Thermal expansion of type A carbonate apatite

Toru Tonegawa, Toshiyuki Ikoma, Yasushi Suetsugu, Naoki Igawa, Yoshitaka Matsushita, Tomohiko Yoshioka, Nobutaka Hanagata, Junzo Tanaka

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Type A carbonate apatite powder, in which carbonate ion was completely substituted for the hydroxyl site, was synthesized by heating a low crystalline and stoichiometric hydroxyapatite powder under flow of a dry carbon dioxide gas at 1000 °C for 24 h. Its chemical formula was determined to be Ca 10(PO4)6(CO3) 0.93±0.06 from compositional and infrared spectroscopic analyses. The X-ray and neutron diffraction patterns of type A carbonate apatite showed the extra diffractions attributed to monoclinic symmetry with the space group Pb. The thermal expansion property of the type A carbonate apatite was determined from neutron powder diffraction data at 25, 200, 400 and 500 °C. The extra diffractions attributed to the monoclinic symmetry were not diminished at the high temperatures. The thermal lattice expansion coefficients were, for the first time, calculated to be αa = 13.1 × 10 -6 °C-1, αb = 34.9 × 10 -6 °C-1 and αc = 8.1 × 10 -6 °C-1 by using a Le Bail refinement.

Original languageEnglish
Pages (from-to)171-175
Number of pages5
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Issue number1-3
Publication statusPublished - Mar 19 2010
Externally publishedYes


  • Neutron powder diffraction
  • Thermal expansion
  • Type A carbonate apatite
  • Whole powder fitting method

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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