Lämpönsiirtokerrosten

Lämpönsiirtokerrokset, often translated as thermal barrier coatings (TBCs), are specialized materials applied to components in high-temperature environments, primarily in gas turbines and jet engines. Their main function is to reduce the heat transfer from the hot combustion gases to the underlying metal substrate. This thermal insulation allows engine components to operate at higher temperatures, leading to increased efficiency, power output, and component lifespan.

These coatings typically consist of two main layers. The bond coat, usually made of an alloy like MCrAlY (where M is nickel, cobalt, or both), is applied directly to the metal surface. Its purpose is to provide oxidation resistance, improve adhesion to the substrate, and accommodate thermal expansion mismatches. The top layer, known as the ceramic top coat, is the primary thermal insulator. It is commonly made of yttria-stabilized zirconia (YSZ) or other ceramic materials due to their low thermal conductivity and high melting point.

The application of TBCs is a critical manufacturing process. Techniques such as plasma spraying, electron beam physical vapor deposition (EB-PVD), and air plasma spraying (APS) are employed to deposit these layers. The specific method chosen depends on the desired coating properties, such as porosity, microstructure, and adhesion.

By protecting critical engine parts from excessive heat, TBCs play a vital role in the performance and durability of advanced gas turbine engines used in aviation and power generation. Research continues to focus on developing new TBC compositions and application methods to further enhance their thermal insulation capabilities and resistance to degradation mechanisms like erosion and oxidation.