Novel reaction mechanism for the synthesis of Ba2Ti 9O20 materials prepared from nano-sized oxides

Li Wen Chu, Ging Ho Hsiue, I. Nan Lin, Yi-Chun Chen

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3 Citations (Scopus)

Abstract

In this work, the phase evolution during calcinations of a BaTiO 3 and TiO2 mixture was investigated. Based on the observations, a model for the reaction sequence of the phases was proposed and a modified process was suggested, namely to synthesize Ba2Ti 9O20 materials utilizing a BaTi4O9 and BaTi5O11 mixture, instead of a BaTiO3 and TiO2 mixture, as starting materials. The phase transformation kinetics is thus greatly enhanced by this process. While the reaction of the 2BaTiO3+7TiO2 mixture requires 1100 °C/4 h to transform completely into the Ba2Ti9O20 Hollandite-like phase, it needs only 1000 °C/4 h to fulfil the phase transformation process in the BaTi5O11+BaTi 4O9 mixture. The BaTi5O11+BaTi 4O9 mixture also leads to higher sinterability and more uniform granular structure, as compared to the 2BaTiO3+7TiO 2 mixture, when these powder mixtures were densified by a direct sintering process. Furthermore, local microwave dielectric properties measured by an evanescent microwave probe (EMP) reveals that the grains of Ba 2Ti9O20 materials prepared from the BaTi 5O11+BaTi4O9 mixture possess larger dielectric constant than 2BaTiO3+7TiO2 derived ones, indicating that the BaTi5O11+BaTi4O 9 mixture has higher reactivity for the formation of the Ba 2Ti9O20 Hollandite-like phase.

Original languageEnglish
Pages (from-to)185-191
Number of pages7
JournalNanotechnology
Volume17
Issue number1
DOIs
Publication statusPublished - 2006 Jan 14

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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