Structural, Vibrational and Mechanical Studies of Hydroxyapatite   produced by wet-chemical methods
  Hydroxyapatite samples were produced by two different wet-chemical methods, and characterized by x-ray diffraction, infrared and compression strength measurements. The x-ray diffraction measurements were simulated using the Rietveld method, and structural data as lattice parameters and average crystallite size were obtained. The infrared spectra showed the presence of CO$_3^{2-}$ ions in all samples, indicating a contamination by these ions. By mixing samples produced by both methods, a bioceramic was obtained and, after sintering, samples with very high compression strengths (26--30 MPa) were obtained. 
K. Donadel, M. C. M. Laranjeira, V. L. Gon\c{c}alves, V. T. F\'avere,   K. D. Machado, J. C. de Lima, L. H. M. Prates