Role of Intermediate Phase Formation in the Preparation of Ba4Y2O7∙CO2

D. A. Warner, R. E. Riman

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The objective of this study was to determine the reaction conditions that facilitate optimal formation of Ba4Y2O7∙CO22, a compound useful for the preparation of the high-temperature superconductor YBa2Cu3O7-x. Ba4Y2O7∙CO2powders were prepared by conventional, colloid, and coprecipitation powder processing methods to assess the impact of the preparation technique and consequent particle mixing on the Ba4Y2O7∙CO22 formation mechanism and kinetics. The phase assemblage and phase purity were assessed as a function of solid-state reaction temperature (950-1150 °C) and soak time (2.5-20 h). Phase-pure Ba4Y2O7∙CO2was prepared with a 20-h soak at 1050 °C. However, the powder synthesis method played no significant role in phase development. This surprising observation indicates that diffusion of the reactant species probably is not a factor in promoting formation of Ba4Y2O7∙CO2as is observed in most solid-state reactions. Instead, Ba4Y2O5∙2CO2intermediate phase formation segregates the system to the extent that the degree of homogeneity imparted by all three synthesis methods is equivalent. Formation of the Ba4Y2O5∙2CO2intermediate may be related to nucleation and growth kinetics, which can be independent of the powder characteristics or mixedness of the system.

Original languageEnglish (US)
Pages (from-to)197-204
Number of pages8
JournalChemistry of Materials
Volume4
Issue number1
DOIs
StatePublished - Feb 1 1992

All Science Journal Classification (ASJC) codes

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

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