Evaluation of icephobic coatings—Screening of different coatings and influence of roughness

Icing of wind turbines affects energy production, causes mechanical failures and increases safety hazards in general; hence there is an enormous demand for powerful anti-icing methods. To investigate the icephobic properties of different coatings, ice adhesion measurements were performed with a 0° cone test to determine ice adhesion strengths between coating and ice. Various coatings with different icephobic properties were investigated, e.g., hydrophilic and hydrophobic coatings, sol–gel based coatings containing fluorinated compounds and viscoelastic rubbers, as well as commercially available icephobic products. The coatings currently used on wind turbines showed an adhesion to ice that is comparable to that of bare aluminium; meaning a quite high adhesion to ice. Very low adhesion values were obtained in the case of coatings consisting of viscoelastic elastomers. Additionally, the influence of surface roughness on ice adhesion has been examined. Aluminium pins were chemically and mechanically roughened and their ice adhesion was determined. These pins were further coated with a fluorine-containing coating in order to study the influence of minimized surface energies. Shear stress of those coated pins was considerably reduced, however, rough surfaces showed higher ice adhesion than smooth ones.