Abstract
in this paper, we did a study on the structural and electrical
properties of bioceramic hydroxiapatite (HA) thick films. The films were
prepared in two layers using the screen-printing technique on Al2O3
substrates. Mechanical alloying has been used successfully to produce
nanocrystalline powders of hydroxyapatite to be used in the films. We
also look for the effect of the grain size of the HA in the final
properties of the film. The samples were studied using X-ray diffraction
(XRD), scanning electron microscopy (SEM), energy-dispersive
spectroscopy (EDS), infrared and Raman scattering spectroscopy and
electrical measurements. We did a study of the dielectric permittivity
and the loss of the films in the radio-frequency of the spectra. The
X-ray diffraction patterns of the films indicate that all the peaks
associated to HA phase is present in the films. One can notice that, for
all the films there is a decrease of the DC (dielectric constant) with
the increase of the frequency. The values of the dielectric constant of
the films are in between 4 and 9 (at 1 kHz), as a function of the flux
concentration. The loss is decreasing as we increase the frequency for
all the films. These results strongly suggest that the screen-printing
HA thick films are good candidates for applications in biocompatible
coatings of implant materials. (c) 2005 Elsevier B.V. All rights
reserved.
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