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Mechanical properties of reactive air brazed ceramic-metal joints for SOFC

 
: Poenicke, Andreas; Arnold, Sébastien; Schilm, Jochen; Kusnezoff, Mihails; Michaelis, Alexander

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Fulltext urn:nbn:de:0011-n-2033525 (1.4 MByte PDF)
MD5 Fingerprint: 4c8130447c86d10dc997d6176e10574a
Copyright 2012 ASM International. This paper was in proceedings of the 5th International Brazing and Soldering Conference IBSC and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.
Created on: 26.5.2012

presentation urn:nbn:de:0011-n-203352-17 (1.5 MByte PDF)
MD5 Fingerprint: 16804b170e14b0b62a0f0682c096ba02
Created on: 26.5.2012


American Welding Society, Miami/Fla.; ASM International:
IBSC 2012, 5th International Brazing and Soldering Conference. Proceedings : April 22-25, 2012, Red Rock Casino Resort Spa, Las Vegas, NV, USA
Las Vegas/Nev., 2012
ISBN: 978-1-61503-975-3
pp.450-457
International Brazing and Soldering Conference (IBSC) <5, 2012, Las Vegas/Nev.>
English
Conference Paper, Electronic Publication
Fraunhofer IKTS ()
reactive air brazing; Löten von Keramik und Metall; Fügen von SOFC

Abstract
The mechanical integrity of sealants in solid oxide fuel cells (SOFC) and their long-term stability under operating conditions are a basic requirement for a reliable operation of SOFC stacks. In this respect the use of metallic brazes is considered to have advantages in comparison to the widely used brittle glasses or glass ceramics. In this study the mechanical properties and the long-term stability of ceramic-metal joints prepared by induction heating are investigated. Fracture experiments are carried out to characterize the bending strength and failure mechanisms of silver-based reactive air brazes. Due to thinner interfacial layers the induction brazed 4-point bending specimens showed higher strength than samples brazed in conventional furnaces. Characterization of fracture surfaces wi th SEM reveals details of fracture origin and crack propagation. The cracks in the interfacial layers between braze/ceramic and braze/metal are identified as failure reason for tested samples. It is shown that during annealing in air at 850°C the 4-point bending strength decreases with time while the thickness of the oxide reaction layers increases. Failure mechanisms and possibilities for improvements of the reactive air brazing technology are discussed.

: http://publica.fraunhofer.de/documents/N-203352.html