Detail publikace

Formation of strontium-yttrium germanium anionic lacunar apatite (Sr2+δY6.67+(2δ/3)[GeO4]6O2δ) as the intermediate phase of oxygen-rich yttrium-germanium apatite (Y9.333+ε[GeO4]6O2+3/2ε)

PTÁČEK, P. OPRAVIL, T. ŠOUKAL, F. BARTONÍČKOVÁ, E. TKACZ, J.

Originální název

Formation of strontium-yttrium germanium anionic lacunar apatite (Sr2+δY6.67+(2δ/3)[GeO4]6O2δ) as the intermediate phase of oxygen-rich yttrium-germanium apatite (Y9.333+ε[GeO4]6O2+3/2ε)

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

The formation of metastable strontium-yttrium(III) (hexakis) germanium(IV) lacunar apatite (P63/m, a=11.426 Å, c=8.224 Å and Z=2) was observed during the thermal treatment of SrCO3, Y2O3, and GeO2 powder precursors using the ceramic method in an oxygen atmosphere. The utilization of an oxygen atmosphere restricts the extensive reduction of GeO2 and enables us to explain a new potential mechanism for the stabilization of lead-free lacunar apatites. This mechanism involves the use of electrons localized in a neighborhood of oxygen vacancies. Charged vacancies serve as active sites for the ionosorption of oxygen molecules and their subsequent transformation into lattice oxygen anions, which fill the vacancies at the X-site. The estimation of system thermodynamics shows that apatite undergoes a transformation to a more stable state at δ≥0.1, i.e., at the value that corresponds to the composition of prepared apatite. As the temperature and time of the thermal treatment increases, the process of incongruent melting leads to the formation of oxygen-rich yttrium-germanium apatite (YGAp, Y9.333+ε[GeO4]6O2+3/2ε) and strontium-yttrium-germanium glass. The YGAp phase is also formed during the annealing of lacunar apatite in an oxygen atmosphere.

Klíčová slova

Apatite, Yttrium-germanium apatiteLacunar apatiteOxygen-rich apatiteCeramic method

Autoři

PTÁČEK, P.; OPRAVIL, T.; ŠOUKAL, F.; BARTONÍČKOVÁ, E.; TKACZ, J.

Vydáno

31. 7. 2017

Nakladatel

Elsevier Ltd

Místo

THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND

ISSN

0272-8842

Periodikum

Ceramics International

Ročník

10

Číslo

43

Stát

Spojené království Velké Británie a Severního Irska

Strany od

7827

Strany do

7838

Strany počet

12

URL

http://www.sciencedirect.com/science/article/pii/S0272884217304686

BibTex

@article{BUT141541,
  author="Petr {Ptáček} and Tomáš {Opravil} and František {Šoukal} and Eva {Bartoníčková} and Jakub {Tkacz}",
  title="Formation of strontium-yttrium germanium anionic lacunar apatite (Sr2+δY6.67+(2δ/3)[GeO4]6O2δ) as the intermediate phase of oxygen-rich yttrium-germanium apatite (Y9.333+ε[GeO4]6O2+3/2ε)",
  journal="Ceramics International",
  year="2017",
  volume="10",
  number="43",
  pages="7827--7838",
  doi="10.1016/j.ceramint.2017.03.097",
  issn="0272-8842",
  url="http://www.sciencedirect.com/science/article/pii/S0272884217304686"
}