Use of flame-sprayed coatings in anti-icing systems for airfoil structures

Icing is a problem on airfoils that are exposed to cold weather conditions. For example, ice growth on wind turbine blades can decrease the electrical efficiency up to 17% under extreme conditions. This phenomenon occurs on airplane wings, among others. To avoid icing, Nickel-Chromium-Aluminum-Yttrium (NiCrAlY) and Nickel-20 wt.% Chromium (Ni-20Cr) coatings have been deposited by using flame spraying on fiber-reinforced polymer composite plates. Electrical current was supplied to the coatings to increase the substrate temperature by way of Joule heating. The coatings were assessed under free and forced convection conditions at different ambient temperatures, from -20°C to 25°C. At temperatures below 0°C, the temperature on the coating and the substrate surfaces remained above 0°C for both the forced and free convection conditions. A nearly homogeneous temperature distribution over the coating surface was observed. The results may also be used to assess the performance of the flame-sprayed coatings in anti-icing systems.