EFFECTS OF ETHYLAMINE ON THE CRYSTAL GROWTH OF HYDROXYAPATITE

Abstract

Plate-like hydroxyapatite (HAp) crystals whose preferential crystal plane is the a-plane were obtained by hydrothermal treatment in the presence of ethylamine. The HAp precursor slurry was treated hydrothermally with various amount of ethylamine at 200 °C for 5 hours. TEM revealed that the products synthesized with 5 wt% or more ethylamine are plate-like crystals, in contrast the products obtained without ethylamine has a granular or rod-like shape. XRD patterns of plate-like crystals orientated preferentially indicate that the grown face of the plate-like crystals is a-plane of HAp. It can be suggested that ethylamine captured PO₄^3- ions in the solution by chelation and retarded a supply of PO₄^3- to HAp nuclei and consequently crystal growth along a particular axis was inhibited.