Fabrication and Characterization of Bioactive Glass Coatings on Co-Cr Implant Alloys

Abstract

Silicate glass coatings on Vitallium^®, a Co-Cr alloy were prepared using a simple enameling technique. The composition of the glasses in the SiO₂-Na₂O-K₂O-MgO-CaO-P₂O₅ system has been tailored to match the thermal expansion of the alloys. The optimum glass composition and firing conditions (temperature and time) needed to fabricate homogeneous coatings with good adhesion to the alloy were determined. The final coating thickness ranged between 40 and 60 μm. Coatings fired under the optimum conditions do not delaminate during indentation tests of adhesion. Excellent adhesion to the alloy has been achieved through the formation of 150 nm thick interfacial layers (CrOx). The silicate glass can be successfully coated to Co-Cr alloy and formed hydroxyapatite on the glass surface when immersed in a simulated body fluid (SBF) for 30 days.