Factors that influence the adherence of biovitroceramic coatings on titanium

In order to manufacture ceramic coatings on metallic substrates with medical applicability, a compromise has to be made between adherence, mechanical resistance and bioactivity. Biovitroceramic layers to satisfy all these requirements are extremely difficulty to develop. The goal of this contribution is to employ a simple technique like enamelling for making biocompatible and bioactive coatings with improved mechanical properties and very good adherence onto metallic substrates made of titanium samples. One important factor for a good adherence is the value of the thermal expansion coefficient of the ceramic coating to be closed to that of the metallic substrate. Once this achieved by establishing an adequate ceramic composition, there remain other factors that contribute to a good adherence such as metallic surface pretreatment. The surface was processed by Al2O3 Powder (125 mu m) blasting, degreased with acetone in an ultrasonic device and immersion in phosphoric acid. The (Na2O-K2O-Li2O-CaO-MgO-SiO2-B2O3-TiO2-P2O5) biovitroceramic coating - titanium interface was examined by means of optical microscopy and electronic microscopy. The coating adherence to the metallic substrate was evaluated qualitatively by Vickers microhardness tests at the interface.