Jump directly to the page contents

Heat shields in gas turbines

Fabrication of the ceramic micro-columns.

This project is concerned with the use of laser-additively manufactured ceramic micropillars as heat shields in gas turbines. Ceramic corrosion and heat protection coatings are an essential technology in the use of metallic materials for components subjected to high temperatures. To compensate for the different expansion behavior of ceramics and metals during temperature changes, these coatings are manufactured with a highly porous or columnar microstructure. Researchers at Forschungszentrum Jülich developed a new variant of laser cladding (Clad2Z) with which they produced ceramic columns in the size range of a few 100 micrometers to several millimeters. By depositing many closely spaced micro-pillars, this additive process produced thermal barrier coatings that, in initial tests under near-operational conditions, showed comparable or higher lifetimes than comparative coatings produced by physical vapor deposition (EB-PVD in this case) or thermal spraying. Compared to these established processes, Clad2Z achieves a high variability of the generated microstructures in the sub-millimeter range with low system engineering effort. This makes it possible to repair localized damage or even flexibly adapt the layer structure on geometrically complex components on-site. Multi-layer arrangements or the use of curved structures offer further possibilities for the generation of complex components as well as the transfer to other fields of application.

Left: gas turbine blades made of ceramic (white) and metal (gray), right: microscopic top view of a protective layer made of Clad2Z ceramic columns, e.g. for use on a gas turbine blade.