Development and Technological Characterization of Multi-functional Aeronautical Coating From Lab-Scale to the Relevant Environment

Ice adhesion on critical aircraft surfaces is a serious potential hazard that runs the risk of causing accidents. Frozen contaminants cause rough and uneven surfaces which will disturb smooth air flow and greatly degrade the ability of the wing to generate lift and increasing drag. Amongst icing mitigation systems, passive anti-icing coatings represent a challenge to reduce the ice nucleation and growth, reducing the power consumption of the active de-icing systems and consequently the fuel consumption. In this work the advanced properties and effectiveness of the new multifunctional coating with ice-phobic and aesthetical properties are described. In particular advanced morphological characterizations based on Atomic Force Microscopy and Laser Scanning Microscopy measurements as well as subsequent Power Spectral Density analysis were performed to evaluate the surface roughness. Contact angle measurements were executed in order to determine the wettability and surface free energy as well as work of adhesion in flight conditions. In addition, dynamic analysis of the impact of single water droplets on the new multifunctional coating and the classical livery coating were performed in order to demonstrate the different physical behavior during the impingement. It was also demonstrated that the new multifunctional coating overcome the environmental test similarly to the commercial livery coating in accordance with the aeronautical specification. Finally, two NACA symmetric airfoils were design and developed using 3D printing technology. The surfaces were coated with a commercial coating in one case and with the new multifunctional coating in the other case. Both airfoils were tested in the Icing Wind Tunnel at different conditions in order to evaluate the effectiveness, in terms of reduction of accreted ice, of the new multifunctional coating respect to the commercial one. Tests demonstrated the reduction of accreted ice of 50% using the new multifunctional coating.