In this work, the synthetic Hydroxyapatite (HAP) was studied using different preparation routes to decrease the crystal size and was studied the temperature effect on the nano-sized hydroxyapatite crystallization. X-ray diffraction (XRD) analysis indicated the all samples were composed by a crystalline HAP phase and another amorphous part.

1. SCANNING VOL. 30, 3 (2008) 265
heat resistant materials that won’t degrade at these
temperatures.
In this work, we present a study which determined
swiping efficiencies of different collection traps by
swiping a variety of surfaces with particulate
contamination. The swiping was completed in a
repeatable fashion, using a slip peel instrument which
eliminated variability that would otherwise exist with
human screeners. Automated fluorescence
microscopy was used to visualize and count all of the
particles on the surfaces and traps, before and after
swiping. Issues such as calibration, image resolution,
and particle counting associated with this method
will be discussed.
Results indicate that there are significant
differences in the collection efficiencies between the
two types of traps studied, muslin cloth and Teflon
coated fiberglass. It was also found that increasing
the applied force during swiping offers minimal
improvements for particle collection efficiencies,
regardless of the collection trap being used. Future
efforts will focus on extending this method to vehicle
swiping by utilizing this automated microscopy
technique for quick and easy particle counting.
Acknowledgement:
The Department of Homeland Security Science and
Technology Directorate sponsored this work under an
interagency agreement with the National Institute of
Standards and Technology.
Influence of Thermal Treatment on the
Morphology of Nanostructured Hydroxyapatite
F. L. LEITE
2,41
,M. MIR
1
, A. M. ROSSI
3
,
E. L. MOREIRA
3
, Y. P. MASCARENHAS
2
,
P. S. P. HERRMANN
4
1
Dept de Ciências Exatas, Universidade Federal de
Alfenas (Unifal-MG), Alfenas, MG, Brazil;
2
Instituto
de Física de São Carlos, Universidade de São Paulo
(USP) – São Carlos, Brazil;
3
Centro Brasileiro de
Pesquisas Físicas (CBPF) – Rio de Janeiro, Brazil;
4
Embrapa Instrumentação Agropecuária – São
Carlos, Brazil.
In this work, the synthetic Hydroxyapatite (HAP)
was studied using different preparation routes to
decrease the crystal size and was studied the
temperature effect on the nano-sized hydroxyapatite
crystallization. X-ray diffraction (XRD) analysis
indicated the all samples were composed by a
crystalline HAP phase and another amorphous part.
The sample with greater quantity of amorphous phase
corresponding up to 40% of sample total mass was
studied. From the nano-sized hydroxyapatite powder
were separated five samples and each sample was
heated at 300, 500, 700, 900 and 1150
o
C respectively.
All samples were characterized by XRD and refined
using the Rietveld method. In all cases, the crystals
present an anisotropic form, being larger in the [001]
direction. We observed that the particle size grows
continuously with the heated temperature and the
eccentricity of the ellipsoidal shape changes from
2.75 at 300
o
C to 1.94, 1.43, 1.04 and 1.00
respectively at 500, 700, 900 and 1150
o
C. In order to
better characterize the nano-sized hydroxyapatite
powder, thin layers were prepared and characterized
using atomic force microscopy (AFM). The analysis
of the surface topography of HAP particles, deposited
on a mica substrate, shows that length of particles
also increased with the temperature, which
aggrement with XRD results. The presence of
aggregates on the surface was a common
characteristic irrespective of the type of substrate and
deposition. At larger areas, it was estimated that
some of the aggregates were less than 2300 nm in
size for samples heated on 1150
o
C (see Fig 1).
Acknowledgements: Thanks to Fapesp, CNPq and
USP
Keywords: Hydroxyapatite, XRD, AFM.
1
Corresponding Author: leite@cnpdia.embrapa.br
Figure 1. Surface topography of a HAP film eposited on
Mica.