FTIR AND RAMAN-SPECTRA OF BIOCERAMICS OBTAINED BY AN INNOVATIVE METHOD

Bioceramic coatings with defined chemical composition and structure are often needed to satisfy specific biocompatibility properties in the prosthetic field. An example is hydroxyapatite (HA) for coatings, which, according to the Standard Specifications of the ASTM, must be crystalline and have a stoichiometric molar ratio Ca/P=1.67 with a 95% minimum amount of HA. Since the methods (plasma flame spray, ion beam sputtering, etc.) to obtain bioceramic coatings, in particular those for HA, induce changes in the chemical composition, structure and physical state of the coating, an alternative and innovative method (the so-called polymeric route) which provides bioceramic coatings under less severe conditions with controlled chemical composition and structure, was used in this work. The method was applied to the preparation not only of HA, but also, for the first time, of high-temperature-melting calcium phosphate bioactive glasses with a molar ratio CaO/P2O5=1 (calcium metaphosphate) and in the range 1-1.5 (calcium oligophosphates). The different phases of the process were characterized by vibrational FTIR spectra. The structure of the final glasses were a Iso stud led by Raman spectroscopy and com pared with the spectra of the same products obtained by the traditional melting method.