title: Thorough analysis of silicon substitution in biphasic calcium phosphate bioceramics: a multi-technique study.
abstract: Four samples of composition Ca(10)(PO(4))(6-x)(SiO(4))(x)(OH)(2-x), with x=0.0, 0.1, 0.2 and 0.5, were prepared and characterized using powder X-ray and neutron powder diffraction, and (1)H, (31)P and (29)Si nuclear magnetic resonance (NMR) spectroscopy. The composition of the Si-substituted HAp phases was determined by joint Rietveld refinements from powder X-ray and powder neutron diffraction data. Taking into account electroneutrality, a chemical formula for the Si-substituted HAp phases with indication of the incorporated silicate amount is proposed. Solid-state (29)Si NMR confirms the presence of only Q(0) species, in good agreement with the presence of substituted HAp and beta-TCP phases only. Thanks to NMR spectroscopy, two types of protons in the Si-substituted HAp phase were identified, the new site corresponding to species engaged in hydrogen bonding with silicate anions. This allowed further refinement of the formulae for these phases with very good quantitative agreement for populations derived from the refinement and integration of NMR data.
authors.affiliation: Clermont Université, ENSCCF, Laboratoire des Matériaux Inorganiques, BP 10448, F-63000, Clermont-Ferrand, France.
authors.forename: S
authors.initials: S
authors.lastname: Gomes
authors.forename: G
authors.initials: G
authors.lastname: Renaudin
authors.forename: A
authors.initials: A
authors.lastname: Mesbah
authors.forename: E
authors.initials: E
authors.lastname: Jallot
authors.forename: C
authors.initials: C
authors.lastname: Bonhomme
authors.forename: F
authors.initials: F
authors.lastname: Babonneau
authors.forename: J-M
authors.initials: JM
authors.lastname: Nedelec
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing / Q000379:methods*; D044367:Phase Transition; D011208:Powders; D012825:Silicon / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D011208:Powders; D012825:Silicon