الفهرس 
Part 1Only 14 pages are availabe for public view
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Abstract
Amphoteric metals like aluminum react with both acids and bases chemically. A thin layer of aluminum oxide (5-10 nm) is instantly formed on aluminum’s surface when it reacts spontaneously with water and/or air when freshly produced. As a result, Al anodes are employed as galvanic anodes for cathodic protection (CP) systems. The protective oxide film produces passivity, which allows aluminum to perform well in corrosive environments. Although the protective layer is electrically insulating, somewhat it possesses a high thermal conductivity (30 Wm-1K-1). However, Al alloys often have poor corrosion resistance when exposed to corrosive environments. It is also common for aluminum alloys to degrade at a faster rate in restricted pH ranges. Corrosion rates are extremely low between pH 4 and 7. Nevertheless, corrosion rates are extremely high when pH levels fall below 4 or rise above 7. It would be expected that aluminum alloy corrosion in seawater takes the form of pitting, as the salt content of the water and the high concentration of dissolved oxygen provide sufficient cathodic reactions to polarize the alloys to their pitting potential.
Corrosion of aluminum alloys takes place as a result of the simultaneous anodic and cathodic reactions at the metal surface. Oxidation and reduction take place instantaneously, and electrons are transferred between the two reactants. In essence, these processes take place in the alloy’s microstructure. The microstructure of an aluminum alloy is determined by the alloy elements and by the thermomechanical treatment. However, the metallic phases constructed on the microstructure are not existing in the case of pure aluminum alloy. Consequently, the cathodic reaction is improbable to occur leading to a lessening of the degradation rate.
As a consequence of the ubiquitous corrosion of metals, there are huge financial losses and safety risks that need to be addressed by the development of facile and economical ways to protect the metal surface. As water is the primary cause of metal corrosion, most of the techniques involve strategies that impede water ingress. A bio-mimicking surface was developed to mitigate corrosion on metal surfaces by mimicking naturally occurring surfaces. Specifically fabricated hierarchical structures display liquid-repelling lotus leaf-like behavior by encapsulating air in the structures to constrain the mass transport of water and aggressive species. Various applications of such surfaces have been explained, including self-cleaning, antimicrobial, etc. In chapter one, the basics and theories of the superhydrophobic coatings have been discussed. In addition to superhydrophobicity’s importance for various potential applications is briefly summarized. In chapter 2, the corrosion resistance and the durability of as-fabricated Poly(vinylidene fluoride-co-hexafluoropropylene)/alumina superhydrophobic coatings (SHCs) have been comprehensively explored using variable techniques. In chapter 3, two techniques were employed to fabricate the PVDF-HFP/CNTs SHCs on aluminum alloy and explore their corrosion resistance in saline water as well as the UV durability and anti-fouling formation.