Multilayersystems with Metal Foam

Bildunterschrift Copyright: Fraunhofer ILT Bildunterschrift

The hot gas within combustion chambers of gas turbines can reach temperatures of up to 1500C. In order for the components to resist such thermal loads an effecient cooling is mandatory. One method to supply such cooling is the application of open-porous and high-temperature-resistant metallic foams, which allow a homogeneous leakage of cooling fluid due to a high density of pores. Thermal barrier coating, bond coat and metal foam form a multilayer-system.

The thermal barrier coating of such systems needs to be opened up by laser drilling to enable the flow of the cooling fluid. Percussion drilling can efficiently achieve the necessary holes. The drilling time per hole lies under one second and the drill depths are reproducible. Thus the multilayer-system can be perfused by the cooling fluid as required.