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Microwave Dielectric Properties of CaTiO 3 ‐CaAl 1/2 Nb 1/2 O 3 Ceramics Doped with Li 3 NbO 4
Author(s) -
Kucheiko Sergey,
Yeo DongHun,
Choi JiWon,
Yoon SeokJin,
Kim HyunJai
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00272.x
Subject(s) - materials science , natural bond orbital , sintering , dielectric , ceramic , perovskite (structure) , temperature coefficient , doping , analytical chemistry (journal) , mineralogy , permittivity , crystallography , composite material , chemistry , optoelectronics , chromatography , density functional theory , computational chemistry
The microwave dielectric properties of CaTi 1− x (Al 1/2 Nb 1/2 ) x O 3 solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO 3 . The substitution of Ti 4+ by Al 3+ /Nb 5+ improved the quality factor Q of the sintered specimens. A small addition of Li 3 NbO 4 (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛ r ) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τ f ) of −2 ppm/K. Li 3 NbO 4 as a sintering additive had no harmful influence on τ f of ceramics.