CMAS Corrosion Behavior and Protection Method of Thermal Barrier Coatings for Aeroengine
GUO Lei1,2,3(), GAO Yuan1, YE Fuxing1,2,3, ZHANG Xinmu1
1.School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China 2.Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072, China 3.Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
Cite this article:
GUO Lei, GAO Yuan, YE Fuxing, ZHANG Xinmu. CMAS Corrosion Behavior and Protection Method of Thermal Barrier Coatings for Aeroengine. Acta Metall Sin, 2021, 57(9): 1184-1198.
Thermal barrier coating (TBC) is a core aero-engine turbine blade technology, which can significantly increase an engine's operating temperature, thrust, and working efficiency. Moreover, high-engine operating temperatures make aero-engine turbine blades and their TBCs suffer from severe corrosion of environmental deposits (the main components are CaO, MgO, Al2O3, and SiO2, together referred to as CMAS), causing premature failure. CMAS corrosion has become a key issue that limits the service temperature and lifetimes of TBCs, and its protection has been a research hotspot. In this paper, first, the scholars' understanding of CMAS corrosion to TBCs and the characteristics of CMAS were reviewed. Then, CMAS corrosion mechanisms for TBCs were briefly described. The protection methods of TBCs from CMAS corrosion were elaborated from the aspects of TBC's surface protection layer design, coating component modification, new CMAS-resistant coating materials development, and coating microstructure design. Finally, the application of TBCs in ultrahigh temperature environments and the development direction of corrosion protection were forecasted.
Fig.1 Cross-section microstructures of yttria partially stabilized zirconia (YSZ) coatings by different preparation methods[34](a) air plasma spraying (APS) (b) electron beam physical vapor deposition (EB-PVD)
Fig.2 Degradation of thermal barrier coatings (TBCs) by CMAS (CaO, MgO, Al2O3, and SiO2) at high temperatures(a) thermochemical degradation[43](b) thermomechanical degradation[13]
Fig.3 Cross-sectional images of YSZ coatings with Pt films after heat treatment at 1250oC for 4 h with CMAS deposits[54]
Fig.4 Cross-sectional microstructures of Ti2AlC (a) and EDS results of Ca (b), Mg (c), Al (d), Ti (e), and O (f) elements[72]
Fig.5 Cross-sectional microstructures with low (a, c) and high (b, d) magnifications of LaPO4/YSZ coatings after CMAS attack at 1250oC for 2 h (a, b) and 10 h (c, d)[95]
Fig.6 Surface and fracture cross-sectional morphologies of laser-glazed coatings before (a, c, e) and after (b, d, f) parameter optimization
Fig.7 Micrographs of laser-glazed coatings after CMAS attack at 1250oC for 0.5 h (a, b) and 4 h (c, d) [43]
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