Fibre-reinforced plastics (FRP) with their outstanding stiffness-to-weight ratio are established materials to replace metal components in aerospace and automotive industries for the sake of weight reduction. To improve properties such as wear resistance and thermal conductivity, metallic coatings can be applied to the based-polymer surface. One of the methods used for this purpose is thermal spraying. On the other hand, different studies have shown that the adhesion strength of metallic coatings on polymer surfaces is generally low. In this frame, adhesion strength can be enhanced by roughening the metallic surfaces by sandblasting. However, contamination with the blasting material can take place and in the case of fibre-reinforced plastic materials, the high acceleration of the blasting particles leads to irreparable damage to filaments close to the surface, and thus which weakens the adhesive strength of the subsequent coating. In consequence, a material-sensitive surface pre-treatment is needed to improve the adhesion strength of metallically coated FRP.

In this work, the surface of the carbon fibre-reinforced plastics is pre-treated with pulsed laser-based surface treatment methods. The used process chain consist on pulsed laser pre-treatment of the FRP and process control by HIS cameras. The resulting surface conditions and their effect on the adhesion strength of wire arc sprayed copper coating in pull-off, shear tensile and four-point-bending testing have been systematically characterized. It was found that pulsed laser radiation enabled an increase in adhesion strength of up to 200 % compared to sandblasting reference samples in pull-off tests [1]. Furthermore, the hybrid metal-plastic parts achieved a flexural stress of 1128.0 MPa in four-point-bending test without coating-impairment. After 1000 hours of salt water aging, the copper coating showed surface corrosion effects, while the joining zone remained unaffected.

In addition to the desired increase in adhesion, the long-term durability of the hybrid composite was demonstrated in the form of the intact coating after bending stress and an unaffected interface zone after aging in aggressive media. Whereas the low adhesion strength of the coating previously limited the choice of coating materials, a wide range of other metallic materials can be applied to FRP materials using the proposed process chain.