Well-aligned polycrystalline lanthanum silicate oxyapatite grown by reactive diffusion between solid La{sub 2}SiO{sub 5} and gases [SiO+1/2O{sub 2}]

Journal Article · Tue Mar 15 00:00:00 EDT 2016 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2015.12.007· OSTI ID:22577779

Fukuda, Koichiro ^[1]; Hasegawa, Ryo; Kitagawa, Takuya; Nakamori, Hiroshi; Asaka, Toru ^[1]; Berghout, Abid; Béchade, Emilie; Masson, Olivier; Jouin, Jenny; Thomas, Philippe ^[2]

---

1. Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)
2. Science des Procédés Céramiques et de Traitements de Surface (SPCTS), UMR 7315 CNRS, Université de Limoges, Centre Européen de la Céramique, 12 Rue Atlantis, 87068 Limoges Cedex (France)

The c-axis-oriented polycrystalline lanthanum silicate oxyapatite, La{sub 9.48}(Si{sub 5.89}□{sub 0.11})O{sub 26} (□ denotes a vacancy in the Si site), was successfully prepared by the reactive diffusion between randomly grain-oriented La{sub 2}SiO{sub 5} polycrystal and [SiO+1/2O{sub 2}] gases at 1873 K in Ar atmosphere. The polycrystal was characterized using optical microscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, micro-Raman spectroscopy, X-ray diffractometry, and impedance spectroscopy. The crystal structure (space group P6{sub 3}/m) showed the deficiency of Si site at ca. 1.9%. The bulk oxide-ion conductivity along the grain-alignment direction steadily increased from 9.2 × 10{sup −3} to 1.17 × 10{sup −2} S/cm with increasing temperature from 923 to 1073 K. The activation energy of conduction was 0.23(2) eV. - Graphical abstract: We have successfully prepared the highly c-axis-oriented polycrystalline La{sub 9.48}(Si{sub 5.89}□{sub 0.11})O{sub 26} by the reactive diffusion between randomly grain-oriented La{sub 2}SiO{sub 5} polycrystal and [SiO + 1/2O{sub 2}] gases at 1873 K in Ar atmosphere. The crystal structure (space group P6{sub 3}/m) showed the deficiency of Si site of ca. 1.9%. - Highlights: • The c-axis-oriented polycrystalline La{sub 9.48}(Si{sub 5.89}□{sub 0.11})O{sub 26} is successfully prepared. • Crystal structure of La{sub 9.48}(Si{sub 5.89}□{sub 0.11})O{sub 26} is determined by single-crystal XRD. • The polycrystal shows relatively high oxide ion conductivity along the common c-axis. • Reactive diffusion is successfully used for the preparation of grain-aligned ceramics.

• OSTI ID: 22577779
• Journal Information: Journal of Solid State Chemistry, Vol. 235; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
APATITES
CERAMICS
DIFFUSION
ELECTRON SCANNING
HEXAGONAL LATTICES
IONIC CONDUCTIVITY
IONS
LANTHANUM
LANTHANUM SILICATES
MONOCRYSTALS
OPTICAL MICROSCOPY
POLYCRYSTALS
RAMAN SPECTROSCOPY
SCANNING ELECTRON MICROSCOPY
SILICON OXIDES
SOLIDS
SPACE GROUPS
X RADIATION
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY