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Mechanism of nanostructured fluorapatite formation from CaO, CaF2 and P2O5 precursors by mechanochemical synthesis

Nikonam Mofrad,, R ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.3184/146867818X15233705894419
  3. Publisher: Science Reviews 2000 Ltd , 2018
  4. Abstract:
  5. We determined the mechanism of mechanochemical synthesis of fluorapatite from CaO, CaF2 and P2O5 by characterisation of the intermediate compounds. We used atomic absorption spectroscopy, X-ray diffraction, field emission scanning electron microscopy, FTIR spectroscopy and transmission electron microscopy to find the transitional compounds. Investigation of the binary and ternary powder mixtures revealed the appearance of H3PO4, Ca(OH)2, Ca2P2O7 and CaCO3 as the intermediate compounds. At early stages of the milling, conversions of P2O5 to H3PO4 and CaO to Ca(OH)2 occurred in the wet atmosphere. Later, a combination of Ca(OH)2 and H3PO4 formed Ca2P2O7 while the unreacted CaO was converted to CaCO3 by CO2 of the ambient atmosphere. Spherical crystalline Ca10(PO4)6F2 particles formed after 48 hours of milling due to the reaction between Ca2P2O7, CaCO3 and CaF2. © Science Reviews 2000 Ltd. All rights reserved
  6. Keywords:
  7. Intermediate compounds ; Mechanochemical process ; Nanostructured fluorapatite ; Reaction mechanism ; Absorption spectroscopy ; Binary mixtures ; Calcite ; Calcium carbonate ; Calcium fluoride ; Field emission microscopes ; Fluorspar ; Fourier transform infrared spectroscopy ; High resolution transmission electron microscopy ; Hydrated lime ; Milling (machining) ; Scanning electron microscopy ; Transmission electron microscopy ; Ambient atmosphere ; Field emission scanning electron microscopy ; Fluorapatites ; Intermediate compound ; Mechanochemical process ; Mechanochemical synthesis ; Reaction mechanism ; Spherical crystalline ; Reaction intermediates
  8. Source: Progress in Reaction Kinetics and Mechanism ; Volume 43, Issue 3-4 , 2018 , Pages 201-210 ; 14686783 (ISSN)
  9. URL: https://journals.sagepub.com/doi/abs/10.3184/146867818X15233705894419