Structure and Microwave Dielectric Properties of Ca5A4TiO17 (A = Nb, Ta) Ceramics

Tony Joseph, P. S. Anjana, S. Letourneau, R. Ubic, Sander van Smaalen, M. T. Sebastian

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Ca 5 A 4 TiO 17 (A = Nb, Ta) dielectric ceramics were prepared by the conventional solid-state ceramic route. The structure and microstructure of the ceramics were investigated by X-ray diffraction, transmission electron microscopy and scanning electron microscopic techniques. The electron diffraction patterns of Ca 5 A 4 TiO 17 were indexed according to the model in P2 1 / c . The microwave dielectric properties of the sintered ceramics were measured in the frequency range of 3–6 GHz. Ca 5 Nb 4 TiO 17 ceramics had a relative permittivity, ε r = 44.9 (porosity corrected value 49.4), quality factor, Q u × f = 17,600 GHz (at 4.13 GHz) and temperature coefficient of resonant frequency, τ f = −112.9 ppm °C −1 , whereas for Ca 5 Ta 4 TiO 17 , the obtained values were 40.1 (porosity corrected value 44.1), 16,450 GHz (at 4.22 GHz) and −53.6 ppm °C −1 , respectively. The density of Ca 5 A 4 TiO 17 ceramics was increased by adding small amounts of zinc borosilicate (60ZnO–30B 2 O 3 –10SiO 2 ) glass. The effect of glass addition on the microwave dielectric properties of Ca 5 A 4 TiO 17 ceramics was also investigated.

Original languageAmerican English
Pages (from-to)77-82
Number of pages6
JournalMaterials Chemistry and Physics
Volume121
Issue number1-2
DOIs
StatePublished - 15 May 2010

Keywords

  • Ceramics
  • Crystal structure
  • Dielectric properties
  • Electron diffraction

EGS Disciplines

  • Materials Science and Engineering

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