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M M Attar - One of the best experts on this subject based on the ideXlab platform.

  • studying the corrosion resistance and hydrolytic degradation of an Epoxy Coating containing zno nanoparticles
    Materials Chemistry and Physics, 2011
    Co-Authors: Bahram Ramezanzadeh, M M Attar
    Abstract:

    Abstract Epoxy nanocomposites containing different contents of Nano-ZnO particles were prepared. The nanocomposites were exposed to 3.5 wt% NaCl solution up to 60 days. Mechanical properties of the nanocomposites (before and after exposure to NaCl solution) were studied by dynamic mechanical thermal analysis (DMTA) and nano-indentation techniques. Fourier transform infrared spectroscopy (FTIR) was utilized to investigate hydrolytic degradation of Coatings. Corrosion resistance of the composites was studied by an electrochemical impedance spectroscopy (EIS). Results showed that blank sample was severely deteriorated after exposure to corrosive electrolyte. Corrosion resistance of the Epoxy Coating was significantly improved using nanoparticles. The cross-linking density and indentation hardness of the blank sample were significantly decreased after exposure to corrosive electrolyte. Results showed that nanoparticles could significantly improve Coating resistance against hydrolytic degradation. Results revealed that decrease in cross-linking density and indentation hardness of the Epoxy Coatings containing 3.5 and 5 wt% nanoparticles were not significant. Decrease in adhesion loss was also obtained using nanoparticles.

  • the role of zinc aluminum phosphate anticorrosive pigment in protective performance and cathodic disbondment of Epoxy Coating
    Corrosion Science, 2010
    Co-Authors: R Naderi, M M Attar
    Abstract:

    Protective performance and cathodic disbondment of Epoxy Coating pigmented with zinc aluminum phosphate (ZPA) were studied in this work. In solution, superior corrosion inhibition of ZPA extracted from EIS and electrochemical noise data was connected to deposition of a protective layer. EIS evaluation of the pigmented Coatings indicated significant effect of modification of zinc phosphate on the protective performance as well as resistance to cathodic disbonding. Compared to ZPA, introduction of zinc phosphate resulted in inferior performance in cathodic disbonding test. In presence of ZPA, precipitation at disbonding front inferred from EIS data was confirmed by SEM.

  • the role of zinc aluminum phosphate anticorrosive pigment in protective performance and cathodic disbondment of Epoxy Coating
    Corrosion Science, 2010
    Co-Authors: R Naderi, M M Attar
    Abstract:

    Protective performance and cathodic disbondment of Epoxy Coating pigmented with zinc aluminum phosphate (ZPA) were studied in this work. In solution, superior corrosion inhibition of ZPA extracted from EIS and electrochemical noise data was connected to deposition of a protective layer. EIS evaluation of the pigmented Coatings indicated significant effect of modification of zinc phosphate on the protective performance as well as resistance to cathodic disbonding. Compared to ZPA, introduction of zinc phosphate resulted in inferior performance in cathodic disbonding test. In presence of ZPA, precipitation at disbonding front inferred from EIS data was confirmed by SEM.

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Jelena B. Bajat - One of the best experts on this subject based on the ideXlab platform.

  • The protective properties of Epoxy Coating electrodeposited on Zn–Mn alloy substrate
    Progress in Organic Coatings, 2015
    Co-Authors: M. Bučko, Vesna Mišković-stanković, Jelena Rogan, Jelena B. Bajat
    Abstract:

    Abstract The Epoxy Coating was cataphoretically deposited on steel and steel modified by electroplated Zn–Mn alloy of different chemical contents. The samples were immersed in 0.5 mol dm −3 NaCl solution for 60 days. The electrochemical impedance spectroscopy (EIS) analysis showed that the values of pore resistance for Epoxy Coating on steel and Zn–Mn alloy with 16 at.% Mn were two orders of magnitude higher, while the capacitance values were two orders of magnitude lower than those for the Epoxy Coating on Zn–Mn alloy substrates with 5 and 8 at.% Mn. It was assumed that the main reason for such a difference was metallic substrate dissolution during cataphoretic deposition, due to high pH (12.9). This assumption was supported by energy dispersive X-ray spectrometry (EDS) measurements showing that the amount of released Zn in Epoxy Coatings decreased as Mn percent in the Zn–Mn alloys increased. In addition, Zn–Mn alloy Coatings on steel, as well as bare steel, were immersed in 0.1 mol dm −3 NaOH solution, pH 12.9, simulating conditions during cataphoretic deposition, and polarization resistance measurement in this solution indicated that Mn inclusions in Zn–Mn alloy substrate prevent Zn dissolution in alkaline medium.

  • Studies on adhesion characteristics and corrosion behaviour of vinyltriethoxysilane/Epoxy Coating protective system on aluminium
    Applied Surface Science, 2010
    Co-Authors: Jelena B. Bajat, Ingrid Milosev, Željka Jovanović, Vesna Mišković-stanković
    Abstract:

    Abstract The corrosion stability of vinyltriethoxysilane/Epoxy Coating protective system on aluminium is strongly related to the strength of bonds forming at the metal/organic Coating interface. This article is a study of adhesion, composition, electrochemical and transport properties of Epoxy Coatings electrodeposited on bare aluminium and aluminium pretreated by vinyltriethoxysilane (VTES) during exposure to 3% NaCl. The VTES film was deposited on aluminium surface from 2% vinyltriethoxysilane solution during 30 s. From the values of adhesion strength (pull-off test), time dependence of pore resistance and Coating capacitance of Epoxy Coating (impedance measurements) and diffusion coefficient of water through Epoxy Coating (gravimetric liquid sorption measurements), the influence of VTES sublayer on the corrosion stability of the electrodeposited Epoxy Coating was shown. The work discusses the role of the VTES pretreatment in the enhanced adhesion and corrosion stability of Epoxy cataphoretic Coating. The electrochemical results showed that the aluminium pretreatment by VTES film improved barrier properties of Epoxy Coating (greater pore resistance and lower Coating capacitance). The lower value of diffusion coefficient of water through Epoxy Coating indicates the lower porosity, while the smaller adhesion reduction points to better adhesion of Epoxy Coating on aluminium pretreated by VTES film. The composition of the deposited Coatings investigated by XPS enabled the clarification of the bonding mechanism.

  • the influence of zinc surface pretreatment on the adhesion of Epoxy Coating electrodeposited on hot dip galvanized steel
    Progress in Organic Coatings, 2007
    Co-Authors: Jelena B. Bajat, V Miskovicstankovic, N Bibic, D M Dražic
    Abstract:

    The adhesion and electrochemical properties of Epoxy Coatings electrodeposited on hot-dip galvanized steel with and without passive films were investigated during exposure to 3% NaCl. The passive films were formed in hot air, in boiling water and by chromating. Adhesion was measured both by a standardized pull-off method and by swelling in N-methyl pyrrolidone. Pretreatment of hot-dip galvanized steel with passive film formed in hot air increases both dry and wet adhesion strength of the Epoxy Coating compared to pretreatment with passive film formed in boiling water and chromate Coating. The overall increase of wet adhesion for this sample was maintained throughout the whole investigated time period. It was shown that the change in adhesion of Epoxy Coating on a chromate Coating is smallest of all investigated samples, although the initial value of adhesion on this surface had the lowest value. The corrosion stability of coated Zn samples pretreated by different methods, was investigated by electrochemical impedance spectroscopy and in the initial time of exposure to NaCl the highest values of pore resistance were also obtained for the Epoxy Coating on Zn pretreated in hot air, whereas the Epoxy Coating on a HDG steel with a chromate Coating showed the smallest change in electrochemical properties (pore resistance, Coating capacitance, charge-transfer resistance) during prolonged exposure time.

  • The influence of steel surface modification by electrodeposited Zn-Fe alloys on the protective behaviour of an Epoxy Coating
    Progress in Organic Coatings, 2003
    Co-Authors: Jelena B. Bajat, Vesna Mišković-stanković, Zorica Kačarević-popović
    Abstract:

    Abstract The electrochemical and transport properties of Epoxy Coatings electrodeposited on steel and steel modified by Zn–Fe alloys were investigated during exposure to 3% NaCl. The Zn–Fe alloys were deposited on steel surface from alkaline bath galvanostatically using different current densities. From the time dependence of pore resistance of Epoxy Coating (impedance measurements), diffusion coefficient of water through Epoxy Coating (gravimetric liquid sorption measurements) and water content in the Epoxy Coating (thermogravimetric analysis), it was shown that Zn–Fe sublayer could improve the corrosion stability of the protective system based on Epoxy Coating. The values of the pore resistance were almost unchanged over the long period of immersion time for Epoxy Coating on steel modified by Zn–Fe alloy deposited by 4 A dm −2 , indicating the great stability of this protective system. The values of diffusion coefficient of water through Epoxy Coating on this alloy and water content inside the Epoxy Coating were the smallest, indicating the low porosity of the Coating.

Mohammad Mahdavian - One of the best experts on this subject based on the ideXlab platform.

Vesna Mišković-stanković - One of the best experts on this subject based on the ideXlab platform.

  • The protective properties of Epoxy Coating electrodeposited on Zn–Mn alloy substrate
    Progress in Organic Coatings, 2015
    Co-Authors: M. Bučko, Vesna Mišković-stanković, Jelena Rogan, Jelena B. Bajat
    Abstract:

    Abstract The Epoxy Coating was cataphoretically deposited on steel and steel modified by electroplated Zn–Mn alloy of different chemical contents. The samples were immersed in 0.5 mol dm −3 NaCl solution for 60 days. The electrochemical impedance spectroscopy (EIS) analysis showed that the values of pore resistance for Epoxy Coating on steel and Zn–Mn alloy with 16 at.% Mn were two orders of magnitude higher, while the capacitance values were two orders of magnitude lower than those for the Epoxy Coating on Zn–Mn alloy substrates with 5 and 8 at.% Mn. It was assumed that the main reason for such a difference was metallic substrate dissolution during cataphoretic deposition, due to high pH (12.9). This assumption was supported by energy dispersive X-ray spectrometry (EDS) measurements showing that the amount of released Zn in Epoxy Coatings decreased as Mn percent in the Zn–Mn alloys increased. In addition, Zn–Mn alloy Coatings on steel, as well as bare steel, were immersed in 0.1 mol dm −3 NaOH solution, pH 12.9, simulating conditions during cataphoretic deposition, and polarization resistance measurement in this solution indicated that Mn inclusions in Zn–Mn alloy substrate prevent Zn dissolution in alkaline medium.

  • Studies on adhesion characteristics and corrosion behaviour of vinyltriethoxysilane/Epoxy Coating protective system on aluminium
    Applied Surface Science, 2010
    Co-Authors: Jelena B. Bajat, Ingrid Milosev, Željka Jovanović, Vesna Mišković-stanković
    Abstract:

    Abstract The corrosion stability of vinyltriethoxysilane/Epoxy Coating protective system on aluminium is strongly related to the strength of bonds forming at the metal/organic Coating interface. This article is a study of adhesion, composition, electrochemical and transport properties of Epoxy Coatings electrodeposited on bare aluminium and aluminium pretreated by vinyltriethoxysilane (VTES) during exposure to 3% NaCl. The VTES film was deposited on aluminium surface from 2% vinyltriethoxysilane solution during 30 s. From the values of adhesion strength (pull-off test), time dependence of pore resistance and Coating capacitance of Epoxy Coating (impedance measurements) and diffusion coefficient of water through Epoxy Coating (gravimetric liquid sorption measurements), the influence of VTES sublayer on the corrosion stability of the electrodeposited Epoxy Coating was shown. The work discusses the role of the VTES pretreatment in the enhanced adhesion and corrosion stability of Epoxy cataphoretic Coating. The electrochemical results showed that the aluminium pretreatment by VTES film improved barrier properties of Epoxy Coating (greater pore resistance and lower Coating capacitance). The lower value of diffusion coefficient of water through Epoxy Coating indicates the lower porosity, while the smaller adhesion reduction points to better adhesion of Epoxy Coating on aluminium pretreated by VTES film. The composition of the deposited Coatings investigated by XPS enabled the clarification of the bonding mechanism.

  • Corrosion behavior of duplex polyaniline/Epoxy Coating on mild steel in 3% NaCl
    Chemical Industry, 2005
    Co-Authors: Milica M. Gvozdenović, Zorica Kačarević-popović, Branimir N. Grgur, Vesna Mišković-stanković
    Abstract:

    The corrosion behavior and thermal stability of Epoxy Coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI) film were investigated by electrochemical impedance spectroscopy (EIS) and thermo gravimetric analysis (TGA). The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-Epoxy Coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of the Coating. PANI film was deposited electrochemically on mild steel from an aqueous solution of 0.5 mol dm"3 sodium benzoate and 0.1 mol dm"3 aniline at a constant current density of 1.5 mA cm"2. Non-pigmented Epoxy Coatings on mild steel and on mild steel with PANI film were obtained by cathodic electrode position at constant voltage and stirring conditions. The resin concentration in the electrode position bath was 10 wt.% solid dispersion in water at pH 5.7. The applied voltage was 250 V, the temperature 26°C and the deposition time 3 min. It was shown that thin PANI film could be used to modify the surface of mild steel prior to Epoxy Coating deposition, due to the increased corrosion protection of a duplex PANI/Epoxy Coating comparing to an Epoxy Coating on mild steel in 3% NaCl solution.

  • The influence of steel surface modification by electrodeposited Zn-Fe alloys on the protective behaviour of an Epoxy Coating
    Progress in Organic Coatings, 2003
    Co-Authors: Jelena B. Bajat, Vesna Mišković-stanković, Zorica Kačarević-popović
    Abstract:

    Abstract The electrochemical and transport properties of Epoxy Coatings electrodeposited on steel and steel modified by Zn–Fe alloys were investigated during exposure to 3% NaCl. The Zn–Fe alloys were deposited on steel surface from alkaline bath galvanostatically using different current densities. From the time dependence of pore resistance of Epoxy Coating (impedance measurements), diffusion coefficient of water through Epoxy Coating (gravimetric liquid sorption measurements) and water content in the Epoxy Coating (thermogravimetric analysis), it was shown that Zn–Fe sublayer could improve the corrosion stability of the protective system based on Epoxy Coating. The values of the pore resistance were almost unchanged over the long period of immersion time for Epoxy Coating on steel modified by Zn–Fe alloy deposited by 4 A dm −2 , indicating the great stability of this protective system. The values of diffusion coefficient of water through Epoxy Coating on this alloy and water content inside the Epoxy Coating were the smallest, indicating the low porosity of the Coating.

  • Corrosion protection of aluminium by a cataphoretic Epoxy Coating
    Progress in Organic Coatings, 1999
    Co-Authors: Vesna Mišković-stanković, M.r. Stanić, D.m. Dražić
    Abstract:

    Abstract The corrosion behavior and thermal stability of Epoxy Coating electrodeposited on aluminium have been investigated during exposure to 3% NaCl. Electrochemical impedance spectroscopy (EIS), gravimetric liquid sorption experiments, thermogravimetric analysis (TGA) and polarization measurements were used. From the results obtained from EIS (pore resistance, Coating capacitance, relative permittivity of Coating, charge-transfer resistance, double-layer capacitance), gravimetric liquid sorption experiments (diffusion coefficient, energy of activation of water diffusion) and TGA (water content inside the Coating and thermal stability), it can be concluded that the electrochemical, transport and thermal properties of an Epoxy Coating on aluminium are significantly improved with respect to the same Epoxy Coating on other substrates (steel, phosphatized steel, steel modified by Zn–Ni alloy). The better protective properties can be explained by less porous structure of the Coating on aluminium, caused by lower rate of H 2 evolution, while the prolonged corrosion protection is due to the passive, mainly barrier film of Al 2 O 3 on its surface.