Tsunao Tezuka, IHI Corporation, Tokyo, Japan
An aircraft jet engine is composed of a Fan that takes in air and expels it to produce thrust, a Compressor that compresses the incoming air, a Combustion chamber that mixes and burns fuel, and a Turbine that converts the combustion gases into rotational force. Jet engine components are exposed to harsh environment, such as extreme temperatures ranging from below -60 °F to over 2500 °F, vibrations, and centrifugal forces from high-speed rotation. Depending on the part, various functionalities like anti-erosion, anti-wear, anti-corrosion, anti-oxidation, and thermal barrier are needed on the surface. These characteristics, which the base material itself does not possess, are provided by the coatings. The methods to achieve these coatings are diverse, including general techniques such as painting, plating, welding, and air plasma spraying, as well as special techniques such as Metallic Vapor Deposited Diffusion Coating, Vacuum Plasma Spray (VPS), Chemical Vapor Deposition (CVD), and Physical Vapor Deposition (PVD).
Jet engines are increasingly demanding further weight reduction and higher efficiency, and in addition to configuration design, the application of new materials and operation under higher temperature combustion are being implemented. To accommodate new materials and environments, the development of modified or new coating materials and methods is anticipated.