Hydroxyapatite (HA) biocoatings were obtained using two different deposition methods (sol-gel and sputtering). The depositions were performed on bare silicon or covered with a TiO₂ buffer layer. Comparison of physico-chemical properties between different samples prepared by sputtering and sol-method, as well as between films deposited with and without TiO₂ buffer layer is a main subject of this paper. The microstructural, chemical and optical characterizations of the films were performed by IR, XPS, UV-VIS Absorption and Ellipsometric Spectroscopies. The studied HA/Si films are highly transparent and colorless, owing to low refractive index of hydroxyapatite (1.556 at wavelength 590 nm, as estimated from ellipsometric data). Interference color, which depends on refractive index and thickness, was slightly observed increasing film thickness from 160 to 2500 nm. Ca/P atomic ratio of 1.7 (specific for HA) was evaluated from XPS spectra. Silicon signal derived from substrate or any other signals from impurities except carbon from surface were not observed. Similar FTIR spectra recorded on sputtering and sol-gel films were obtained. FTIR measurements showed two peaks from 550-600 cm^-1 and 1000-1200 cm^-1 which are attributed to the major absorption modes associated with the presence of phosphate (S. W. Russell et al., J. Am. Ceram. Soc. 79 (1996), 837). Films annealed at 400-550⁰C showed a band at 1600 cm^-1 and one more faint at 861 cm^-1 related to the CO₃^2- ions. The OH^- group was detected by XPS analysis after O1s line deconvolution. It was found that OH^- group presents a relative concentration of about 15% from the total amount of oxygen. Although the investigated films show similar properties with previous published results, future improvements are necessary to reduce the carbon contamination due to organic residuals and to increase the stoichiometry of the films.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/11890 must be provided.

1. New concepts for ZnTe-based microcavities
2. Hydroxiapatite films on Ti and TiO₂ for biological applications
3. Structural and morphological study of hydroxyapatite grown by chemical methods on different substrates
4. Raman spectra intensity as a function of the penetration depth of the visible light in the in-situ grown YBCO films
5. TiON as multifunctional nanostructured film
6. SBF studies of Bioglass Nanostructured Thin Films obtained by pulsed laser deposition or magnetron sputtering: a comparative study