An experimental investigation of fracture processes in glass-ceramic sealant by means of acoustic emission V.H. Rangel-Hern  andez a,b,* , Q. Fang a , C. Babelot c , R. Lohoff c , L. Blum a a Institute of Electrochemical Process Engineering (IEK-14), Forschungszentrum Ju¨ lich GmbH, Ju¨ lich, 52425, Germany b Department of Mechanical Engineering, Engineering Division, University of Guanajuato, Salamanca, Gto., C.P. 36885, Mexico c Central Institute of Engineering, Electronics and Analytics (ZEA-1), Forschungszentrum Ju¨ lich GmbH, Ju¨ lich, 52425, Germany highlights graphical abstract  AE applied to understand fracture of glass ceramic sealant in SOCs.  Tensile tests are performed at room temperature and AE signals are recorded.  Identification of fracture mecha- nisms of sealant can be achieved.  Wave mode and frequency anal- ysis is used to identify the fracture mechanisms. article info Article history: Received 27 April 2020 Received in revised form 13 June 2020 Accepted 3 July 2020 Available online 24 July 2020 Keywords: Acoustic emission (AE) Damage mechanisms Glass-ceramic Fast fourier transform (FFT) AE energy abstract One of the essential components for ensuring the long service life of solid oxide cell (SOC) stacks is the sealant used. Therefore, in this work, an experimental investigation of the glass ceramic sealant (GCS) fracture process was carried out using an Acoustic Emission (AE) based approach. A series of tensile tests at room temperature were performed and the acoustic activity emitted was recorded by two AE sensors. An AE signal analysis was then performed using two approaches: wave mode identification and frequency content anal- ysis. To understand the fracture process of the GCS, the analysis was supported with prior knowledge of the GCS microstructure and a post-test visual analysis. This demonstrated the presence of low-frequency failure mechanisms (50e400 kHz) such as debonding, fiber pull-out and matrix cracking, and high-frequency mechanisms (>400 kHz) such as fiber breakage. The results confirm the suitability of using the acoustic emission approach for monitoring failure events and show its potential application in SOC stacks monitoring. © 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. * Corresponding author. Institute of Electrochemical Process Engineering (IEK-14), Forschungszentrum Ju¨ lich GmbH, Ju¨ lich, 52425, Germany. E-mail addresses: v.rangel-hernandez@fz-juelich.de, vrangel@ugto.mx (V.H. Rangel-Hern andez). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 45 (2020) 27539 e27550 https://doi.org/10.1016/j.ijhydene.2020.07.031 0360-3199/© 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.