RESUMEN
Cu-Ag core-shell nanopowders have been prepared by ultrasound-assisted electrochemistry followed by a displacement reaction. The composition of the particles has been determined by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The XRD patterns versus time displacement show that higher are the silver peaks intensities, weaker are the copper ones. That exhibits the progressive recovering of copper by silver. EDX results and quartz crystal microbalance results indicate that various reaction mechanisms are implied in this process. Transmission electron microscopy (TEM) points out variable nanometric diameter grain and some small agglomerates. Elemental mapping obtained by electron energy-loss spectroscopy (EELS) underlines the core-shell structure.
RESUMEN
The copper electroless displacement by silver has been studied in the absence of cyanide ions. The investigations have been carried out using a quartz crystal microbalance, and it was shown that the electroless displacement was plainly diffusion-controlled during 1 min. The electrochemical deposition of Cu-Ag multilayers has been achieved using two methods: by displacement reaction and by alternated applied potentials.
