Generation of superhydrophobicity on surface of multiphase aluminum alloy through the combination of ultrasonic cavitation treatment and surface modification

Abstract

The presented study aims to develop a method that combines ultrasonic cavitation and fluorosilane modification for producing superhydrophobic surface on the aluminum alloy substrate. Micro-nano structures are induced through cavitation erosion at different exposure time, and the samples are further modified using a low surface energy modification method. The results show that ultrasonic cavitation is effective for preparing the surface structures required for superhydrophobicity. The water contact angle of about 140° is obtained through an ultrasonic cavitation treatment of 60 min. After surface modification with fluorosilane, the water contact angle increases to 162.5°, and the water sliding angle is reduced to 3.5°. The microscopic phases with high hardness on the aluminum alloy surface are retained, while the microscopic phases with low hardness are removed. Furthermore, the surface hardness is improved by more than 30 %, and work hardening layers of about 200 µm in thickness are produced beneath the target surface.