Synthesis and Characterization of Copper/Silver Nanoparticles by the Electromagnetic Levitation Gas Condensation Method

1. Abstract: Copper nanoparticles of high purity (Cu NPs ), copper oxide nanoparticles (Cu x O NPs ), copper/silver bimetallic nanoally (Cu/Ag NPs ), and multiphase nanocomposites(Cu x O/Ag NPs ) were obtained through the Electromagnetic Levitation Gas Condensation (ELGC) process.Due to the distinct vapor pressures of the elements, analysis revealed that the silver concentration in the synthesized bimetallic nanoalloy was enriched compared to the initial precursor mixture. Structural and XRD analyses demonstrated lattice parameter modulations driven by atomic size mismatch: dissolution of Cu into the Ag lattice caused lattice contraction. In the oxidized Cu x OAg NPs system, clear phase segregation occurred, yielding coexisting metallic Ag and copper oxide phases. Pristine Cu exhibited a crystallite size of 46 nm, which shifted to 51 nm in Cu 2 O and 37 nm in CuO NPs . The as-synthesized Cu/Ag NPs displayed refined crystallite sizes of 21 nm (Ag-rich) and 27 nm (Cu-rich), whereas the multiphase Cu x O/Ag NPs nanocomposite comprised crystallite domains of 47 nm (Ag NPs ), 19 nm (Cu 2 O NPs ), and 28 nm (CuO NPs ). Electron microscopy confirmed spherical particle morphologies with average TEM diameters ranging from 71 to 102 nm (93–201 nm by SEM), showing that the controlled introduction of oxygen promotes oxidation and influences particle growth. These results demonstrate the high efficacy of ELGC in tailoring phase architecture and nanoscale dimensions in immiscible and partially miscible metallic systems.