Abstract No.:
5504

 Scheduled at:
Thursday, June 08, 2017, Hall 12 11:00 AM
Aviation & Power Generation Industry II


 Title:
Thermal conductivity and interfacial thermal resistance of thermal barrier coatings

 Authors:
Satoru Takahashi* / Tokyo Metropolitan University, Japan
Megumi Akoshima/ National Institute of Advanced Industrial Science and Technology, Japan
Akihiro Kanno/ TOCALO Co. Ltd., Japan
Tatsuo Suidzu/ TOCALO Co. Ltd., Japan

 Abstract:
Thermal barrier coatings (TBCs) are the indispensable technology for hot-section components of an advanced industrial gas turbine. A thermal barrier effect of a TBC depends strongly on a thermal conductivity of a ceramic top-coat (TC). Therefore, thermal conductivities of free-standing TC specimens have been reported by many researchers. But, since a TBC consists of a metallic bond-coat (BC) and a TC on a superalloy, the interfaces between the TC and the BC, and the BC and the substrate exist. It is necessary to understanding the interfacial thermal resistance between the layers as well as thermophysical properties of each layer. Baba proposed the analytical method determining the thermal diffusivity and the boundary thermal resistance in the multilayered film. This method uses an areal heat diffusion time of a multilayered specimen obtained by a laser flash technique. In the present study, the thermal conductivity of the TC, and the interfacial thermal resistance between the TC and the BC were evaluated experimentally by applying this method. Several kinds of TBC specimens with the substrate were produced by a plasma spraying. The areal heat diffusion time was measured in air at room temperature using the laser flash method. The substrate of the TBC specimen was polished stepwise mechanically, the areal heat diffusion time of the specimen was measured repeatedly with changing the total thickness of the TBC specimen. It was found that the thermal conductivity of the TC, and the interfacial thermal resistance between the TC and the BC could be obtained based on the change of the areal heat diffusion time.


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