Ceramics and metals on CFRPs or other polymeric based composites

Coatings on CFRP add functions that the polymer matrix cannot provide itself, such as thermal insulation, wear and erosion resistance and electrical heating, and thereby widen the use of lightweight composites in aircraft and other vehicles. The main challenge is the limited thermal stability of the epoxy matrix (typically about 120 to 180 °C) and the risk of fibre damage by hot or fast particles. Low-heat-input processes such as cold spray, arc or flame spraying of low-melting metals (Zn, Sn, Al) and plasma spraying with substrate cooling are therefore used, often on a metallic or polymer-based interlayer that protects the fibres and improves adhesion. Ceramic and metal-ceramic functional layers can be built on this base, although most of these systems are still at research or qualification stage. Typical components are wing and rotor leading edges, nacelles, engine surroundings and structural parts under contact loads; further functions such as lightning-strike protection and EMI shielding follow the same approach.