Varmebarrierbelægninger

Varmebarrierbelægninger, often abbreviated as TBCs, are specialized coatings applied to components exposed to high temperatures, particularly in gas turbine engines. Their primary function is to insulate the underlying substrate, reducing the heat transfer from the hot combustion gases to the metal components. This insulation effect allows the engine to operate at higher temperatures, which in turn increases efficiency and power output. TBCs are typically composed of multiple layers, with a bond coat and a thermally insulating ceramic top coat.

The bond coat, often made of an MCrAlY alloy (where M is nickel, cobalt, or both), adheres the ceramic top coat to the metallic component and provides oxidation resistance. The top coat is usually a yttria-stabilized zirconia (YSZ) ceramic, chosen for its low thermal conductivity, high melting point, and resistance to thermal shock. During operation, the TBC system experiences significant thermal cycling, leading to stresses between the layers. The bond coat plays a crucial role in accommodating these stresses and preventing premature failure of the top coat.

The development and application of TBCs have been critical in advancing gas turbine technology, enabling higher operating temperatures and improved fuel economy in aviation and power generation. Ongoing research focuses on developing TBCs with even better thermal insulation properties, enhanced durability, and improved resistance to erosion and foreign object damage.