Growth Controlled by Combined Mechanisms

Most precipitation systems exhibit a metastable supersaturation zone where supersaturation is too low for nucleation to take place. As the supersaturation is increased, the point at which nucleation just begins to occur corresponds to the maximum metastable (critical) supersaturation allowable without nucleation. If crystals are present at this moment in the precipitation vessel, they grow at a maximum (critical) growth rate. 

Wey and Strong (1977a) followed this approach for each of five different monodisperse AgBr seed sizes ranging from 0.047 to 

64 microns. The temperature and the bromide ion concentration in suspension were maintained constant for all the experiments. Since the critical growth rates of different seed sizes were obtained at the same maximum metastable supersaturation condition, the effect of supersaturation can be eliminated from the correlation between growth rate and crystal size. Furthermore, the maximum metastable supersaturation can be estimated when comparing the experimental results with growth models. 

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