Optical properties of hydroxyapatite obtained by mechanical alloying
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 63 (9):
1745-1757 (2002)DOI: 10.1016/S0022-3697(01)00262-1
Abstract
Calcium phosphate based bioceramics, mainly in the form of
hydroxyapatite (HA), have been in use in medicine and dentistry for the
last 20 years. Applications include coatings of orthopaedic and dental
implants, alveolar ridge augmentation, maxillofacial surgery,
otolaryngology, and scaffolds for bone growth and as powders in total
hip and knee surgery. These materials exhibit several problems of
handling and fabrication, which can be overcome by mixing with a
suitable binder. In this paper, mechanical alloying has been used
successfully to produce nanocrystalline powders of HA using five
different experimental procedures. The milled HA were studied by X-ray
powder diffraction, infrared and Raman scattering spectroscopy. For four
different procedures, HA was obtained after a couple of hours of milling
(on an average, 20 h of milling depending on the reaction procedure).
The XRD patterns indicate that the grain size is within the range of
29-103 nm. This milling process, used to produce HA, presents the
advantage that melting is not necessary and the powder obtained is
nanocrystalline with extraordinary mechanical properties. The material
can be compacted and transformed in solid ceramic samples. The high
efficiency of the process opens a way to produce commercial amount of
nanocrystalline HA. Due to the nanocrystalline character of this powder,
their mechanical properties have changed and for this reason a pressure
of 1 GPa is enough to shape the sample into any geometry. (C) 2002
Published by Elsevier Science Ltd.