In-Flight Ice Accretion Hazard Mitigation with Low Surface Roughness Aluminum Airfoil

Icing is a major problem for the aviation industry, but it has proven to be a difficult problem to solve as the physical processes that lead to icing are complex and interdependent. Recently, it has been shown that a 4X reduction in surface roughness resulted in a 250% decrease in ice-adhesion strength. Super polishing aluminum slurry and pad technology has been used in preliminary tests to polish aluminum airfoils to rms surface roughness levels to 100 nm and below. An aluminum surface polished to 10 nm surface roughness exhibited a 73% reduction in temperature adjusted ice adhesion strength at 1.7 psi. Designed experiments on polishing will be conducted to optimize the surface roughness that yields the lowest ice adhesion strength. Subsequently, the TiN erosion/corrosion coating will also be super polished after deposition to equivalent low surface roughness levels. The manufacturing process can be optimized for time and cost efficiency. A hybrid solution consisting of low surface roughness, a TiN erosion/corrosion coating, and thermal energy is proposed for icing mitigation.