Mishra, BrajendraUsman, Chaudhry Ali2016-05-192022-02-032017-05-182022-02-032016https://hdl.handle.net/11124/170102Includes bibliographical references.2016 Spring.Coatings serve many purposes on metallic surfaces, including tribological coating, anti-static coating, electromagnetic shielding coating, anti-reflective coating, and anti-corrosion. Polymer coatings for corrosion protection of metallic substrates are mostly related to long-term performance needs. In addition to the barrier effect, thecoating must have the ability to inhibit the corrosion process if the protective barrier is disrupted. Incorporating fillers, such as metallic oxides, layered fillers and conducting polymer, improves long termed anti-corrosion along with barrier, mechanical, electrical and optical, rheological, and adhesion properties, and resistance to the environmental degradation. The mechanism of protection of incorporated fillers can be divided into different types: barrier, electrochemical, and self-healing. Further, the anticorrosive paints, containing lead or hexavalent chromium as active pigments, represent a risk to human health and theenvironment. Furthermore, restrictionsimposed by national and international agencies on the use of classical red lead, lead chromate, and zinc chromate, have led towards the development of non-toxic organic and inorganic anticorrosion pigments incorporated in thepolymer. In this thesis,three anti-corrosion fillers were investigated for the protection of carbon steel:(1) Graphene as abarrier filler, (2) Nickel Zinc Ferrites as electrochemical filler, (3) and Poly(ortho-anisidine) doped with heteropolyanions as the self-healing filler. Poly(vinyl butyral) (PVB)/graphene coatings showed improved barrier protection and short-term electrochemical properties for carbon steel. The PVB/graphene nanocomposite coating exhibited lower long-term electrochemical protection due to water uptake. On the other hand, functionalized graphene/PVB coatings improved both electrochemical and barrier properties. Large increase in pore resistance of the functionalized graphene/PVB coatings indicated lower water penetration through the coatings. Furthermore, Polyaniline-functionalized graphene (PA-G)/PVB coatings showed better protection for carbon steel for very long times, compared to unmodified graphene/PVB and functionalized graphene/PVB coatings. The long-term electrochemical properties of ferrites were studied both in solution, and polymer coatings. In solution, the corrosion inhibition was inversely proportional to increasing concentration of cations in ferrites (Zn and Ni). The increased corrosion was attributed to the galvanic corrosion of steel due to the adsorption of metallic cations from the ferrites. In polymer composite coating, increased corrosion protection was observed with increasing ferrite concentration up to 1 wt. percent of ferrites. A mechanism of corrosion protection of steel with ferrites in polymer coatings was demonstrated. The metallic cations traveled to the surface of the polymer coating, forming a protection layer which stopped further corrosion of the substrate. The self-healing coatings were developed by doping poly (o-anisidine) (PoA) with hetero-atoms such as Tungsten silicic acid (TSA), and phosphomolybdic acid (PMA). The doped PoA were further incorporated in PVB to manufacture a composite coating for steel protection. The doped-PoA /PVB coatingexhibited increased positive open circuit potential after 45 hours of immersion compared to that of neat PVB coating. The open circuit profile of doped-PoA /PVB coating further indicated the self-healing mechanism corresponding against the corrosion process.born digitaldoctoral dissertationsengCopyright of the original work is retained by the author.anti-corrosion fillerscarbon steelcoatingscorrosionEISNaClTextEmbargo Expires: 05/18/2017