Thermal and mechanical properties of Ta2O5 doped La2Ce2O7 thermal barrier coatings prepared by atmospheric plasma spraying

La2Ce2O7 (LC) is a new promising thermal barrier coating (TBC) material for high-temperature applications. However, the sudden decrease of thermal expansion coefficient (TEC) at ∼623 K limits its application. In this study, the plasma-sprayed La2Ce1.7Ta0.3O7.15 (LCT) coating was developed by partial...

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Bibliographic Details
Published in:Journal of the European Ceramic Society Vol. 39; no. 7; pp. 2379 - 2388
Main Authors: Zhang, Hao, Sun, Junbin, Duo, Shuwang, Zhou, Xin, Yuan, Jieyan, Dong, Shujuan, Yang, Xiong, Zeng, Jinyan, Jiang, Jianing, Deng, Longhui, Cao, Xueqiang
Format: Journal Article
Language:English
Published: Elsevier Ltd 01.07.2019
Subjects:
Failure mechanism
La2Ce2O7
Ta2O5 doping
Thermal conductivity
Failure mechanism
Ta2O5 doping
Thermal conductivity
La2Ce2O7
ISSN:0955-2219, 1873-619X
Online Access:Get full text
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Summary:La2Ce2O7 (LC) is a new promising thermal barrier coating (TBC) material for high-temperature applications. However, the sudden decrease of thermal expansion coefficient (TEC) at ∼623 K limits its application. In this study, the plasma-sprayed La2Ce1.7Ta0.3O7.15 (LCT) coating was developed by partial substitution of Ce4+ in LC with Ta5+. LCT coating shows lower thermal conductivity between 298 K and 1273 K (0.54–0.71 W/(m·K)) than LC coating (0.65–0.85 W/(m·K)) and the traditional yttria partially stabilized zirconia (YSZ) coating (1.53–1.72 W/(m·K)). It also exhibits excellent thermal stability at least up to 1573 K for 1000 h. What is more, the sudden TEC drop is suppressed owing to the reduced oxygen vacancy concentration governed by Ta5+-substitution content. As a result, LCT TBC shows an improved thermal cycling lifetime in an air furnace as compared to LC TBC.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2019.02.041