TY - JOUR
T1 - Structure and Microwave Dielectric Properties of Ca5A4TiO17 (A = Nb, Ta) Ceramics
AU - Joseph, Tony
AU - Anjana, P. S.
AU - Letourneau, S.
AU - Ubic, R.
AU - van Smaalen, Sander
AU - Sebastian, M. T.
PY - 2010/5/15
Y1 - 2010/5/15
N2 - 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.
AB - 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.
KW - Ceramics
KW - Crystal structure
KW - Dielectric properties
KW - Electron diffraction
UR - http://www.scopus.com/inward/record.url?scp=77949485004&partnerID=8YFLogxK
UR - https://scholarworks.boisestate.edu/mse_facpubs/65
U2 - 10.1016/j.matchemphys.2009.12.046
DO - 10.1016/j.matchemphys.2009.12.046
M3 - Article
SN - 0254-0584
VL - 121
SP - 77
EP - 82
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 1-2
ER -