BIOACTIVE COATINGS OF GLASS-CERAMICS ON METALS

To combine the mechanical properties of high-strength base metals with the biological properties of bioactive materials, coatings of BIOVERIT(R) glasses and glass-ceramics on CoCr alloys and titanium have been produced. Different kinds of coating processes have been used: dipping, sputtering, plasma spraying, sintering and pasting. Dipping and pasting seem not to be suitable to produce layers because of cracks and low adhesion strength of the coatings (dipping) and the limitations in relation to the implant shape and the thickness of the layers (pasting). Using sputter techniques it is possible to produce dense layers (<10 mum) with a high adhesion strength. Plasma spraying resulted in layers with a thickness of 50 to 300 mum, but during the plasma spraying process there is a partial evaporation of the highly volatile glass components. Sintering processes are very suitable to produce layers with a high adhesion strength; these layers are long-term stable in simulated body fluid.