Nanosecond laser micro-structuring of epoxy painting surfaces adhering to an aluminum alloy

The painting materials and their thickness coated on the airframe of an aircraft would affect the overall weight of the aircraft as well as effectiveness of the protection of the airframe. Epoxy is one of the most popularly used painting materials widely used in the aviation industry for the airframes, and capable of providing a high resistance to chemicals, has less color fading and lower attendance to oxidation. It does not break down easily and adheres onto Aluminum alloys well. At the same time, avoiding icing on the epoxy paintings at different flight altitudes and/or in high latitude countries is essential. In this study, a series of micro-structure patterns were created on the Epoxy painting surfaces using high-precision nanosecond laser machining. These micro-structures are of superhydrophobic characteristics that lead to an improvement of the anti-ice and anti-fog capability and render self-cleaning and water-adhesion reduction functionalities. For the cases investigated, the optimal processing parameters for creating superhydrophobic surfaces on the Epoxy painting material have been found to be: 2W of the Laser power, 100 kHz of frequencies, 10 um of pitch size and 15 um of spot size. Icing experiments have also been conducted, in order to confirm the performance of the micro-structures created as well as to establish the delays of the freezing time. The results showed that the best superhydrophobic surface could delay the time of freezing by 28%, comparing to those with normal epoxy painting surfaces without artificially created micro-structures.