Protective coatings for aeroengine blade tips: a review

Good sealing of the gas path is the key to improving the thrust-to-weight ratio and fuel efficiency of an aeroengine, which requires a small radial gap between the rotor blade tips and the corresponding seals to minimize the loss of compressed gas. Due to the extreme conditions in service (e.g., high temperatures of 1500 °C, high pressures of 40 atm, and high linear velocities of 400 m/s), problems, such as wear, oxidation, and hot corrosion at the blade tip, are becoming more and more pronounced. Blade tip protective coatings are an effective way to improve these problems. In this paper, the composition and classification of blade tip protective coatings are summarized. The design concepts and preparation techniques of different blade tip protective coatings are highlighted. The problems of the corresponding blade tip protective coatings and the advantages or disadvantages of the preparation technology are also pointed out. Then, the evaluation means of blade tip protective coatings are concluded. Finally, the development trend of blade tip protective coatings is prospected.