Forming superhydrophobic structures on various aluminium and composite surfaces

The wettability of liquids on solid surfaces is defined by the contact angle formed between them. The two most important factors affecting the contact angle value are the surface energy and surface roughness of the solid. Surfaces with a contact angle less than 90° are called hydrophilic surfaces, while surfaces with a contact angle between 90° and 150° are called hydrophobic surfaces. Surfaces with a contact angle greater than 150° are called superhydrophobic surfaces. These surfaces continue to be developed in different industrial areas for chemical and physical protection or for different functional purposes. In order to obtain hydrophobic and superhydrophobic surfaces, chemical etching method, which is one of the commonly used methods, was used. The surface roughness of the samples was increased at different etching times by using chemical etching solution containing hydrofluoric acid (HF), hydrochloric acid (HCl), nitric acid (HNO3). The sample surfaces with increased surface roughness were modified with STA containing solution. It is aimed to investigate the surface roughness values of AA5754 aluminium alloy, which is widely used industrially, and AA5754/SiCp composite surfaces by chemical etching at different times and also to investigate the effect of reinforcement ratio increase on surface contact angle in AA5754/SiCp composites. By obtaining superhydrophobic structure on the surfaces of these composite materials, it is aimed to increase the usability of aluminium metal matrix composite (Al MMK) materials in new applications. In the results obtained, it was observed that the surface roughness and contact angle increased with the increase of chemical etching time, and higher contact angle values were obtained with the increase of reinforcement ratio in composite materials.