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Double-ceramic-layer thermal barrier coatings based on La2(Zr0.7Ce0.3)2O7/La2Ce2O7 deposited by electron beam-physical vapor deposition |
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| Authors: | ZH Xu LM He RD Mu GH Huang |
| Institution: | a Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095, China b State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China c Graduate School of Chinese Academy of Sciences, Beijing 100039, China |
| Abstract: | Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La2(Zr0.7Ce0.3)2O7 (LZ7C3) and La2Ce2O7 (LC) were deposited by electron beam-physical vapor deposition (EB-PVD). The composition, interdiffusion, surface and cross-sectional morphologies, cyclic oxidation behavior of DCL coating were studied. Energy dispersive spectroscopy and X-ray diffraction analyses indicate that both LZ7C3 and LC coatings are effectively fabricated by a single LZ7C3 ingot with properly controlling the deposition energy. The chemical compatibility of LC coating and thermally grown oxide (TGO) layer is unstable. LaAlO3 is formed due to the chemical reaction between LC and Al2O3 which is the main composition of TGO layer. Additionally, the thermal cycling behavior of DCL coating is influenced by the interdiffusion of Zr and Ce between LZ7C3 and LC coatings. The failure of DCL coating is a result of the sintering of LZ7C3 coating surface, the chemical incompatibility of LC coating and TGO layer and the abnormal oxidation of bond coat. Since no single material that has been studied so far satisfies all the requirements for high temperature applications, DCL coating is an important development direction of TBCs. |
| Keywords: | Thermal barrier coatings EB-PVD Double-ceramic-layer La2(Zr0 7Ce0 3)2O7 La2Ce2O7 Thermal cycling |
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