Inhibition of growth in solid solution–aqueous solution systems byudnon-incorporating impurities

摘要

Crystal growth inhibition by non-incorporating impurities has been described and quantified since 1958 byudthe so-called step pinning model by Cabrera and Vermilyea [1]. In the original model, as well as in its recentudimprovements by Weaver et al. in 2006 and 2007 [2,3], only the inhibition by the adsorption of impurities onudcrystal surfaces with fixed compositions is considered. However, most of the crystals found in nature are solidudsolutions with more or less wide chemical variability. Therefore, in order to provide more realistic models ofudcrystal growth inhibition in natural systems, it is fundamental to study in detail the inhibition of surfaces ofudsolid solutions by non-incorporating impurities. In this paper, the Cabrera–Vermilyea model has beenudgeneralised for the case of growth inhibition in solid solution–aqueous solution (SS–AS) systems. Thisudgeneralisation was made by considering that supersaturation and the physicochemical properties of the solidudsolutions are functions of the solid composition. The main implication of the model is that a progressiveudinhibition of growth of a solid solution by increasing the concentration of an adsorbed impurity results inudcompositional changes on the growing surfaces.