Hydroxyapatite Toughened by Silver Inclusions

Abstract

Three kinds of processing procedure, including conventional sintering, hot-isostatic pressing, and their combination, were explored to prepare hydroxyapatite-silver composites with high density and improved ceramic-metal interface properties. Optimizing the densification procedure, which allowed the desired fraction of Ag to remain within the apatite matrix after densification, has solved a problem related to the low wettability of Ag on hydroxyapatite. The major outcome of this study is that hot-isostatic pressing enables to reinforce the interface between hydroxyapatite and silver, thus improving the structural consistency of the prepared composite. Results are supported by investigations on microscopic fracture mechanisms. It is shown, that a toughening effect arose from the microscopic crack-bridging mechanism operated by the elasto-plastic stretching of unbroken Ag ligaments along the crack wake. A Raman piezo-spectroscopic technique enabled the in situ quantitative assessment of this bridging toughening mechanism.

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References

1. Colowacki, J. and Mulliken, J.B. (1985). Demineralized Bone Implants , Clin. Plast. Sug. 12: 233-241 .

2. Hing, K.A., Best, S.M. and Bonfield, W.J. (1999). Characterization of Porous Hydroxyapatite , Mater. Sci. Mater. in Medicine, 10: 135-145 .

3. Jarcho, N., Kay, J.L., Gumaer, R.H. and Drobeck, H.P. (1977). Tissue, Cellular and Subcellular Events at Bone/Ceramic Hydroxyapatite Interface , J. Bioeng., 1: 79-85 .

4. Sobel, H.L. and Williams, W.S. (1997). A Natural Ceramic/Polymer Layered Composite , J. Am. Ceram. Soc., 80: 1706-1710 .

5. Sarikaya, M., Liu, J. and Aksay, I.A. (1995). In: Sarikaya, M. and Aksay, I.A. (eds), Biomimetics: Design and Processing of Materials, pp. 35-90, AIP Press, New York .

6. Currey J.D. (1990). Physical Characteristics Affecting the Tensile Failure Properties of Compact Bone , J. Biomech., 23: 837-842 .

7. Pezzotti, G., Asmus, S.M.F., Ferroni, L.P. and Miki, S. (2002). In situ Polymerization into Porous Ceramics: A Novel Route to Tough Biomimetic Materials , J. Mater. Sci. Mat. Med., 13: 783-787 .

(b) De With, F., Van Dijk, H. J., Hattu, N. and Prijs, K. (1981). Preparation, Microstructure and Mechanical Properties of Dense Polycrystalline Hydroxyapatite , J. Mater. Sci., 16: 1592-1598 .

9. Zhang, X., Gubbels, G.H.M., Terpstra, R.A. and Metselaar, R. (1997). Toughening of Calcium Hydroxyapatite with Silver Particles , J. Mat. Sci., 32: 235-243 .

10.

10. Wang, P.E. and Chaki, T.K. (1994). Sintering Behavior and Mechanical Properties of Hydroxyapatite and Dicalcium Phosphate , J. Mater. Sci. Mater. Med., 5: 150-158 .

11.

(b) Spadaro, J.A., Distefano, R.J. and Chase S.E. (1991). The 17th Annual Meeting of the Society for Biomaterials, In: Russell Parsons, J. (ed), Society for Biomaterials , p. 52 , Newark, Scottsdale, USA.

12.

12. Pezzotti, G. and Asmus, S.M.F. (2001). Fracture Behavior of Hydroxyapatite/Polymer Interpenetrating Network Composites Prepared by In Situ Polymerization Process , Mat. Sci. Eng. A, 316: 231-237 .

13.

13. Pezzotti, G. (1999). In Situ Study of Fracture Mechanisms in Advanced Ceramics using Fluorescence and Raman Microprobe Spectroscopy , J. Raman Spectr., 30: 867-875 .

14.

14. Nojima, T. and Nakai, O. (1993). Stable Crack Extension of an Alumina Ceramic in Three Point Bending Test , J. Soc. Mater. Sci. Jpn., 42: 412-418 .

15.

15. Nishida, T., Hanaki, Y., Nojima, T. And Pezzotti, G. (1995). Behavior in Toughened Silicon Nitride by Stable Crack Propagation in Bending , J. Am. Ceram. Soc., 78: 3113-3116 .

16.

16. Nishida, T., Hanaki, Y. and Pezzotti, G. (1995). Effect of Notch Root Radius on the Fracture Toughness of a Fine Grained Alumina , J. Am. Ceram. Soc., 77: 606-608 .

17.

17. Kanazawa, T. (1989). Inorganic Phosphate Materials, Materials Science Monographs, Part 52, Elsevier, Amsterdam .

18.

18. Hulbert, S.S.F. (1995). Charting the Future, Advance in Science and Technology , In: Vincenzini, P. (ed), Proceedings of the 8th CIMTEC, Ceramics, p. 132 , Techna, Faenza.

19.

19. Thompson, L.R. and Raj, R. (1994). In situ Stress Strain Response of Small Metal Particles Embedded in a Ceramic Matrix , Acta Metall. Mater., 42: 2477-2485 .