Graded glass coatings for Co-Cr implant alloys

• Published in: Journal of materials science 2005-05, Vol.40 (9-10), p.2499-2503
• Main Authors: FUJINO, S, TOKUNAGA, H, HATA, H, SAIZ, E, TOMSIA, A. P
• Format: Article
• Language: English
• Subjects: Adhesion tests; Alloys; Applied sciences; Biocompatibility; Biomedical materials; Body fluids; Chromium; Coatings; Cobalt base alloys; Composition; Enameling; Exact sciences and technology; Glass coatings; Hardness tests; Hydroxyapatite; In vitro methods and tests; Indentation; Materials science; Metals. Metallurgy; Nonmetallic coatings; Production techniques; Surface treatment; Surgical implants; Thermal expansion
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-005-1982-z

A graded glass coating for Vitallium®, a Co-Cr alloy, has been prepared using a simple enameling technique. The composition of the glasses 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 25 and 60 μm. Coatings fired under optimum conditions do not delaminate during indentation tests of adhesion. Excellent adhesion to the alloy has been achieved through the formation of 100 nm thick interfacial chromium-oxide (CrOx) layers. The graded glass (consisting of BIG and 6P50 layers) can be successfully coated to a Co-Cr alloy, and forms hydroxyapatite (HA) on the coating surface when immersed in a simulated body fluid (SBF) for 30 days.