چكيده به لاتين
Superhydrophobic surfaces due to the non-wetting property have wide applications in many industries including Increasing heat transfer by converting filmwise condensation into dropwise condensation, fabrication of self-cleaning, anti-icing, corrosion resistance surfaces and drag reduction systems. Most scientific researches is based on the production of superhydrophobic coatings on aluminum and copper alloys. For example, Aluminum alloys due to good strength, good electrical, thermal conductivities and low specific weight are the most important engineering materials in aerospace, automobile and railways. In this study, a single step anodizing process is used to produce micro-nano structures on aluminum (1050) substrates and Surface energy of the anodized layer is reduced using stearic acid modification. After the anodizing process, the surface is converted to a superhydrophilic surface at a contact angle of about zero degrees then after modification with stearic acid, The surface becomes a superhydrophobic surface. Effects of different parameters including anodizing time, electrical current, and type and concentration of electrolyte on the final contact angle are systemically studied and optimal condition is found. Results show that anodizing time of 90 min, anodizing current of 0.41 A and electrolyte (sulfuric acid) concentration of 15 wt % are optimal conditions which give respectively contact angle and sliding angle as high as 159.2° and 2° . As well as, the study reveals that adding oxalic acid to the sulfuric acid cannot enhance superhydrophobicity of the samples. Also scanning electron microscope, X-ray diffraction and Brunauer–Emmett–Teller (BET) In order to respectively show the surface structure, chemical composition of the oxide layer and surface porosity were used.
