Thermal spray coating of Aeroengine

       Thermal spray coatings for aero-engines mainly include wear-resistant coatings, thermal barrier coatings, sealing coatings and high-temperature protective coatings.

  1. Wear-resistant coating

  Due to the harsh working conditions (high temperature, high speed, vibration and high load) of aero engine parts, and several types of wear such as adhesion, abrasive particles, corrosion and fatigue, the performance and service life of the engine are affected.

  2. Sealed coating

  Aviation gas turbine engines have relatively complete gas path sealing systems. The system consists of 40-60 sealing devices between the shaft, drum, blade tip, compressor and turbine. The quality of the sealing device directly affects the power, thrust and efficiency of the engine. For example, in the sealing industry of the turbine outer ring (that is, the radial blade tip clearance), according to the design requirements, every 1% increase in the ratio of the blade tip clearance to the blade length, the turbine efficiency loss increases by 1% to 3%. It can be seen that tight air circuit sealing is one of the important ways to improve efficiency and performance. For this reason, an abradable sealing coating is often used in design to achieve the purpose of sealing the gas path.

Thermal spray sealing coatings are divided into two categories, namely active grinding coatings and abradable coatings (passive).

  (1) The active grinding coating (abrasive) is generally a hard wear-resistant gray alumina coating, sprayed on the sealed grate. With the high-speed rotation of the rotor, it grinds the corresponding metal honeycomb seal group like a grinding wheel, and tries to protect itself from wear. This requires the coating to have high bonding strength, high hardness and good heat insulation performance.

  (2) The abradable coating requires that the coating is soft and easy to wear, and has the performance of moisturizing, impact resistance, thermal vibration resistance, and good bonding performance with the substrate, accompanied by plasma spraying technology and related supporting systems The further development of plasma spraying technology will be more widely used in aero engine coating products.