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Journal of Ceramic Science and Technology

The Journal of Ceramic Science and Technology publishes original scientific articles on all topics of ceramic science and technology from all ceramic branches. The focus is on the scientific exploration of  the relationships between processing, microstructure and properties of sintered ceramic materials as well as on new processing routes for innovative ceramic materials. The papers may have either theoretical or experimental background. A high quality of publications will be guaranteed by a thorough double blind peer review process.

The Journal is published by Göller Verlag GmbH on behalf of the Deutsche Keramische Gesellschaft (DKG). Edited by Yu-Ping Zeng, Shanghai Institute of Ceramics, Chinese Academy of Sciences, China.

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Contacting Methods for C12A7 Electride Ceramic

K. Waetzig1, A. Rost1, J. Schilm1, M. Tajmar2, A. Michaelis1

1 Fraunhofer IKTS, Institute for Ceramic Technology and Systems, Winterbergstrasse 28, D-01277 Dresden, Germany
2 Institute of Aerospace Engineering, Technische Universität Dresden, D-01307 Dresden, Germany

received June 13, 2019, received in revised form September 5, 2019, accepted October 18, 2019

Vol. 11, No. 1, Pages 11-16   DOI: 10.4416/JCST2019-00032

Abstract

C12A7:e- ([Ca24Al28O64]4+4e-) ceramic is a material with high electrical conductivity and low work function, so that this ceramic is suitable as an electron-emitting material. Although the bulk material indicates these extraordinary properties, the surface of the ceramic is insulating. Therefore, a metallization film is needed to realize an electrical contact with low ohmic losses for the application of the material. In this study, we investigated three different metal pastes (Pt, Au and Cusil-ABA®) for contacting the surface and measured the reduction of the resistance during the firing process of the pastes. The resistance of the contacted C12A7:e- was determined as a function of the temperature under nitrogen atmosphere. Additionally, the oxidation behaviour of the electride was observed based on increasing resistance when the material was heated in air.

The lowest resistance was measured with Ag-based braze (Cusil-ABA®), however, cracking of the contacted ceramic was observed. Alternatively, contacting with Au reached a specific resistance of 5.4 Ω cm (T = 800 °C).

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Keywords

Electron emitter, conductive ceramic, C12A7, calcium aluminate, metallization, contacting

References

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