Effect of Alkali and Heat Treatment on Biomimetic HA Coating on Ti6Al4V

Document Type : Research Article



In this study, time of calcium phosphate formation on Ti6Al4V alloy with or without alkali and heat treatments was investigated. Specimens were soaked in 0, 5, 10 M solutions of NaOH at temperatures of 60 or 80 °C for 24, 72 h. Their surfaces were characterized using scanning electron microscopy and thin film X-ray diffraction. It was found that optimum condition is 72h soaking in 5 M NaOH in 80 °C. Specimens treated under these optimum conditions were subsequently heat-treated at 500, 600, and 700 °C for 1h in order to consolidate the sodium titanate hydrogel layer. With heat treatment at 600 °C for 1h and then soaking in simulated body fluid (SBF), apatite formed within 3 days. But there were no signs of apatite formation in control samples (without alkali and heat treatment) up to 7 days soaking in SBF. So, it was concluded that alkali-heat treatment is an effective way for accelerating apatite formation and the optimum condition is 72 h soaking in 5 M NaOH solution at 80°C and then heat treatment at 600 °C resulted for 1 h.


[1]     L.L. Hench, “Bioceramics: from concept to clinic,” J. Am. Ceram. Soc, vol.74, pp. 1487– 1510, 1991.
[2]     A. Ravaglioli, A. Krajewski, “Bioceramics: Materials, Properties, Applications,”Chapman & Hall, London, pp. 46 – 60, 1992.
[3]     M.J. Filaggi, N.A. Coombs, R.M. Pilliar, “Characterization of the interface in the plasma-sprayed HA coating/Ti-6Al-4V implant system,” J. Biomed. Mater. Res. vol. 25, pp.  1211– 1219, 1991.
[4]     K. Hayashi, T. Mashima, K. Uenoyama, “The effect of hydroxyapatite coating on bony ingrowth into grooved titanium implants,” Biomaterials, vol. 20, pp. 111 – 119, 1999.
[5]     M. Wei, A.J. Ruys, B.K. Milthorpe, C.C. Sorrell, “Solution ripening of hydroxyapatite nanoparticles: effects on electrophoretic deposition,” J. Biomed. Mater. Res. vol. 45, pp. 11 – 19, 1999.
[6]     H. Monma, “Electrolytic depositions of calcium phosphates on substrate,” J. Mater. Sci. vol.29, pp. 949– 953, 1994.
[7]     F. Barrere, P. Layrolle, C.A. Van Blitterswijk and K. De. Groot, “Biomimetic Calcium Phosphate Coatings on Ti6Al4V: A Crystal Growth Study of Octacalcium Phosphate and Inhibition by Mg+2 and HCO3-,” Bone vol.25, No. 2, pp. 107–111,1999.
[8]     Kokubo, T., Kushitani, H., Abe, Y., and Yamamuro, T. “Apatite coating on various substrates in simulated body fluid,” Bioceramics, vol. 2, pp. 235–242,1989.
[9]     H.M. Kim, F. Miyaji, T. Kokubo, T. Nakamura, “Bonding strength of bonelike apatite layer to Ti metal substrate,” J. Biomed. Mater. Res. vol. 38 , pp. 121–127, 1997.
[10]  H.B. Wen, Q. Liu, J.R. de Wijn, K. de Groot, F.Z. Cui, “Preparation of bioactive microporous titanium surface by a new two-step chemical treatment,” J. Mater. Sci. vol. 9, pp. 121– 128, 1998.
[11]  T. Kokubo, “Apatite formation on surfaces of ceramics, metals and polymers in body environment,” Acta Mater. vol. 46,  pp. 2519–2527,1998.
[12]  Kim H.M., Kokubo .T, awashita . M.”Novel bioactive materials with different mechanical properties,” Biomaterials,vol. 24, pp.  2161– 2175, 2003.
[13]  Teixeira R.L.P, Godoy G.C.D, Pereira M.M.”Calcium Phosphate Formation on Alkali-Treated Titanium Alloy and Stainless Steel,” Materials Research, vol.7, pp. 299-303, 2004.
[14]  Yan W.Q , Nakamura T, Kawanabe K, Nishigochi Sh., Oka M, Kokubo T.”Apatite layer-coated titanium for use as bone bonding implants,” Biomaterials, vol. 18, pp. 1185-1190, (1997). 
[15]  F. Barrere, M. Snel, C.A.Blitterswijk, K. Groot, P. Layrolle, “Nano-scale study of the nucleation and growth of calcium phosphate coating on titanium implants,” Biomaterials, vol. 25, pp. 2901–2910, 2004.
[16]  I. Hofmann, L. Müller, P. Greil, F.A. Müller, “Calcium phosphate nucleation on cellulose fabrics,” Surface & Coatings Technology , vol.201, pp. 2392–2398, 2006.