Erosion resistance of electroplated nickel coatings on carbon-fibre reinforced plastics

• Ni coatings with compact microstructure and low hardness show a ductile erosion mechanism.
• 30 µm Ni coatings fail by buckling.
• 100 µm Ni coatings show significantly higher lifetimes.
• Higher particle energy lowers time to failure with unchanged erosion mechanism.
• All nickel coatings improve erosion resistance of CFRP by varying degrees.

Due to their favourable mechanical properties and low density in comparison to metallic materials, carbon fibre reinforced plastics (CFRPs) have found substantial use in the manufacturing of aircraft parts. One of the drawbacks, however, which hampers more widespread applications, is the poor resistance of the composites to solid and liquid particle erosion. Protective metallic coatings can increase the lifetime of CFRP components which are exposed to erosion by solid particles. In this work, 30 and 100 µm thick nickel coatings were electroplated on CFRP samples with epoxy resin and PEEK matrices. The erosion resistance of the galvanic coatings was examined at two different impact angles and particle velocities. The coatings showed a predominantly ductile erosion mechanism under all testing conditions. A higher particle velocity did not change this mechanism, but reduced the time to coating failure. At 90° impact angle, the coatings failed through delamination, while this effect was not observed at 20° where failure occurred by local complete removal from the substrate. Coating lifetime could be considerably improved by an increased film thickness.