Influence of SiO2 Addition on the Dielectric Properties and Microstructure of (Ba0.96Ca0.04)(Ti0.85Zr0.15)O3 Ceramics

Volume 6 Issue 6, Pages 692 – 701

Ying-Chieh Lee, Chia-Wei Lin, Wei-Hua Lu, Wen-Jauh Chen, Wen-Hsi Lee
Published
Online: Apr 17 2009 8:10PM

DOI: 10.1111/j.1744-7402.2009.02379.x

ABSTRACT
In this study, the effect of SiO₂ doping on the
sintering behavior, microstructure, and dielectric properties of BaTiO₃-based
ceramics was investigated. Silica was added to (Ba_0.96Ca_0.04)(Ti_0.85Zr_0.15)O₃
(BCTZ) powder prepared using the solid-state method. SiO₂-doped
BCTZ ceramics with a high density and a uniform grain size were
obtained and sintered at 1220°C in a reducing atmosphere. A second phase
(BaTiSiO₅) existed in samples when SiO₂
was added in excess of 1%. The amount of the second phases was observed
to increase as the number of SiO₂ additives
increased. It was found that BCTZ ceramics sintered with SiO₂
are helpful in reducing the sintering temperature for a typical thick
film and MLCC applications. However, there were disadvantageous effects
on the dielectric properties with mere addition of SiO₂
addition (3% and 5%) due to higher formation of BaTiSiO₅.
Doping with a small amount of silica can improve the sintering and
dielectric properties of BCTZ ceramics. In addition, to understand the
effect of the BaTiSiO₅ phase on the dielectric
properties of BCTZ ceramics, the BaTiSiO₅
composition was synthesized from individual BaCO₃,
TiO₂, and SiO₂ powders
using conventional solid-state methods. X-ray diffraction results show
the presence of mainly the crystalline phase, BaTiSiO₅,
in the sintered ceramics.

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