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Bahram Ramezanzadeh - One of the best experts on this subject based on the ideXlab platform.

  • mil 88a fe filler with duplicate corrosion inhibitive barrier effect for epoxy coatings electrochemical molecular simulation and Cathodic Delamination studies
    Journal of Industrial and Engineering Chemistry, 2021
    Co-Authors: Nariman Alipanah, Bahram Ramezanzadeh, H Yari, M Mahdavian, Ghasem Bahlakeh
    Abstract:

    Abstract The MIL-88A (Fe) as a MOF based on Fe+3 cations and fumaric acid was fabricated as a corrosion inhibitive filler to achieve a protective coating with duplicate active/passive inhibition properties. The polarization test indicated that the MIL-88A (Fe) saline-based extract had an inhibition effect. The formation of an inhibitive layer was seen in the EIS results for the sample immersed in the MIL-88A (Fe) extract. The slight solubility of MIL-88A (Fe) in the water (122.4 ppm total organic carbon and 2 ppm Fe+3) caused the inhibitive ions' release. The adsorption of release species from MIL-88A (Fe) scaffold on the substrate was confirmed by the theoretical (QM, MC/MD) computations. The EIS and salt spray test results obtained from scratched epoxy coated samples showed the Epoxy-MIL-88A (Fe) coating's active inhibition effect. The pull-off adhesion strength and Cathodic Delamination resistance were also improved in the presence of MIL-88A (Fe). The adhesion loss of epoxy coatings after 7 days of exposure to the salt spray decreased from 31.4% to 9.4%, respectively. The unscratched samples filled with MIL-88A (Fe) particles showed excellent barrier properties. The breakpoint frequency value declined from 2.4 to 0.8, and the reduction of low-frequency impedance magnitude decreased from 33% to 20%.

  • designing a dual functional epoxy composite system with self healing barrier anti corrosion performance using graphene oxide nano scale platforms decorated with zinc doped conductive polypyrrole nanoparticles with great environmental stability and non toxicity
    Chemical Engineering Journal, 2020
    Co-Authors: Rahman Mohammadkhani, Mohammad Ramezanzadeh, Samaneh Saadatmandi, Bahram Ramezanzadeh
    Abstract:

    Abstract Designing a novel epoxy composite system with dual self-healing/barrier anti-corrosion functions using graphene oxide (GO) nano-platforms decorated by polypyrrole (PPy) nanoparticles doped with zinc metal ions is the major objective of this research attempt. GO-PPy-Zn nanoplatform was fabricated via one-pot polymerization of pyrrole monomers on GO and two direct/indirect methods of zinc doping. In order to verify the PPy nanoparticles synthesis on GO sheets several analyses such as UV–visible, XPS, HR-TEM and FE-SEM were performed. The epoxy nanocomposite coatings containing GO-PPy and GO-PPy-Zn nanoplatforms were fabricated and applied on carbon steel. The nanocomposite coatings anti-corrosion capability was examined by electrochemical impedance spectroscopy (EIS), salt spray and pull-off adhesion test methods. The results of XPS analysis and HR-TEM and FE-SEM images demonstrated the zinc doped PPy nanoparticles formation on the GO nanoplatform. The great potency of GO-PPy-Zn on the epoxy coating anti-corrosion performance promotion, self-healing-barrier properties enhancement and Cathodic Delamination resistance improvement were obtained on carbon steel.

  • development of a nanostructured ce iii pr iii film for excellently corrosion resistance improvement of epoxy polyamide coating on carbon steel
    Journal of Alloys and Compounds, 2019
    Co-Authors: Mohammad Ramezanzadeh, Ghasem Bahlakeh, Bahram Ramezanzadeh
    Abstract:

    Abstract Chemical treatment of carbon steel (CS) specimens was done by an eco-friendly Ce (III)-Pr(III) composite nanofilm. The impact of composite film deposition on CS on the epoxy coating (EP) capability for reduction of CS corrosion and Delamination rates was examined. The Ce (III)-Pr (III) thin film morphology was studied by field emission-scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS) methods. The EP anti-corrosion capacity promotion on CS by deposition of Ce(III)-Pr(III) composite film was investigated by electrochemical impedance spectroscopy (EIS) and salt spray test. Cathodic Delamination (CD) rate of EP/Ce (III)-Pr (III) system was also examined. Furthermore, molecular dynamics (MD) simulations were applied to get microscopic-level insights into the aminoamide hardener/epoxy coating interaction mechanism with Ce (III)-Pr (III) film. It was shown that the film uniformly deposited is mainly composed of oxide/hydroxide of cerium (III) and praseodymium (III) and without crack and defect. Results revealed that the Ce (III)-Pr (III) composite thin film significantly promoted the EP anti-corrosion capability and decreased the CD rate. The computational results proved that the curing agent and crosslinked EP resin adsorbed to praseodymium and cerium oxide surfaces mostly through electrostatic interactions of N and O heteroatoms with surface metal atoms.

  • the epoxy coating interfacial adhesion and corrosion protection properties enhancement through deposition of cerium oxide nanofilm modified by graphene oxide
    Journal of Industrial and Engineering Chemistry, 2018
    Co-Authors: Nafise Parhizkar, Bahram Ramezanzadeh, Taghi Shahrabi
    Abstract:

    Abstract This paper aims at improving the Cathodic disbonding, corrosion protection and adhesion properties of epoxy coating through steel substrate treatment by cerium nanofilm. For this purpose, the cerium film was modified by graphene oxide nanosheets, which are covalently functionalized with silane coupling agent. The performance of this coating was studied by electrochemical impedance spectroscopy, Pull-off adhesion and Cathodic Delamination tests and the morphology of the modified cerium film was investigated by field-emission scanning electron microscopy. Results revealed that modifying the cerium nanofilm led to the better adhesion strength, corrosion protection performance and lower Cathodic Delamination rate of epoxy coating.

  • corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre treated by a sol gel based silane coating filled with amino and isocyanate silane functionalized graphene oxide nanosheets
    Applied Surface Science, 2018
    Co-Authors: Nafise Parhizkar, Bahram Ramezanzadeh, Taghi Shahrabi
    Abstract:

    Abstract This research has focused on the effect of graphene oxide (GO) nano-fillers embedded in the sol-gel based silane coating on the corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by silane coatings. For this purpose, a mixture of Methyltriethoxysilane (MTES) and Tetraethylorthosilicate (TEOS) silane precursors was used for preparation of composite matrix and the GO nanosheets, which are covalently functionalized with 3-(Triethoxysilyl)propyl isocyanate (TEPI, IGO nano-fillers) and 3-aminopropyltriethoxysilane (APTES, AGO nano-fillers), were used as filler. The GO, AGO and IGO nanosheets were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV–Visible analysis and field emission-scanning electron microscopy techniques. The performance of the silane/epoxy coatings was investigated by pull-off adhesion, Cathodic Delamination, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results revealed that AGO and IGO nano-fillers significantly improved the corrosion resistance and adhesion properties of the top epoxy coating due to better compatibility with silane matrix, excellent barrier properties and the formation of covalent bonds with the top epoxy coating.

H N Mcmurray - One of the best experts on this subject based on the ideXlab platform.

  • combinatorial studies into the effect of thermally inter diffused magnesium on the kinetics of organic coating Cathodic Delamination from zinc galvanized steel
    Journal of The Electrochemical Society, 2020
    Co-Authors: N Wint, H N Mcmurray, Zak Barrett, Geraint Williams
    Abstract:

    This paper describes a high-throughput study into the role of Mg in preventing corrosion driven coating disbondment of organic coatings from Zn-Mg alloy galvanized steel. A graded Mg wedge is applied to a hot-dip zinc galvanised steel substrate using physical vapour deposition, and subsequently annealed to produce metallic inter-diffusion and formation of Mg2Zn11 intermetallic. An overcoat of electrically insulating polyvinyl butyral (PVB) is applied and corrosion is initiated from a penetrative coating defect using an aqueous electrolyte. The variation in Mg coating weight across the wedge facilitates a systematic investigation of the effect of Mg on Volta potential and the rate of corrosion driven Cathodic coating disbondment using scanning Kelvin probe (SKP) potentiometry. The rate of Cathodic disbondment is shown to decrease rapidly even at very low Mg coating weight (corresponding to 25 nm thickness before annealing). The results are explained in terms of the galvanic polarity of the corrosion cell formed between Zn exposed at the defect site, and the intact Zn-Mg layer at the metal-organic coating interface.

  • evaluation of multi layered graphene nano platelet composite coatings for corrosion control part ii Cathodic Delamination kinetics
    Corrosion Science, 2018
    Co-Authors: C F Glover, C Richards, Geraint Williams, H N Mcmurray
    Abstract:

    Abstract In-situ Scanning Kelvin probe (SKP) measurements are used to follow the corrosion-driven Cathodic Delamination kinetics of model coatings comprising graphene nano-platelets (GNP) dispersed in polyvinylbutyral (PVB) adherent to iron and zinc (galvanised steel). To reduce Delamination rates by >90% (relative to unpigmented PVB) a GNP volume fraction of 0.056 is required on iron but only 0.028 on zinc. On this basis, together with work function and O 2 permeability data it is proposed that the GNP acts principally to slow through-coating oxygen transport on iron; whereas on zinc a galvanic couple forms between zinc and GNP, displacing Cathodic oxygen reduction.

  • In-coating graphene nano-platelets for environmentally-friendly corrosion protection of iron
    Corrosion Science, 2017
    Co-Authors: C F Glover, C Richards, G Williams, J Baker, H N Mcmurray
    Abstract:

    A primer coating system adherent to iron substrates based on graphene nano-platelets (GNPs) dispersed in polyvinylbutyral (PVB) is presented. Using a scanning Kelvin probe (SKP), the composite coatings are shown to exhibit exceptional resistance to an important corrosion-driven failure process, namely Cathodic Delamination, when aqueous chloride electrolyte is introduced to a penetrating coating defect. Delamination rate kinetics are shown to correlate strongly with reductions in the rate of oxygen permeation through the coating with increasing GNP pigment volume fraction.

  • dopant effects in polyaniline inhibition of corrosion driven organic coating Cathodic Delamination on iron
    Journal of The Electrochemical Society, 2006
    Co-Authors: Geraint Williams, A Gabriel, Angus Cook, H N Mcmurray
    Abstract:

    Coatings comprising various volume fractions of particulate polyaniline dispersed in a polyvinylbutyral binder are applied to iron substrates. A scanning Kelvin probe is used to measure substrate potentials in humid air and follow corrosion-driven coating Delamination (Cathodic disbondment) when 5% w/v (0.86 M) aqueous NaCl contacts a coating defect. Emeraldine base has no effect on substrate potential or Delamination kinetics. Emeraldine salts (ES) doped using p-toluenesulfonic (HpTS), camphorsulfonic (HCS), phosphoric (H 3 PO 4 ), and phenylphosphonic (H 2 PP) acids increase substrate potentials by up to 0.36 V and inhibit Delamination with efficiency order of HpTS < HCS < H 2 PO 4 << H 2 PP. Dopant salts added to the corrosive electrolyte do not inhibit Delamination. It is proposed that inhibition arises primarily from Cathodic O 2 reduction becoming relocated from the ennobled substrate onto the ES coating. However, Fe 3 (PO 4 ) 2 and FePP salt films formed at the ES-substrate interface also contribute by hindering interfacial electron transfer.

  • polyaniline inhibition of corrosion driven organic coating Cathodic Delamination on iron
    Journal of The Electrochemical Society, 2005
    Co-Authors: R J Holness, Geraint Williams, David Worsley, H N Mcmurray
    Abstract:

    The polyaniline emeraldine salt of paratoluenesulfonic acid (PAni-pTS) is dispersed in polyvinylbutyral coatings adherent to an iron surface. Such dispersions are shown to effectively inhibit corrosion-driven coating Delamination (Cathodic disbondment) when 5% w/v (0.86 M) aqueous chloride electrolyte contacts a penetrative coating defect. A scanning Kelvin probe is used to quantify the influence of PAni-pTS volume fraction (Φ p a ) on Delamination rate and the potential of the intact (undelaminated) coated surface (E i n t a c t ). Secondary ion mass spectroscopy and atomic force microscopy are used to determine the time-dependent thickness of an oxide layer developing at the coating-iron interface. At 20°C, high relative humidity (93%), and Φ p a = 0.3, the iron oxide layer grows at a constant rate of 5.6 X 10 - 3 nm s - 1 . E i n t a c t increases monotonically from 0.2 to 0.56 V vs. SHE, and coating Delamination rates decrease by ca. 95% as Φ p a is increased from 0 to 0.25. Addition of 0.01 M Na-pTS to the experimental electrolyte has no effect. An inhibition mechanism is proposed in which through-coating Cathodic O 2 reduction is suppressed by the ennoblement of substrate potentials and the OH - product of O 2 reduction is absorbed through PAni-pTS mediated pH buffering.

Taghi Shahrabi - One of the best experts on this subject based on the ideXlab platform.

Geraint Williams - One of the best experts on this subject based on the ideXlab platform.

  • combinatorial studies into the effect of thermally inter diffused magnesium on the kinetics of organic coating Cathodic Delamination from zinc galvanized steel
    Journal of The Electrochemical Society, 2020
    Co-Authors: N Wint, H N Mcmurray, Zak Barrett, Geraint Williams
    Abstract:

    This paper describes a high-throughput study into the role of Mg in preventing corrosion driven coating disbondment of organic coatings from Zn-Mg alloy galvanized steel. A graded Mg wedge is applied to a hot-dip zinc galvanised steel substrate using physical vapour deposition, and subsequently annealed to produce metallic inter-diffusion and formation of Mg2Zn11 intermetallic. An overcoat of electrically insulating polyvinyl butyral (PVB) is applied and corrosion is initiated from a penetrative coating defect using an aqueous electrolyte. The variation in Mg coating weight across the wedge facilitates a systematic investigation of the effect of Mg on Volta potential and the rate of corrosion driven Cathodic coating disbondment using scanning Kelvin probe (SKP) potentiometry. The rate of Cathodic disbondment is shown to decrease rapidly even at very low Mg coating weight (corresponding to 25 nm thickness before annealing). The results are explained in terms of the galvanic polarity of the corrosion cell formed between Zn exposed at the defect site, and the intact Zn-Mg layer at the metal-organic coating interface.

  • Evaluation of multi-layered graphene nano-platelet composite coatings for corrosion control part II – Cathodic Delamination kinetics
    'Elsevier BV', 2018
    Co-Authors: Geraint Williams, Hamilton Mcmurray
    Abstract:

    In-situ Scanning Kelvin probe (SKP) measurements are used to follow the corrosion-driven Cathodic Delamination kinetics of model coatings comprising graphene nano-platelets (GNP) dispersed in polyvinylbutyral (PVB) adherent to iron and zinc (galvanised steel). To reduce Delamination rates by >90% (relative to unpigmented PVB) a GNP volume fraction of 0.056 is required on iron but only 0.028 on zinc. On this basis, together with work function and O2 permeability data it is proposed that the GNP acts principally to slow through-coating oxygen transport on iron; whereas on zinc a galvanic couple forms between zinc and GNP, displacing Cathodic oxygen reduction

  • evaluation of multi layered graphene nano platelet composite coatings for corrosion control part ii Cathodic Delamination kinetics
    Corrosion Science, 2018
    Co-Authors: C F Glover, C Richards, Geraint Williams, H N Mcmurray
    Abstract:

    Abstract In-situ Scanning Kelvin probe (SKP) measurements are used to follow the corrosion-driven Cathodic Delamination kinetics of model coatings comprising graphene nano-platelets (GNP) dispersed in polyvinylbutyral (PVB) adherent to iron and zinc (galvanised steel). To reduce Delamination rates by >90% (relative to unpigmented PVB) a GNP volume fraction of 0.056 is required on iron but only 0.028 on zinc. On this basis, together with work function and O 2 permeability data it is proposed that the GNP acts principally to slow through-coating oxygen transport on iron; whereas on zinc a galvanic couple forms between zinc and GNP, displacing Cathodic oxygen reduction.

  • The Effect of Phase Continuity on the Cathodic Delamination Resistance of Polyaniline Based Coatings
    'The Electrochemical Society', 2018
    Co-Authors: Natalie Wint, Geraint Williams, Hamilton Mcmurray
    Abstract:

    Organic coatings based on electrically conducting polyaniline emeraldine salts (ES) and electrically insulating polyvinyl butyral (PVB) are applied to an iron substrate. An investigation is made into how ES phase continuity, and in-coating charge percolation, affect the kinetics and mechanism of corrosion driven Cathodic coating Delamination. Bilayer coatings are prepared by solution casting continuous ES films onto the substrate, then overcoating with PVB. These are compared with composite coatings of decreased phase continuity, prepared using ES powders dispersed in PVB. Coating Delamination is followed using scanning Kelvin probe potentiometry and optical spectrophotometry. At ES coating weights 0.05 mg.cm−2 and were greater than for dispersion coatings. The relationship between Cathodic Delamination rate and PAni ES continuity is proposed to depend strongly upon the nature and continuity of the interphase formed between the PAni ES coating and iron, and therefore on the dopant anion identity

  • Inhibition of corrosion driven Delamination on iron by smart-release bentonite cation-exchange pigments studied using a scanning Kelvin probe technique
    Progress in Organic Coatings, 2017
    Co-Authors: Geraint Williams, Hamilton Neil Mcmurray
    Abstract:

    Abstract Low-cost, environmentally friendly, cation exchange pigments derived from naturally occurring bentonite clay are shown to significantly enhance resistance to corrosion-driven Cathodic Delamination in organic coatings adherent to iron surfaces. A scanning Kelvin probe (SKP) is used to study the Delamination kinetics of pigmented and unpigmented poly-vinyl-butyral (PVB)-based coatings applied to polished iron substrates. The bentonite clay is used both in its native form and exhaustively exchanged with a range of divalent alkali earth and trivalent rare earth metal cations. For the best performing divalent cation-exchanged pigment, the dependence of coating Delamination rate on pigment volume fraction is determined and compared with that of a conventional strontium chromate (SrCrO 4 ) inhibitor. An inhibition mechanism is proposed for the bentonite pigments whereby underfilm cation release and subsequent precipitation of sparingly soluble hydroxides reduces the conductivity of the underfilm electrolyte.

Nafise Parhizkar - One of the best experts on this subject based on the ideXlab platform.