Sweegers C, Boerrigter SXM, Grimbergen RFP, Meekes H, Fleming S, Hiralal IDK, Rijkeboer A
 
Abstract:
The morphology of gibbsite, gamma-Al(OH)(3), crystals is predicted on the basis of a complete connected net analysis.
It turns out that the morphology cannot be explained on the basis of the attachment energy, Instead, it is shown by a
Monte Carlo algorithm based on a 2D nucleation model, that the edge (free) energy of the flat faces is the relevant
parameter that determines the growth morphology. The algorithm reveals that the morphological importance of the
faces follows the sequence: {112}, {11 (2) over bar} similar to {101}, {10 (1) over bar} < {200} < {110} much less
than {002}. At zero driving force, gibbsite has a hexagonal morphology with {002} basal faces, {200} and {110} side
and {101}, {10 (1) over bar}, {112} and {11 (2) over bar} chamfered faces. At higher driving forces, the chamfered
faces disappear first, followed by the {200} faces. This corresponds well to our experimental results and is explained in
terms of the energies involved in the formation of 2D nuclei at the various surfaces. Thus, the various morphologies
observed for gibbsite crystals depending on the driving force for crystallization can be explained.