Investigation of failure mechanism of thermal barrier coatings (TBCs) deposited by EB-PVD technique

6th Vacuum and Surface Sciences Conference of Asia and Australia

Shahid, M.R.^1 ; Abbas, Musharaf^2

National University of Science and Technology, H-12, Islamabad 44000, Pakistan^1

Beijing University of Aeronautics and Astronautics, No. 37 Xueyuan Road, Beijing 100191, China^2

关键词: Bond coats;    Ceramic coats;    Electron beam-physical vapor deposition;    Failure mechanism;    Metallic bonds;    Ni-based superalloys;    Non-uniform;    Thermal barrier coating (TBCs);   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/439/1/012021/pdf
DOI  :  10.1088/1742-6596/439/1/012021

来源: IOP

【 摘 要 】

Failure mechanism of thermal barrier coatings (TBCs) prepared by electron beam physical vapor deposition (EB-PVD) technique owing to formation of micro cracks was investigated. The TBCs were deposited on the Ni-based super alloy IN-100 and the micro cracks were observed within the top ceramic coat of thermally cycled TBCs at 1050°C. It was observed that these cracks propagate in the ceramic coat in the direction normal to interface while no cracks were observed in the bond coat. SEM/EDS studies revealed that some non-uniform oxides were formed on the interface between ceramic top and metallic bond coat just below the cracks. Study proposed that the cracks were initiated due to stress owing to big difference in Pilling-Bed worth ratio of non-uniform oxides as well as thermal stress, which caused the formation of cracks in top ceramic coat leading to failure of TBCs