Synergistic Effect of Plasma and Laser Processes in Liquid for Alloyed-Nanoparticle Synthesis

Abstract

$\mathrm{Cu}$-$\mathrm{Ag}$-alloy nanoparticles (NPs) are synthesized from micropowders of pure $\mathrm{Cu}$ and $\mathrm{Ag}$ by two consecutive nonequilibrium processes based on plasma and lasers in liquids. The plasma process reduces the size of the particles forming the initial powders from micrometer size to nanometer size, at which the laser fluence is sufficient to melt them, making alloying possible. Measurements at macroscopic (solution absorption), microscopic (scattering of individual NPs), and nanoscopic (electron microscopy) scales confirm alloying of NPs and homogenization of size and composition. This has a noticeable effect on the final colloidal solution, which absorbs yellow-orange light (550--600 nm) after laser treatment. With a synthesis rate of 360 mg/h, this process opens up possibilities for nonequilibrium nanometallurgy of functional NPs.