Abstract No.:
5289

 Scheduled at:
Friday, June 09, 2017, Hall 12 1:40 PM
Aviation & Power Generation Industry VI


 Title:
Effect of the microstructural design of plasma-sprayed thermal barrier coatings on its the thermal cycling behavior

 Authors:
Chang-Jiu Li* / Xi'an Jiaotong University, P.R. China
Tao Liu / Xi'an Jiaotong University, China
Shu-Wei Yao/ Xi'an Jiaotong University,
Chang-Jiu Li/ Xi'an Jiaotong University,
Guan-Jun Yang/ Xi'an Jiaotong University,

 Abstract:
The microstructure and properties of the ceramic layer in TBCs has important influence on the thermal cycling behavior of plasma-sprayed thermal barrier coatings (TBCs). In this study, the microstructure of 8YSZ ceramic layer was adjusted by using graphite as pore former. 8YSZ ceramic coatings with different high porosities and pore structure were prepared by removing graphite in the coatings of different graphite contents at 800oC in air. A double layer TBC with higher porosity of top YSZ layer was designed to enhance the durability of TBCs. The thermal cycling behavior of conventional TBCs with single 8YSZ layer and the TBCs with two 8YSZ layers, were characterized under isothermal cycling conditions. Compared with the thermal cycling life of conventional TBCs of single 8YSZ layer, the thermal cycling life time of the double-layered TBCs increases by about 40% when the porosity of the top ceramic layer increased to about 23%. However, when the porosity of the top ceramic layer further increases to about 30%, the failure mode changed from spalling of the YSZ by cracking near TGO to cracking within the top ceramic layer which leads to significant decrease of thermal cycling lifetime. An elastic-energy model is proposed to explain the failure modes of double-layered TBCs and design the TBCs with higher thermal cycling performancve.

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