanoparticle preparation by pulsed laser ablation

Two methods of preparing Fe nanoparticles at atmospheric pressure were conducted using pulsed laser ablation of a 0.5-mm-diameter Fe wire and a bulk Fe target. Passivated α-Fe nanoparticles covered with a shell of γ-Fe2O3 were prepared at different process parameters. The influences of average laser power, repetition rate, pulse duration and carrier-gas pressure on the mean particle size for two laser ablation methods were investigated, respectively. The results show that the target size has a large effect on the nanoparticle preparation though we have the same range of laser process parameters. Except the carrier-gas pressure, the influence of the laser parameters on the mean particle size is almost opposite for the two laser ablation methods. Besides, the ablation mechanisms were discussed to understand the variation of mean particle sizes with target size.