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 (HA) 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, scanning electron microscopy (SEM), energy-dispersive
spectroscopy (EDS) and electric 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 (XRD) patterns of the films
indicates 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 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 material concentration. The loss is decreasing as we
increase the frequency for all the films. These results strongly
suggests that the screen-printing HA thick films are good candidates for
applications in biocompatible coatings of implant materials but also for
the insulating materials of electronic circuits and dielectric layer in
bio-sensors. (C) 2003 Kluwer Academic Publishers.
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