Page 320 - 00. Complete Version - Progress Report IPEN 2014-2016

320 Materials and Nanotechnology | Progress Report

Development of x-ray ta-tricalcium phosphate (ο-TCP) and biphasic
diffraction methodologies of phosphate nanopowders were synthesized
materials characterization by co-precipitation method and their crystal
structures and fluorescence properties were
X-ray diffraction is a fundamental phenome- investigated depending on the pH of the start-
non resulting from the interaction of the pho- ing solution. In the range of pH 6–10, HA and
tons and the atoms revealing the crystal struc- ο-TCP phases coexist. The ο-TCP proportion
ture of the materials. This technique is widely increased as the pH of the solution decreased,
used to study the microstructure evolution while HA yields decreased. At pH below 6,
that takes place during various processes in- monophasic ο-TCP powder was obtained af-
cluding thermomechanical processing of ma- ter thermal treatment. In particular, HA and
terials. The continuous evolution of materials ο-TCP can be used as luminescent materials
development, in the scientific aspect as well when activated by Eu3+ions in substitution
as for industrial applications, also implies in a of Ca2+ ions. Herein, the Eu3+ ions doped HA
continuous evolution of the methodologies of and ο-TCP phase composition were analyzed
materials characterization. The following ap- in order to investigate the fluorescence emis-
plication was performed in the CCTM´s x-ray sion of the HA, ο-TCP and biphasic compounds.
diffraction laboratory. Eu-doped HA exhibited a red-orange emission
at 575 nm with several minor peaks at 610–
Nanomaterials: 640 nm, while Eu-doped ο-TCP had an unex-

pected strong red emission at 610–620 nm
Nanostructured coatings have been used to and a secondary band at 590–600 nm. In fact,
protect components exposed to severe ser- the Eu:ο-TCP integrated emission area is al-
vice conditions. High energy milling is widely most 20-fold higher than Eu:HA for the same
used to produce nanocrystalline feedstock of europium ion concentration. These results
coating materials such as chromium carbide demonstrate the potential of Eu:ο-TCP as bio-
and tungsten carbide. During the high energy marker for medical applications, as drug re-
milling of Cr3C2–25(Ni20Cr) powder, severe lease and targeting based on their lumines-
plastic deformation takes place. A small part cent properties.
of the energy spent in this process is stored in
the crystal lattice as deformation energy. The A nanosized magnesium-substituted beta-tri-
crystallite size and microstrain in nanocrys- calcium phosphate (Mg:ο-TCP) was synthe-
talline Cr3C2–25(Ni20Cr) powders milled for sized by an aqueous precipitation method, at
different times were determined by X-ray dif- room temperature, in one single step. The nov-
fraction measurements. el and stable Mg:ο-TCP resulted in a crystal-
line and spherical nanoparticles (diameter of
Calcium phosphates, including hydroxyapa- approximately 20nm), with mesoporous struc-
tite [HA, Ca10 (PO4)6(OH)2] and beta-trical- tures and a high specific surface area (about
cium phosphate [ο-TCP, Ca3(PO4)2], are the 574m2/g). These special characteristics make
main mineral component of bone tissue and this novel crystalline mesoporous Mg: ο-TCP
teeth. The synthetic calcium phosphates are nanoparticles ideal candidates for drug deliv-
of special interest in medicine because of their ery system and a promising non-viral vector
biocompatibility, bioactivity and non-toxici- for gene therapy.
ty. Europium-doped hydroxyapatite (HA), be-

Instituto de Pesquisas Energéticas e Nucleares