Densification, microstructural evolution and dielectric properties of Ba6-3x(Sm1-yNdy)8+2x Ti18O54 microwave ceramics

Sea Fue Wang, Yung Fu Hsu, Yuh Ruey Wang, Lung Teng Cheng, Ya Chi Hsu, Jinn P. Chu, Chi Yuen Huang

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Utilizing different rare-earth cations R3+ to the Ba6-3xR8+2xTi18O54 compounds is one of effective route to tailor the dielectric constant, quality factor and temperature coefficient of frequency. In this study, densification, microstructural evolution, and microwave dielectric properties of Ba6-3x(Sm1-yNdy) 8+2xTi18O54 compound, with x ranging from 0.3 to 0.7; and y from 0 to 1.00, were investigated. The ceramics with x=0.7 [Ba3.9(Sm1-yNdy) 9.4Ti18O54] has a higher densification compared with others, due to the formation of vacancy, in the perovskite-like tetragonal cavity of the tungsten bronze-type framework structure. Differential thermal analysis and density results show that the densification of Ba6-3x(SmyNd1-y) 8+2xTi18O54 ceramics during sintering is primarily resulting from the solid state sintering process. The phase homogeneity for the Ba6-3x(Sm0.5Ndo.5) 8+2xTi18O54 system is at least extended in the range of x between 0.3 and 0.7. Combining different rare-earth cations appears not alter the single phase range in tungsten bronze-type Ba6-3xR8+2xTi18 O54 ceramics. The size of the columnar-grain in the microstructure increases with increasing the Nd/Sm ratio as well as the x value. Dielectric constant changes from 91.0 to 84.2 as the x increases from 0.3 to 0.7. Variation of the Nd/Sm ratio allows one to control the τf value to the nearly 0 ppm/°C.

Original languageEnglish
Pages (from-to)1629-1635
Number of pages7
JournalJournal of the European Ceramic Society
Volume26
Issue number9
DOIs
Publication statusPublished - 2006

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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