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Nonlinear property of SrCoO3-doped ZnO ceramics sintered in a reducing atmosphere and multilayer ceramic varistors with base metal electrodes

Published online by Cambridge University Press:  13 August 2015

Yoshiko Higashi ,
Masayuki Hogiri  and
Eiichi Koga
Yoshiko Higashi*
Affiliation:
Corporate Engineering Division, Automotive & Industrial Systems Company, Panasonic Co., Ltd., 1006 Kadoma, Kadoma City, Osaka 571-8506, Japan
Masayuki Hogiri
Affiliation:
Corporate Engineering Division, Automotive & Industrial Systems Company, Panasonic Co., Ltd., 1006 Kadoma, Kadoma City, Osaka 571-8506, Japan
Eiichi Koga
Affiliation:
Circuit Components Business Unit, Automotive & Industrial Systems Company, Panasonic Co., Ltd., 1037-2 Kamiosatsu, Chitose City, Hokkaido 066-8502, Japan
*
a)Address all correspondence to this author. e-mail: higashi.yoshiko@jp.panasonic.com
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Abstract

This study describes the nonlinear characteristics of SrCoO3-doped ZnO varistors and multilayer ceramic varistors (MLCVs) with copper electrodes, both of which are sintered in a reducing atmosphere. Due to postannealing effects in air or N2 with low-oxygen concentration (0.02%), bulk disks can be sintered in a reducing atmosphere, with a usable V1 mA/mm (e.g., 1600 V for bulk bodies or 1200 V for Cu cofiring) and highly nonlinear indices (α10 μA = V1 mA/V10 μA < 1.3), regardless of whether cofiring with Cu electrodes on disk surfaces was conducted or not. On the basis of this procedure, Cu-MLCVs were successfully produced, without oxidation of Cu-internal electrodes or structural defects. They exhibited high stability as well as a useful nonlinearity of V1 mA = 10.4 V and α10 μA = 1.93. The resultant stability against electrostatic discharge (ESD) satisfies the highest standard of level 4 in IEC61000-4-2 (ESD stability test). This is the first report to show that MLCVs with base metals have practical properties, including stability.

Keywords

grain boundariesZnannealing
Type
Articles
Information
Journal of Materials Research , Volume 30 , Issue 15 , 14 August 2015 , pp. 2300 - 2309
Copyright
Copyright © Materials Research Society 2015 

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References

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