In situ studies of different growth modes of silver crystals induced by the concentration field in an aqueous solution

An in situ observation of silver hierarchical crystal growth in a Zn/AgNO₃ (aq.) replacement reaction system revealed that the morphological evolution of silver crystal strongly depended on the change of the silver ion concentrations. With the increasing concentration, the morphologies of the silver crystal transformed from loose fractal (LF) to dense branch morphology (DBM) and even to dendrite. The concentration field was in situ monitored using a Michelson interferometer during the reaction and the profile of the concentration field was studied based on experimental observation. The crystals morphology transform was induced by different growth modes. At low concentration, the growth mode was ion diffusion limited growth and at the high concentration the growth mode was protuberant growth which was decided by reaction limitation.