The increasing need to reduce weight in aircrafts in order to improve fuel efficiency has promoted the adoption of lightweight materials like CFRPs which are intensively used in aerospace applications due to their strength/weight ratio. Nevertheless, when subjected to erosion caused by sand, dust, volcanic ash, or rain, fibre reinforced polymers suffer wear with mass losses that can be several orders of magnitude higher than steel. In order to avoid severe damage and high maintenance costs, the CFRPs in erosion critical areas such as leading edges of airplanes, the material must be protected against erosion. To this purpose, protective coatings can effectively reduce the erosive wear of CFRP components. Polymeric coatings are widely used in aerospace industry to enhance the erosion resistance of composite materials but their lifetime is limited. Physical Vapour Deposition (PVD) processes offer several advantages as they have already shown good erosion protection in other substrates as metallic components of compressor blades. Additionally, they have already shown their potential to achieve good adhesion on polymeric substrates using low temperature processes.
(PVD) coatings are well known as coatings for tribological applications, including erosion protection on different substrates. Although PVD coatings can be applied on polymer-based substrates to provide metallic aesthetics, there are critical issues to address in order to enable their use as protective coatings on soft substrates. While metallic aesthetic coatings on polymers are typically below 1 micron thick, tribological coatings on metallic substrates are in the range of 2-3 microns thick and temperature and bias voltage is typically applied during processing to increase adhesion.
In this context the overall objective of the WINNER project is to develop erosion-resistant functional coatings for Natural Laminar Flow (NLF) wing skin by using PVD deposition technologies on Carbon Fiber Reinforced Polymers substrates.
