Simin Nosouhian - Department of Materials Engineering, Isfahan University of Technology (IUT), Isfahan, ۸۴۱۵۶۸۳۱۱۱, IRAN
Mohammad Mirzaei - Department of Materials Engineering, Isfahan University of Technology (IUT), Isfahan, ۸۴۱۵۶۸۳۱۱۱, IRAN
Behzad Niroumand - Department of Materials Engineering, Isfahan University of Technology (IUT), Isfahan, ۸۴۱۵۶۸۳۱۱۱, IRAN

Hydrophobic surfaces are of great interest to many industries. Such surfaces tend to repel and minimize their contact with water. This may improve corrosion and wear resistance, prevent icing and minimize fouling and spotting of the surfaces. Surface tension and surface roughness are the main parameters that have been shown to affect the hydrophobicity. Metallic materials have high surface energy and are intrinsically hydrophilic. The most common way to increase the water contact angle on metallic surfaces is through application of hydrophobic coatings. Stabilization of such coatings in industrial environment is a great challenge for scientists. In this work an attempt is made to evaluate the effect of grain size and oxidation on the surface contact angle of pure aluminum. For this purpose a chill test specimen was cast from commercially pure aluminum and the water contact angle at different cross sections of the specimen, with and without oxidation treatment, was measured. The results showed that water contact angle of aluminum surface was affected by grain size and oxidation treatment. The contact angel increased from 50 to 86 degrees by increasing the grain size and to a maximum of 117 degrees by oxidation in air.

Aluminum; Grain size; Hydrophobicity; Contact angle; Surface Energy