An experimental investigation of fracture processes in glass-ceramic sealant by means of acoustic emission

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 analysis. 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 (50–400 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