Kinetics of Copper-Silver Particle Formation in an Aqueous Solution

The kinetics of metal particle formation from a mixture of aqueous copper nitrate and silver nitrate solutions was studied at Ag : Cu ratios of 1 : 0 to 1 : 0.21. A shift of the silver sol absorption peak and the appearance of a copper peak were observed at 15-21% Cu. The absorption spectra show that the weighted-mean radius of the particles passes through a maximum in the course of their formation and then, because of the appearance of new crystallization centers, decreases to 4.0-4.5 nm. An analysis of the particle-growth kinetics at 298-323 K and of the spectral data and the results obtained by X-ray spectroscopy microanalysis indicates that mixed AgxCuy particles have a composition close to the composition of the starting solution and that copper-silver nucleation is less probable than silver nucleation.