Research on Chemical Intermediates

, Volume 25, Issue 2, pp 229–242 | Cite as

Perovskite related phases in the Sr5Nb4O15 - SrTiO3 - Sr4Nb2O9 system

  • D. Pasero
  • R. J. D. Tilley
Article

Abstract

Phase relations have been investigated within the Sr5Nb4O15−SrTiO3−Sr4Nb2O9 region of the SrO−Nb2O5−TiO2 system with a view to clarifying the occurrence of fully oxidised perovskite related phases. Overall phase analysis was carried out by powder X-ray diffraction and microstructures were clarified by transmission electron microscopy. There is only one main composition triangle in this area at 1350°C. The tie-line between Sr5Nb4O15 and SrTiO3 contains a homologous series of hexagonal layered perovskite phases including Sr6Nb4TiO18 and Sr7Nb4Ti2O21. The phase Sr4Nb2O9 is a nonstoichiometric phase with a disordered perovskite structure. There is some extension of this phase along the Sr4Nb2O9−SrTiO3 tie-line, but SrTiO3 does not show a significant composition range. Samples with a composition Sr4Nb2O9, when heated at 900°C show several ordered modifications. Samples along the Sr4Nb2O9−SrTiO3 tie-line which are annealed at 900°C contain these ordered materials together with samples showing considerable short range order which increases as the Ti content increases.

Keywords

Perovskite Diffuse Scattering Image Simulation Solid Solution Phase Phase Line 

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Copyright information

© Springer 1999

Authors and Affiliations

  • D. Pasero
    • 1
  • R. J. D. Tilley
    • 1
  1. 1.School of EngineeringUniversity of CardiffCardiffUK

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