Additive manufacturing method for metallic coatings of CFRP propellant tanks

Propellant tanks for rocket stages made of carbon-fibre reinforced plastics (CFRP) need to be lined with a metallic coating (called a liner) on the inside to protect the material from aggressive propellant components and to ensure tightness. Until now, these protective layers have been produced in an expensive manufacturing process by forming and welding thin-walled metal sheets.
Additive Space GmbH is developing a thermal spraying process by which metallic coatings can be applied to the inside of the CFRP structure quickly and cost-effectively. The method enables several layers of metals with different material properties to be applied one after the other with the minimum required layer thickness. Apart from the spraying device, which is mounted on an industrial robot, for example, no further devices adapted to the geometry of the respective fuel tank are required.

Benefits:

• Thermal spray process for very thin coating thicknesses (≤ 100μ) with low mass increase
• Cost / effort reduction, since a metal liner does not have to be produced separately
• No geometric specific devices necessary – universal system use
• Moderate development risk through adaptation of an established procedure
• High scalability
• Wide range of applications