Development of novel temperature-stable Al2O3–TiO2-based dielectric ceramics featuring superior thermal conductivity for LTCC applications

A new composition was developed using sintering to improve the dielectric properties of low-temperature co-fired alumina (LTCA) containing CuO–TiO2–Nb2O5–Ag2O. By substituting some alumina with rutile TiO2, the second-phase compound could be changed from AgNbO3 to the rutile phase. Further, low-temp...

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Bibliographic Details
Published in:Journal of the European Ceramic Society Vol. 41; no. 1; pp. 376 - 386
Main Authors: Shigeno, Koichi, Li, Moyuan, Fujimori, Hirotaka
Format: Journal Article
Language:English
Published: Elsevier Ltd 01.01.2021
Subjects:
Al2O3
Low-Temperature co-fired ceramics (LTCCs)
Microwave dielectric
Property
Thermal conductivity
TiO2
LTCA
LTCC
XRD
Low-Temperature co-fired ceramics (LTCCs)
Al2O3
EDS
Microwave dielectric
TCE
Thermal conductivity
PVA
XPS
TEM
Property
FIB
TiO2
ISSN:0955-2219, 1873-619X
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Summary:A new composition was developed using sintering to improve the dielectric properties of low-temperature co-fired alumina (LTCA) containing CuO–TiO2–Nb2O5–Ag2O. By substituting some alumina with rutile TiO2, the second-phase compound could be changed from AgNbO3 to the rutile phase. Further, low-temperature sintering at temperatures below 960 °C was possible, suppressing Al2TiO5 formation during firing. The dielectric characteristics, particularly the temperature coefficient of the resonant frequency (τf) and Q × f values, were improved without significantly reducing the sinterability and thermal conductivity. The dielectric properties of the developed 88Al2O3–12TiO2-based ceramic were εr: 14.7, τf: +0.8 ppm/K, and Q × f: 13,383 GHz (at ∼10 GHz) at a firing temperature of 940 °C. The thermal conductivity was 18.5 W/mK, which is the highest value for reported temperature-stable low-temperature co-fired ceramics (LTCCs). These results provide one of the key technologies for the practical application of LTCCs with superior thermal conductivities.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2020.08.072