Thermal Fracture Mechanisms in Plasma Sprayed Thermal Barrier Coatings under Cyclic Laser Irradiation

    Published: Jan 2001

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    An advanced acoustic emission (AE) system was used to monitor the degradation progression of plasma sprayed thermal barrier coatings (TBCs) subjected to cyclic infrared laser irradiation. AE signals recorded by a displacement-type sensor were utilized to determine the fracture dynamics of the coatings by a waveform simulation. The results indicated that coating damage was induced quickly during the cooling period of the cycling tests, and most AE events were classified into Mode-I fracture. Following the initiation of vertical Mode-I cracking in the coatings, delamination (Mode-I and II) occurred under the laser irradiation over 70W. The estimated source parameters revealed that the fracture and frequency depend on coating thickness, structures and heating conditions, and the thermally induced damage in the TBCs can be reduced by reducing the thickness of the ZrO2 coating and further applying the bond layer.


    Thermal barrier coating, plasma spray, laser irradiation, acoustic emission, thermal shock, fracture dynamics

    Author Information:

    Ma, X. Q.
    Research fellow and professor, Aoyama Gakuin University, Tokyo,

    Takemoto, M.
    Research fellow and professor, Aoyama Gakuin University, Tokyo,

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP42149S

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