In-flight coating of Ag nanoparticles with Cu.

AgCu Janus nanoparticles (NPs) were prepared by coating of Ag NPs in flight. The Ag NPs, produced by a gas aggregation source, were coated with Cu during their flight through a tubular magnetron (TMG). Their structure and chemical composition were studied to establish their dependence on the TMG's operational parameters. The main focus was the influence of the TMG's current and magnetic field. It was found that trapping of the NPs occurred at a certain combination of these two parameters. When trapping happened, the size of the NPs and their Cu content increased significantly. We have demonstrated that we can vary the composition of the NP's produced from pristine Ag from perfect Janus NPs with a Ag/Cu ratio of 50/50, to almost-pure Cu NPs with tiny Ag inclusions. [ABSTRACT FROM AUTHOR]