97. Synthesis and Crystal Phase Evaluation of Hydroxylapatite Using the Rietveld-Maximum Entropy Method

  1. Edgar Lara-Curzio and
  2. Michael J. Readey
  1. AndrÉ Vitor Chaves de Andrade1,2,3,
  2. José Caetano Zurita da Silva1,4,
  3. Carlos Oliveira Paiva-Santos1,2,
  4. Cleverson Weber1,5,
  5. Vegner Hizau dos Santos Utuni1,2,
  6. Sérgio Mazurek Tebcherani1,4,
  7. Christiane Phihppini Ferreira Borges1,4,
  8. Elias da Costa1,5,
  9. Salvador Martinez Manent1,6 and
  10. Av. Gal Carlos Cavalcanti1,2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291191.ch97

28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4

28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4

How to Cite

de Andrade, A. V. C., da Silva, J. C. Z., Paiva-Santos, C. O., Weber, C., dos Santos Utuni, V. H., Tebcherani, S. M., Borges, C. P. F., da Costa, E., Manent, S. M. and Cavalcanti, Av. G. C. (2004) Synthesis and Crystal Phase Evaluation of Hydroxylapatite Using the Rietveld-Maximum Entropy Method, in 28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4 (eds E. Lara-Curzio and M. J. Readey), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291191.ch97

Author Information

  1. 1

    4748 Uvaranas-84030-900-Ponta Grossa-PR-Brazil

  2. 2

    Instituto de Quimica de Araraquara–UNESP–Depto. de Fisico-Quimica–LABCACC–LIEC

  3. 3

    Universidade Estadual de Ponta Grossa–Departamento de Fisica–CIPP–LIMAC

  4. 4

    Universidade Estadual de Ponta Grossa–Departamento de Quimicia–CIPP–LIMAC

  5. 5

    Universidade Estadual de Ponta Grossa–CIPP–LIMAC

  6. 6

    Universidad de Barcelona–Fac. Geologia–Depto. Crystallografia–Spain

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2004

ISBN Information

Print ISBN: 9780470051528

Online ISBN: 9780470291191

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Keywords:

  • maximum entropy;
  • polycrystalline materials;
  • electron density;
  • chemical precipitation;
  • structure refinement

Summary

Bioceramic systems based on hydroxylapatite (HAP) are an important class of bioactive materials that may promote bone regeneration. The aim of this research was to evaluate how the stoichiometry of HAP influences its microstructural properties when diagnosed using the combined Rietveld method and Maximum entropy method (MEM). The Rietveld Method (RM) is recognizably a powerful tool used to obtain structural and microstructural information of polycrystalline samples analyzed by x-ray diffraction. Latterly have combined the RM with the maximum entropy method (MEM), with the goal of improve structural refinement results. The MEM provides high resolution maps of electron density and their analysis leave the accurate localization of atoms inside of unit cell. Like that, cycles Rietveld-MEM allow an excellent structural refinement. In this work, a hydroxylapatite sample obtained by emulsion method had its structure refined using one cycle Rietveld-MEM with x-ray diffraction data. The indices obtained in initial refinement was Rwp = 7.50%, Re = 6.56%, S = 1.14% e RB = 1.03%. After MEM refinement and electron densities maps analysis to correction of atomics positions, the news indicators of Rietveld refinement quality was Rwp = 7.35%, Re = 6.56%, S = 1.12% and Rb = 0.75%. The excellent result obtained to RB shows the efficiency of MEM as auxiliary in the refinement of structure of hydroxylapatite by RM.