Imaging of crystal growth-induced fine surface features in zeolite A by atomic force microscopy

Atomic force microscopy was used to examine the crystal growth-induced fine surface features on the I 10 01 faces of zeolite A. Features reported previously (terraces with ledges similar to1.2 nm in height, and small pyramidal structures composed of layers with thickness of similar to1.2 nm) as well as features not reported previously (polygonized growth spirals with step height of similar to1.2 nm) were observed. These features suggest that the layer growth of zeolite A can occur by both a "perfect" crystal two-dimensional nucleation mechanism, and by an "imperfect" crystal spiral growth mechanism, The origin of the observed small pyramidal structures and growth spirals as well as the mechanisms of their formation are hypothesized, (C) 2002 Elsevier Science Inc. All rights reserved.