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    Corrosion Behavior of Hydrophobic Silane Coating Prepared by Sol–gel Method on Carbon Steel

    , M.Sc. Thesis Sharif University of Technology Vaez Ghasemi, Fariba (Author) ; Dolati, Abolghasem (Supervisor)
    This project aims to study corrosion protection performance of silane coating based on tetraethylorthosilicate (TEOS), (3-Mercaptopropyl) trimethoxysilane (MPTS) and Hexamethyldisilazane (HMDS) on carbon steel substrate. Water contact angle (WCA) were measured to study hydrophobicity. The water contact angle increased from 60 degrees in carbon steel to 134.8 degrees in the sample containing 0.35 MPTS and 1.25 HMDS. Surface morphology was studied using Field emission scanning electron microscopy (FESEM) and chemical analysis was conducted using Fourier Transform Infrared Spectroscopy (FTIR). Corrosion resistance was studied by means of Electrochemical Impedance Spectroscopy (EIS) and tafel... 

    Inhibitor-loaded conducting polymer capsules for active corrosion protection of coating defects

    , Article Corrosion Science ; Volume 112 , 2016 , Pages 138-149 ; 0010938X (ISSN) Pirhady Tavandashti, N ; Ghorbani, M ; Shojaei, A ; Mol, J. M. C ; Terryn, H ; Baert, K ; Gonzalez Garcia, Y ; Sharif University of Technology
    Elsevier Ltd 
    This work presents the synthesis of nanostructured hollow polyaniline (PANI) capsules and their application for encapsulation of corrosion inhibitor 2-Mercaptobenzothiazole (MBT). The pH-triggered release of MBT from the capsules was evidenced using UV–vis and Surface Enhanced Raman Spectroscopy (SERS). Incorporation of MBT loaded PANI capsules into epoxy ester coating on AA2024-T3 resulted in a protective system with self-healing ability confirmed by Electrochemical Impedance Spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET). The results showed that the incorporation of MBT-loaded PANI capsules into the coating has significantly improved its corrosion protection... 

    Corrosion Protection of Aluminium by Smart Coatings Containing Layered Double Hydroxide (LDH) Nanocontainers

    , Ph.D. Dissertation Sharif University of Technology Imanieh, Iman (Author) ; Afshar, Abdollah (Supervisor)
    Smart coatings which prevent corrosion by several mechanisms recently have been carefully planned. One of these mechanisms is the use of ion exchangers like Layered Double Hydroxide (LDH) in the coating network. In this study, the LDH containing a kind of green inhibitor (sodium molybdate) was synthesized and utilized in a Poly-Vinyl Alcohol (PVA) base coating applied on the aluminium (5054 series) surface. After evaluating the LDH performance, the inhibitor release from the LDH crystals was examined by changing significant parameters like MII/MIII (the molar ratio of divalent ions into trivalent ions), pH, aging time and temperature. Considering the LDH morphology or the thickness of the... 

    Effect of Oleuropein as Green Inhibitor on Corrosion Protection of Painted Steel

    , M.Sc. Thesis Sharif University of Technology Pourghazian Esfahani, Alireza (Author) ; Ghorbani, Mohammad (Supervisor)
    The corrosion rate of steel (EN 10130 DC-04) in the presence of oleuropein in aqueous corrosive solutions (of different concentrations in 1M and 0.5M hydrochloric acid and also 3.5% sodium chloride) evaluated and results was shown that oleuropein can protect steel surfaces and it acts as good inhibitor. This means that the observations of linear polarization and weight loss experiments showed inhibitor efficiency more than 97% in acidic corrosive medium and above 74% for aqueous solution of 3.5% sodium chloride. Adding oleuropein at different concentrations (i.e. 300 ppm, 700 ppm, and 1000 ppm) to three different types of polymeric paint structures (nitrocellulose alkyd base, acrylic base,... 

    Preparation and Characterization of Anticorrosive Epoxy Coating based on Inhibitor Loaded Metal-Organic Framework Nanostructures

    , M.Sc. Thesis Sharif University of Technology Amouzegar, Mahsa (Author) ; Shojaei, Akbar (Supervisor) ; Molavi, Hossein (Co-Supervisor)
    In this study, metal-organic frameworks (MOFs) UiO-66 and NH2-UiO-66 were prepared and loaded with 2-mercaptobenzothiazole as corrosion inhibitor .Epoxy coatings containing inhibitor loaded nanoparticles were applied on mild steel to corrosion protection in 3.5 wt.% NaCl solution. Fourier transform infrared spectroscopy (FTIR) was used to confirm Inhibitor loading. In order to estimate the loading amount of corrosion inhibitor, thermogravimetric analysis was investigated. FE-SEM images demonstrated nanoparticle dispersibility in epoxy matrix.The results of electrochemical impedance spectroscopy (EIS) alalysis showed improvement of the corrosion resistance of the coatings containing... 

    Quantum electrochemical approaches to corrosion inhibition properties of some aniline derivatives in acidic media

    , Article Journal of the Electrochemical Society ; Volume 154, Issue 8 , 2007 , Pages P93-P100 ; 00134651 (ISSN) Lashgari, M ; Arshadi, M. R ; Sastri, V. S ; Sharif University of Technology
    The molecular behavior of some aniline derivatives as corrosion inhibitors of iron and copper in acidic media (HCl and H2 S O4) were investigated quantum-electrochemically by some recently developed models based on density functional theory and cluster/polarized continuum approaches. In this regard, electrical dipole moment, charges on hetero atoms and acidic hydrogen, electronic chemical potential, and extent of charge transfer were determined for both neutral and protonated forms of molecules inside an electrical double layer and correlated to their inhibitory powers. Good correlations were observed for both acidic media. The results were discussed via ion-pair hypothesis and deprotonation... 

    Evaluation of the corrosion protection properties of an epoxy coating containing sol-gel surface modified nano-zirconia on mild steel

    , Article RSC Advances ; Volume 5, Issue 36 , Mar , 2015 , Pages 28769-28777 ; 20462069 (ISSN) Haddadi, S. A ; Mahdavian, M ; Karimi, E ; Sharif University of Technology
    Royal Society of Chemistry  2015
    In this study, the effect of surface modified nano-zirconia (nano-ZrO2) on the corrosion protection of epoxy coating on mild steel was investigated. An organosilane (trimethoxy methyl silane) was used as a surface modifier to improve the dispersability of the inorganic nanoparticles in the organic coating matrix. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the sol-gel surface modified nanoparticles. The dispersability of the modified and unmodified nano-zirconia in an epoxy coating was examined by field emission-scanning electron microscopy (FE-SEM). Electrochemical impedance spectroscopy (EIS) and salt spray were employed to... 

    PH responsive Ce(III) loaded polyaniline nanofibers for self-healing corrosion protection of AA2024-T3

    , Article Progress in Organic Coatings ; Volume 99 , 2016 , Pages 197-209 ; 03009440 (ISSN) Pirhady Tavandashti, N ; Ghorbani, M ; Shojaei, A ; Gonzalez Garcia, Y ; Terryn, H ; Mol, J. M. C ; Sharif University of Technology
    Elsevier  2016
    Cerium nitrate loaded polyaniline (PANI) nanofibers were synthesized in this work via a chemical route. PANI nanofibers act as a host structure for the corrosion inhibitor, forming a Ce(III)-PANI complex. This complex is pH sensitive, and a change of pH can cause breaking of the complex and releasing of Ce(III). The Ce(III) loaded PANI nanofibers were embedded into epoxy ester coating and the self-healing corrosion protection ability was investigated by Scanning Vibrating Electrode Technique (SVET) and Electrochemical Impedance Spectroscopy (EIS). The results showed that by embedding of Ce(III) loaded PANI nanofibers into the coatings a superior corrosion protection and self-healing... 

    PH-responsive nanostructured polyaniline capsules for self-healing corrosion protection: the influence of capsule concentration

    , Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3512-3520 ; 10263098 (ISSN) Tavandashti, N. P ; Ghorbani, M ; Shojaei, A ; Mol, J. M. C ; Terryn, H ; Gonzalez Garcia, Y ; Sharif University of Technology
    Nanostructured hollow polyaniline (PANI) capsules are good candidates for encapsulation of corrosion inhibitors and pH-responsive release when incorporated into organic coatings. In previous studies, the corrosion protection performance of PANI capsules, containing organic inhibitor 2-Mercaptobenzothiazole (MBT), was demonstrated. The present work studies the influence of capsule concentrations (i.e., 0.3, 1, and 2 wt%) on the corrosion protection properties of the coating system. Anti-corrosion properties of different coatings were compared by means of Electrochemical Impedance Spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET). MBT loaded PANI capsules in epoxy ester... 

    Applications of highly salt and highly temperature resistance terpolymer of acrylamide/styrene/maleic anhydride monomers as a rheological modifier: Rheological and corrosion protection properties studies

    , Article Journal of Molecular Liquids ; Volume 294 , 2019 ; 01677322 (ISSN) Ghaderi, S ; Ramezani Saadat Abadi, A ; Haddadi, A ; Sharif University of Technology
    Elsevier B.V  2019
    Due to the weak performance of commercially affordable natural and synthetic polymeric thickeners in high temperatures and salinity, they fail to use in many applications especially in saline conditions with high temperatures. In this work, a new salt and temperature resistance acrylamide/styrene/maleic anhydride terpolymer (PASM-t) with self-associative properties was synthesized via a one-step inverse emulsion polymerization and its applicability as a rheological modifier and thickener was investigated. The characteristics of synthesized PASM-t (s-PASM-t) and its aqueous solutions were investigated using FT-IR, FE-SEM, GPC and rheometric mechanical spectrometry (RMS) analyses. The... 

    Active Corrosion Protection Application of Conducting Polymer Coating on Steel

    , M.Sc. Thesis Sharif University of Technology Naghavi, Samira (Author) ; Ghorbani, Habib (Supervisor)
    Corrosion is caused through chemical interactions between metal and gases in the surrounding environment. Conductive polymers are used for corrosion protection, polyaniline is the most environmentally stable out of all the conductive polymers, the most studied of this materials, is highly stable, synthesized easily, highly conducting, and readily converted between its various oxidation states.
    In this study we prepared nanoporous polyaniline coating on carbon steel to corrosion protection. Coating was included nanopouros polyaniline with doping molybdate (PANI-MoO_4^(-2)). To increase adhesion between steel and PANI-MoO_4^(-2) layer, oxalic acid was used. Polystyrene nanoparticle layer... 

    Titania nanostructured coating for corrosion mitigation of stainless steel

    , Article Protection of Metals and Physical Chemistry of Surfaces ; Vol. 50, issue. 3 , 2014 , p. 371-377 Barati, N ; Sani, M. A. F ; Sadeghian, Z ; Ghasemi, H ; Sharif University of Technology
    Anatase nanostructured coating has been prepared on 316 L stainless steel by sol-gel dip coating. The topography of the coatings surface has been analyzed using atomic force microscopy. The anticorrosion performance of the coatings has been evaluated using polarization curves. Effects of calcination temperature, withdrawal speed and times of coating on corrosion protection have been studied. The results showed calcination temperature of 400°C and withdrawal speed of 10 cm/min are desirable conditions to achieve high corrosion protection of 316 L stainless steel in chloride containing environments. Coatings with 3 times exhibit better resistance against corrosion in 0.5 molar NaCl solutions.... 

    Microstructural evolution and mechanical properties of semisolid stir welded zinc AG40A die cast alloy

    , Article Journal of Materials Processing Technology ; Volume 209, Issue 8 , 2009 , Pages 4112-4121 ; 09240136 (ISSN) Narimannezhad, A ; Aashuri, H ; Kokabi, A. H ; Khosravani, A ; Sharif University of Technology
    A high quality joint of zinc based pressure die cast alloys can be hardly achieved by conventional fusion welding. In this study, a novel technique to achieve the globular weld structure using stirring the localized semisolid zone during butt joining of Zamak-3 pressure die cast alloy is proposed and effect of welding parameters on mechanical and microstructural properties are investigated. A gas heating system was designed to heat up the nitrogen gas to desired temperature accurately to create a localized semisolid pool. At this stage a fine stirrer was introduced into the weld seam in order to mix the two sides into a single uniform joint. By presented process, globular microstructure of... 

    Epoxy nanocomposite coatings with enhanced dual active/barrier behavior containing graphene-based carbon hollow spheres as corrosion inhibitor nanoreservoirs

    , Article Corrosion Science ; Volume 185 , 2021 ; 0010938X (ISSN) Haddadi, S. A ; Ramazani Saadatabadi, A ; Mahdavian, M ; Arjmand, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Graphene-based carbon hollow spheres (CHSs) fabrication, doped with 2-mercaptobenzimidazole (MBI) was successfully done in previous work. The active/barrier corrosion protection performance (CPP) of epoxy coatings was evaluated using salt spray test, electrochemical impedance spectroscopy (EIS), and scanning vibrating electrode technique (SVET). Results proved the active/barrier CPP enhancement of epoxy coatings in the presence of 3 wt. % MBI@CHSs. While the presence of MBI and empty CHSs in epoxy coatings did not further improve the active performance. An improvement in the adhesion loss of the epoxy coating, ca. 58 %, was observed in the presence of 3 wt. % MBI@CHSs. © 2021  

    Fabrication and characterization of graphene-based carbon hollow spheres for encapsulation of organic corrosion inhibitors

    , Article Chemical Engineering Journal ; Volume 352 , 2018 , Pages 909-922 ; 13858947 (ISSN) Haddadi, S. A ; Ramazani, S. A. A ; Mahdavian, M ; Taheri, P ; Mol, J. M. C ; Sharif University of Technology
    Elsevier B.V  2018
    In this work, we synthesized carbon hollow spheres (CHSs) using the silica templating method, encapsulated 2-mercaptobenzimidazole (MBI) inhibitor in the CHSs and evaluated their corrosion inhibition performance upon exposure of mild steel to a saline solution containing the released inhibitor. The effects of silica template surface modification on the CHS structure was evaluated, while the structure and morphology of the synthesized CHS was analyzed using field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), Raman spectroscopy and X-ray diffraction (XRD) spectroscopy. Furthermore, thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy... 

    Effect of pH and carbon nanotube content on the corrosion behavior of electrophoretically deposited chitosan-hydroxyapatite-carbon nanotube composite coatings

    , Article Ceramics International ; Volume 39, Issue 5 , July , 2013 , Pages 5393-5402 ; 02728842 (ISSN) Batmanghelich, F ; Ghorbani, M ; Sharif University of Technology
    In the first stage, chitosan (CH)-hydroxyapatite (HA)-multiwalled carbon nanotube (MWCNT) composite coatings were synthesized by electrophoretic deposition technique (EPD) on 316L stainless steel substrates at different levels of pH and characterized by X-ray diffraction (XRD), Raman spectroscopy, FTIR and field emission scanning electron microscopy (FESEM). A smooth distribution of HA and MWCNT particles in a chitosan matrix with strong interfacial bonding was obtained. In the next stage, effects of pH and MWCNT content of the suspension on the corrosion behavior and deposition mechanism were studied. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) curves... 

    The effect of sol-gel surface modified silver nanoparticles on the protective properties of the epoxy coating

    , Article RSC Advances ; Volume 6, Issue 23 , 2016 , Pages 18996-19006 ; 20462069 (ISSN) Ghazizadeh, A ; Haddadi, S. A ; Mahdavian, M ; Sharif University of Technology
    Royal Society of Chemistry  2016
    In this study, the effect of surface modified silver nanoparticles on the corrosion protection of an epoxy coating on mild steel was studied. An organosilane (3-methoxy silyl propyl metacrylate) was used as a surface modifier to increase the dispersability of the inorganic nanoparticles in the organic epoxy coating matrix. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the surface modified nanoparticles. Differential scanning colorimetry (DSC) was employed to study the effects of modified and unmodified nano-silver on the curing heat and glass transition temperature of the epoxy coatings. Salt spray and electrochemical impedance... 

    Electrophoretic deposition of nano-zirconia coating on AZ91D magnesium alloy for bio-corrosion control purposes

    , Article Surface and Coatings Technology ; Volume 311 , 2017 , Pages 182-190 ; 02578972 (ISSN) Amiri, H ; Mohammadi, I ; Afshar, A ; Sharif University of Technology
    Elsevier B.V  2017
    Magnesium alloys are considered as potential biodegradable biomaterials in hard tissue implants. However, the fast degradation rate of these alloys in the biological environment causes failure of the implant just prior to the desirable time. In the present work, in order to decrease and curb the bio-corrosion rate of AZ91D Magnesium alloy, zirconia, which is classified as a biocompatible ceramic, was coated on the alloy surface through electrophoretic deposition (EPD) technique. The effects of alterations in the EPD parameters such as current density, duration time and ZrO2 particles concentration on coating properties including thickness, morphology and adhesion were then characterized.... 

    Self-healing epoxy nanocomposite coatings based on dual-encapsulation of nano-carbon hollow spheres with film-forming resin and curing agent

    , Article Composites Part B: Engineering ; Volume 175 , 2019 ; 13598368 (ISSN) Haddadi, S. A ; Ramazani S.A., A ; Mahdavian, M ; Taheri, P ; Mol, J. M. C ; Gonzalez Garcia, Y ; Sharif University of Technology
    Elsevier Ltd  2019
    The ability of an active protective organic coating to restore its protection functionality in case of a coating defect is of pivotal importance to ensure durable performance under demanding corrosive conditions. In this paper, a self-healing epoxy system is fabricated by separate encapsulation of epoxy and polyamine in carbon hollow spheres (CHSs) and the autonomous healing performance of the system applied on mild steel is investigated. CHSs were synthesized via a silica templating method using carbonization of polysaccharide shells formed on the surface of silica templates. Consequently, epoxy and polyamine were loaded in separate capsules by dispersion of CHSs into the dilute solutions... 

    In vitro bioactivity and corrosion resistance enhancement of Ti-6Al-4V by highly ordered TiO 2 nanotube arrays

    , Article Journal of the Australian Ceramic Society ; Volume 55, Issue 1 , 2019 , Pages 187-200 ; 25101560 (ISSN) Sarraf, M ; Sukiman, N. L ; Bushroa, A. R ; Nasiri Tabrizi, B ; Dabbagh, A ; Abu Kasim, N. H ; Basirun, W. J ; Sharif University of Technology
    Springer International Publishing  2019
    In the present study, the structural features, corrosion behavior, and in vitro bioactivity of TiO 2 nanotubular arrays coated on Ti–6Al–4V (Ti64) alloy were investigated. For this reason, Ti64 plates were anodized in an ammonium fluoride electrolyte dissolved in a 90:10 ethylene glycol and water solvent mixture at room temperature under a constant potential of 60 V for 1 h. Subsequently, the anodized specimens were annealed in an argon gas furnace at 500 and 700 °C for 1.5 h with a heating and cooling rate of 5 °C min −1 . From XRD analysis and Raman spectroscopy, a highly crystalline anatase phase with tetragonal symmetry was formed from the thermally induced crystallization at 500 °C....