Calcium Phosphate Bioceramics
Titanium Alloy or Stainless Steel Strips

Bora Mavis and A. Cuneyt Tas
Dept. of Metallurgical and Materials Engineering
Middle East Technical University
Ankara 06531

* B. Mavis and A. C. Tas, "Dip-Coating of Calcium Hydroxyapatite on Titanium Alloy (Ti-6Al-4V) Substrates," Journal of The American Ceramic Society, 83, 989-991 (2000).   (----> download: dip-ha.pdf)
* B. Mavis and A. C. Tas, "Dip-Coating of Calcium Hydroxyapatite on Titanium Alloy (Ti-6Al-4V) and Stainless Steel (316L) Substrates," "Mineralization in Natural and Synthetic Biomaterials," Materials Research Society Proceedings, Vol. 599, pp. 67-72, (Eds.) P. Li, P. Calvert, T. Kokubo, R. Levy, and C. Scheid, 2000, USA, ISBN 1-55899-507-2.
* B. Mavis and A. C. Tas, "Dip-Coating of Calcium Hydroxyapatite Bioceramics on Stainless Steel Strips," 100th Annual Meeting of the American Ceramic Society, May 3-8, 1998, Cincinnati, Ohio, USA, Oral Presentation.
* B. Mavis, "Dip-Coating of Titanium Alloy (Ti-6Al-4V) or Stainless Steel (316L) Surfaces by Calcium Hydroxyapatite (HA)," M.Sc. Thesis, METU, January 1999 (Thesis Supervisor: Dr. A. Cuneyt Tas).
* Patent Pending, Turkish Patent Institute, January 13, 1999, Ankara.


Bioceramic-coated metallic prostheses and implants were shown to display increased levels of biocompatibility
     when placed in the body environment, and these thin coatings were also shown to impede the corrosion and
     undesired metal ion transfers from the implant itself. Calcium hydroxyapatite (HA: Ca10(PO4)6(OH)2) is the
     biomaterial of choice in such coating applications.

     HA powders synthesized in our laboratory were used to prepare the viscous suspensions in the spin-coating trials
     onto titanium (Ti-6Al-4V) or stainless steel (316L) strips of dimensions, 25 x 10 x 1 mm.

     An electronically-controlled “belt-and-pulley”-type dipping apparatus, which was designed and built in our
     laboratory, was used to immerse and then withdraw the strips (25 x 10 x 1 mm) at the constant rates of 10 to 20
     mm/s from the HA-containing organic slurries. Dip-coating slurries were prepared by ultrasonification of HA powders
     mixed with appropriate amounts of natural bone gelatin, glycerol, and polyethylene glycol. Coated strips were then heated in
     the temperature range of 700 to 840°C in flowing nitrogen atmospheres.

     Sample characterization was performed by SEM (scanning electron microscopy), XRD (X-ray diffraction), and
     EDXS (energy-dispersive X-ray spectroscopy).


Fig. 1: Side view of dip-coated Ti6Al4V coupon


Fig. 2: View of the coat layer after calcinations at 800C