Abstract
The TC/BC interface morphology in APS TBC is one of the important factors leading to crack propagation and coating failure. Long cracks are found near the bulge on the TC/BC interface. In this study, the TBC model with the bulge on the interface is developed to explore the influence of the bulge on the coating failure. Dynamic TGO growth and crack propagation are considered in the model. The effects of the bulge on the stress state and crack propagation in the ceramic layer are examined. Moreover, the effects of the distribution and number of bulges are also investigated. The results show that the bulge on the interface results in the redistribution of local stress. The early cracking of the ceramic layer occurs near the top of the bulge. One bulge near the peak or valley of the interface leads to a coating life reduction of about 75% compared with that without a bulge. The increase in the number of bulges further decreases the coating life, which is independent of the bulge location. The results in this work indicate that a smooth TC/BC interface obtained by some possible surface treatments may be an optional scenario for improving coating life.
Highlights
Thermal barrier coatings (TBCs) are mainly coated on the high-temperature hot components for aero engines or gas turbines, such as combustion chambers, blades, and fuel nozzles
The typical TBC system consists of two layers: ceramic top coat (TC) and bond coat (BC)
The results indicated that the rough TC/BC interface led to huge stress in the local regions, especially when thermally grown oxide (TGO) growth was considered
Summary
Thermal barrier coatings (TBCs) are mainly coated on the high-temperature hot components for aero engines or gas turbines, such as combustion chambers, blades, and fuel nozzles. Established a TBC model based on the real interface morphology and analyzed the effect of TGO growth on the stress state at the interface. Weeks et al [49] thought that the ratio of amplitude to wavelength can be optimized to delay the ceramic cracking and coating spallation They experimentally optimized the roughness of the TC/BC interface and found that the interface morphology with 15.0 μm ± 3.0 μm roughness, 66◦ ± 3◦ slope, and 120.0 μm ± 10.0 μm spacing could improve the TBC lifetime. Early ceramic layer cracking can be found near the bulge of the interface [51] In a word, these local bulges may contribute to the coating failure. In order to develop advanced TBC with long life, it is urgent to understand the effects of the local bulge on the stress state and ceramic cracking. The influences of the location and number of the bulge on the crack evolution and coating failure were investigated
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.
