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V. R. ESTRELA-L’OPIS and T. I. BORODINOVA
«Kinetics of Gold Single Crystals Growth in Water Solution of Chloroauric Acid and Polysaccharides»
487–496 (2008)

PACS numbers: 81.10.Dn, 81.16.Fg, 81.20.Fw, 82.35.Pq, 82.70.-y, 87.83.+a

Earlier, we obtained nano- and microcrystals of gold by a method similar to Faraday’s method (reduction of ions of gold from aqueous solutions at normal conditions). These crystals have a shape of flat regular triangles, hexagons and triangles with symmetrically cut vertices. Optical-microscopy investigation of the kinetics of gold single-crystals’ growth within the period of 3–26 hours is carried out. As shown, during the period from 3 to 6 hours, the size of a crystal is increasing under the linear law. Thus, the average rate of crystal growth is ??1 micron/hour ???2.7 A/s, i.e. about one monolayer of gold atoms is settled each second. Gold crystals in amount of 1?106 сm?1 with an average linear size of 5 microns are formed for 8 hours in the system. Thus, concentration of all crystals, which are observable (а???100 nm) in a dark field of an optical microscope (?252), is 3?106 сm?3. The analytical investigations show that up to 7% of gold from the solution passes into single crystals for 8 hours. It is possible to select three stages in kinetics of gold-crystal growth: at an initial stage, the crystals grow under the parabolic law, then the stage of linear crystal growth follows and, at last, saturation occurs after 6–8 hours of crystal growth.