GROWTH-KINETICS OF HYDROXYAPATITE CRYSTAL REVEALED BY ATOMIC-FORCE MICROSCOPY

The growth process of the {10 ($) over bar 10} face of synthesized hyd roxyapatite single crystal under physiological conditions were first i nvestigated by in situ atomic force microscopy (AFM). It was confirmed that the growth proceeded by both simple flow of steps which appeared on the wall of an etch pit and a two-dimensional nucleus. Step veloci ties were in the order of 10(-3) nm/s and independent of the step heig hts. This means that the bulk and/or surface diffusion of a growth uni t is not the rate-determining process. Microscopic Raman spectroscopy of grown crystals showed that the newly grown layer has a poorer cryst allinity than the seed crystal.