Abstract
The pulse thermography (PT) technique was applied to the detection of the delamination of a multi-layered coating system composed of mullite/Si onto a reaction-bonded SiC substrate. The potential evaluation was carried out in order to detect internal delamination in multi-layered material system. Moreover, the observation of the cross sections and 3D views obtained by X-ray computed tomography (CT) indicated that the delamination occurred at the interface between the top coat and the bond coat layers. The changes in the temperature distribution obtained by PT indicated the existence of a delamination area in the top coat layer of the mullite. In particular, the lower temperature region corresponded to the delamination area. The experimental results confirmed that the PT technique is effective with respect to the internal delamination of multi-layered coating system.
Highlights
IntroductionEnvironmental barrier coatings (hereafter denoted as EBCs) are key technology for surface protection of SiC fiber reinforced SiC matrix (hereafter denoted as SiC/SiC) composites from combustion atmosphere in an advanced aero gas turbine engine
Environmental barrier coatings are key technology for surface protection of SiC fiber reinforced SiC matrix composites from combustion atmosphere in an advanced aero gas turbine engine
This study focused on evaluating the potential application of the pulse thermography (PT) technique in the detection of delamination evolved in multi-layered ceramics with a high spatial resolution using a model EBC system composed of mullite/Si/reaction bonded SiC (RBSC), which is a typical model material
Summary
Environmental barrier coatings (hereafter denoted as EBCs) are key technology for surface protection of SiC fiber reinforced SiC matrix (hereafter denoted as SiC/SiC) composites from combustion atmosphere in an advanced aero gas turbine engine. Mismatch of CTE among top coat layer, bond coat layer, and substrate generates in-plane thermal tensile stress in a silicate top coat layer and it causes mud cracks in top coat layer. Degradations of EBC layer such as melting of Si and formation of cristobalite in bond coat occur [5,6,7,8,13,14,15,16] because combustion environment in aero gas turbine engine is 1300–1700 °C with 10–30 atm and the partial pressure of H2O is 1–3 atm [17], and H2O reaches Si bond coat layer through the mud cracks in top coat layer. The formation of cristobalite causes the large tensile stress with 2–3 GPa because www.springer.com/journal/40145
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
