Transplantation of thermally sprayed coatings

For transplanting internal coatings, such kind of mould insert is coated first. (Photo: IW)

IW | Coatings protect components against wear, heat and corrosion. However, coating of very small inner diameters has not been possible so far. Researchers at the Institute of Materials Science (IW) are working on a solution – the transplantation of thermally sprayed coatings.

The basic principle of thermal spraying is simple: Coating material is melted and accelerated towards the surface to be coated. With the transplantation method, not the finished component is coated but an insert that is placed into the casting mould. The coating is transplanted from the insert onto the component during the die casting process.

The new method facilitates the transplantation of structured coatings without any refinishing as well as internal coating of very small diameters like boreholes. For internal coating, the insert is coated from the outside, since the coating is formed as a negative.

The only problem is: After transplantation, the insert has to be removed from the component. One option are inserts made of salt which can simply be washed away. Researchers at IW are currently investigating in a research project, whether this is technically feasible. 

by Patrick Knödler

Image gallery for this article

  • For transplanting internal coatings, such kind of mould insert is coated first. (Photo: IW)
  • During the die casting process, the coating is transplanted onto the component. (Photo: IW)
  • Step by step – that’s how transplanting thermally sprayed coatings works. (Photos: IW)
  • The new method is also suitable for transplanting structured coatings with high accuracy. (Graphic: IW)