Research Status on Thermal Barrier Coating of Aircraft Engine Turbine Blade

With the continuous development of the aviation industry, people are putting forward higher requirements for the performance of aircraft engines. Thermal barrier coating is a surface protection technology and depositing it on the engine turbine blade surface can significantly isolate high temperature and reduce thermal shock and thermal corrosion impact, to ensure the normal operation of aircraft engine turbine blade in harsh and complex environment, and can also significantly improve engine efficiency and service time. The performance of the thermal barrier coating largely affects the bearing and corrosion resistance of the blade, which in turn has an impact on the service capabilities of the aircraft engine. The performance of the coatings is mainly affected by their structure and material system. Firstly, several structural systems of thermal barrier coatings are briefly described in terms of their advantages, disadvantages and research advances. Currently common structural forms include: double-layer structures, multi-layer structures and gradient structures. The classical double-layer structure is still most widely used. The preparation process of multi-layer and gradient structures is more complex and both multi-layer and dual ceramic layer structures are prone to interfacial bonding problems in use, which limits their widespread application. Secondly, the current research status of binder layer materials for thermal barrier coatings is summarized. The current research on MCrAlY alloy and NiAl alloy mainly focuses on the modification of doping elements and MCrAlY alloy still needs to be improved in terms of interfacial bonding and high temperature oxidation resistance, while the advantage of NiAl alloy mainly lies in its creep resistance and oxidation resistance, which can be used as a more ideal binder layer material after modification. At the same time, the research progress of several ceramic layer materials is introduced, such as the doping modification of YSZ, A2B2O7-type compounds, chalcogenide structural materials and several high-entropy ceramic materials that have emerged in recent years. The high-entropy ceramic materials mainly include: high-entropy rare-earth tantalates, high-entropy rare-earth aluminates, high-entropy rare-earth zirconates/hafniumates, high-entropy rare-earth phosphates, high-entropy rare-earth silicates and high-entropy rare-earth oxides, in terms of thermophysical attributes such as thermal cycle life and CTE. Currently, among the doping modifications of YSZ, multi-oxide doping provides more comprehensive performance enhancement. Doping modifications of A2B2O7-type compounds have also yielded good results, but the strength and fracture toughness of the materials need further improvement. Among the high-entropy ceramic materials, high-entropy rare-earth zirconates and high-entropy rare-earth oxides are highly promising materials for ceramic layers. In order to meet the increasing requirements for engine performance, the improvement of the performance of thermal barrier coatings still needs to be continuously explored. Common forms of failure of thermal barrier coatings, such as TGO failure, CMAS corrosion, salt spray corrosion and high temperature sintering, are reviewed and the mechanisms by which they occur are briefly described. Finally, future trends and directions for thermal barrier coatings are presented. In future research, attention should be paid to improving the mechanical properties of coatings, as well as to investigating the mechanisms behind changes in coating performance, and to achieving more accurate predictions of coating life based on current research. © 2023 Chongqing Wujiu Periodicals Press. All rights reserved.