The structure of microwave dielectric properties of ceramics based on Ba{sub 3.75}Nd{sub 9.5}Ti{sub 18}O{sub 54}

Conference · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:86571

Azough, F; Setasuwon, P; Freer, R ^[1]

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1. Univ. of Manchester (United Kingdom)

Ceramics of Ba{sub 3.75-x}Bi{sub x}Nd{sub 9.5}Ti{sub 18}O{sub 54+y} with O{le}x{le}0.45 ({open_quotes}Bi-substituted{close_quotes}) and Ba{sub 3.75}Nd{sub 9.5}Ti{sub 18}O{sub 54} plus 1.0-5.0 wt% Bi{sub 2}O{sub 3} ({open_quotes}Bi-added{close_quotes}) were prepared by the mixed oxide route. Sintering at temperatures of 1350-1500{degrees}C yielded products with densities up to 5.6 gm cm{sup -3}. TEM electron diffraction studies of Bi-frees samples confirmed the space group to be Pnam; the cell parameter in the c-direction was doubled. High resolution X-ray diffraction studies enabled the structure to be refined and site occupancies identified; three primary cation sites were disordered in Ba/Nd. Microwave dielectric properties at 3GHz showed that {open_quotes}substitution{close_quotes}of Bi(O{le}x{le}0.35) yielded er values of 80, increased TCC from -80 (x=0) to -40 ppm/{degrees}C when x=0.35, but decreased Q from 2400 (x=0) to {approximately} 2000 (for x > 0.15).

• OSTI ID: 86571
• Report Number(s): CONF-941199--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
DIELECTRIC PROPERTIES
LATTICE PARAMETERS
MICROSTRUCTURE
NEODYMIUM COMPOUNDS
PERMITTIVITY
SINTERING
TITANATES
X-RAY DIFFRACTION