Construction of a Controllable Hydrophobic and Hydrophilic Shot Blasting Technique for Aluminum

In recent years, many problems have arisen, such as increased power consumption in commercial refrigerators due to water droplets on aluminum alloy surfaces, increased frost formation due to bacteria and mold, and increased transportation costs for bullet trains. To solve these problems, we turned our attention to surface texturing technology and shot blasting, a new surface component that can switch between hydrophobic and hydrophilic properties. Shot blasting can be applied to large areas at a lower cost than laser processing and can be used for surface texturing. This study reports the results of an evaluation of the effect of shot blasting on the surface wettability of aluminum alloys. Shot blasting was performed on aluminum alloy A5052 using various particles, and the wettability of the specimens was evaluated. It was found that the wettability after shot blasting varied with the particle material and particle size as in previous studies. Using the aspect ratio (dent depth/dent width) calculated from the surface roughness, it was found that the specimens became hydrophilic to hydrophobic up to an aspect ratio of 7 or less, and that the contact angle gradually increased to hydrophobic at an aspect ratio of 7 or greater.