Experimental and numerical investigation on the thermal and mechanical behaviours of thermal barrier coatings exposed to CMAS corrosion

Journal of Advanced Ceramics

Renheng Gao¹  Fan Sun²  Xueling Fan²  Peng Jiang²  Dongxu Li²  Xiaochao Jin² 

[1] AEEC Sichuan Gas Turbine Establishment, 610500, Chengdu, China;State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi’an Jiaotong University, 710049, Xi’an, China;

关键词: thermal barrier coating (TBC);    calcium-magnesium-alumino-silicate (CMAS) corrosion;    corrosion model;    temperature field;    stress field;   

DOI  :  10.1007/s40145-021-0457-2

来源: Springer

【 摘 要 】

Calcium-magnesium-alumino-silicate (CMAS) corrosion is a critical factor which causes the failure of thermal barrier coating (TBC). CMAS attack significantly alters the temperature and stress fields in TBC, resulting in their delamination or spallation. In this work, the evolution process of TBC prepared by suspension plasma spraying (SPS) under CMAS attack is investigated. The CMAS corrosion leads to the formation of the reaction layer and subsequent bending of TBC. Based on the observations, a corrosion model is proposed to describe the generation and evolution of the reaction layer and bending of TBC. Then, numerical simulations are performed to investigate the corrosion process of free-standing TBC and the complete TBC system under CMAS attack. The corrosion model constructs a bridge for connecting two numerical models. The results show that the CMAS corrosion has a significant influence on the stress field, such as the peak stress, whereas it has little influence on the steady-state temperature field. The peak of stress increases with holding time, which increases the risk of the rupture of TBC. The Mises stress increases nonlinearly along the thick direction of the reaction layer. Furthermore, in the traditional failure zone, such as the interface of the top coat and bond coat, the stress obviously changes during CMAS corrosion.

【 授权许可】

CC BY