Technical Inspection Engineering
Zeinab Nassaj; Fatemeh Ravari; Iman Danaee
Abstract
In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and used as anticorrosive pigments in epoxy nanocomposite coatings. The synthesized nanoparticle was characterized by FTIR, XRD, SEM, and EDX analyses. Graphene oxide decorated with CeO2 nanoparticles was dispersed ...
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In this paper, graphene oxide decorated with cerium oxide (CeO2) nanoparticles was prepared and used as anticorrosive pigments in epoxy nanocomposite coatings. The synthesized nanoparticle was characterized by FTIR, XRD, SEM, and EDX analyses. Graphene oxide decorated with CeO2 nanoparticles was dispersed in epoxy resin by sonication. The optimum nanoparticle content of the epoxy resin was studied by differential scanning calorimetry. The anticorrosive properties of these coatings were investigated using electrochemical impedance spectroscopy method and polarization in corrosive solution. Impedance parameters showed a decrease in the coating resistance over immersion time. The results indicated that the epoxy coatings containing nanoparticles could significantly increase the corrosion resistance of composite coatings compared to those of pure epoxy, and the highest value was obtained for 1% nanocomposite coatings after 270 days of immersion. Pull-off adhesion test showed that the highest value of adhesion was related to the coating containing 1% nanoparticles.
Petroleum Engineering
Hojatallah Koraee; Hadi Eskandari; Iman Danaee
Abstract
Corrosion results in hazardous and expensive damage to pipelines, vehicles, water and wastewater systems, and even home appliances. One of the most extensively practical methods for protecting metals and alloys against corrosion is to use organic inhibitors. The inhibition capability of 2-Mercaptobenzothiazole ...
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Corrosion results in hazardous and expensive damage to pipelines, vehicles, water and wastewater systems, and even home appliances. One of the most extensively practical methods for protecting metals and alloys against corrosion is to use organic inhibitors. The inhibition capability of 2-Mercaptobenzothiazole (2-MBT) against the corrosion of carbon steel in a 2 M NaCl solution was examined by Tafel polarization. By using 2-Mercaptobenzothiazole both the cathodic and anodic reactions are delayed through chemical and physical adsorption and blocking the active corrosion sites. Based on the polarization curves, it was indicated that by increasing the inhibitor concentration, the inhibition efficiency increases up to 70% at room temperature, and it improves at higher temperatures. The adsorption of 2-Mercaptobenzothiazole was based on the Langmuir adsorption isotherm. The enthalpies of activation were determined to be around +50 kJ.mol-1. The endothermic nature of the steel dissolution procedure is reflected by the positive symbols of the enthalpies (ΔH) of activation process. The determined values range from -32.69 to -35.81 kJ.mol-1, which shows both electrostatic adsorption and the chemisorption of the adsorption mechanism. The calculated entropy of adsorption was 78 J.mol-1.K-1 indicating the increment in the solvent entropy and a more positive water desorption entropy.
Chemical Engineering
Farhad Asgharyan; Mohammadreza Khosravi Nikou; Bagher Anvaripour; Iman Danaee
Abstract
The present study is about the reduction of humic acids (HA) by electrocoagulation (EC) method. Undesirable color, odor, taste, reacting with chlorine to produce toxic materials in water, and making a complex with heavy metal ions are some unfavorable environmental consequences of HA. Platinum and graphite ...
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The present study is about the reduction of humic acids (HA) by electrocoagulation (EC) method. Undesirable color, odor, taste, reacting with chlorine to produce toxic materials in water, and making a complex with heavy metal ions are some unfavorable environmental consequences of HA. Platinum and graphite as anode electrodes and platinum, titanium, and aluminum as cathode electrodes were used for this purpose. Also, solutions consisting of sodium sulfate (Na2SO4), as the electrolyte support, and humic acids at a concentration of 30 mg.l-1 were used in the reduction tests. We investigated the best condition for pollutant removal at pH values of 3, 5, and 7 and voltages of 5, 10, and 18. The samples were taken during the electrolysis and were analyzed by the pH meter and UV-visible spectrophotometer. Moreover, the oxidation phenomena on anodes surface were studied by cyclic voltammetry tests. The results confirm that the Gr/Al electrodes by coagulation phenomena shows the best performance in the elimination of HA at an electrolyte support concentration of 0.02 molar after approximately 23 min at a pH of 7 and a voltage equal to 10 V.
Mohammadreza Shishesaz; Davood Jafari; davood zaarei; Iman Danaee
Abstract
Different amounts of nanoclay were incorporated into the acrylic resin matrix at 0, 1, 3, and 5 wt.% loadings. The coatings were applied on low carbon steel plates. Optical microscopy, sedimentation test, transmission electron microscopy, and X-ray diffraction were employed to investigate the dispersion ...
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Different amounts of nanoclay were incorporated into the acrylic resin matrix at 0, 1, 3, and 5 wt.% loadings. The coatings were applied on low carbon steel plates. Optical microscopy, sedimentation test, transmission electron microscopy, and X-ray diffraction were employed to investigate the dispersion of nanoclay in matrix. The corrosion resistance of coatings was evaluated by electrochemical impedance spectroscopy, polarization measurement, and salt spray test. In addition, pull-off and cross-cut tests were used for the assessment of coating adhesion to the substrate. The results indicated that the anti-corrosive properties of the acrylic resin were obviously increased by the addition of nanoclay. The nanocomposite coatings containing 3 wt.% clay showed the best corrosion resistance. Finally, the nanocomposites containing 1 and 3 wt.% showed the highest adhesion to the substrate.
Niloufar Bahramipanah; Iman Danaee; Maryam Kanani; Mohammad Hosein Maddahy
Abstract
As an alternative to chromate conversion coatings, rare-earth coatings especially cerium, because of the low toxicity, have attracted considerable attention. Using dip immersion method, cerium-based conversion coating was deposited on aluminum 2024. Corrosion resistance was studied in 3.5 wt.% NaCl solution ...
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As an alternative to chromate conversion coatings, rare-earth coatings especially cerium, because of the low toxicity, have attracted considerable attention. Using dip immersion method, cerium-based conversion coating was deposited on aluminum 2024. Corrosion resistance was studied in 3.5 wt.% NaCl solution using potentiodynamic polarization, electrochemical impedance spectroscopy, and surface methods. The coated samples revealed a considerable decrease in corrosion rate and with increasing immersion time up to 1200 s, the coating resistance increased. Electrochemical impedance data showed that the aluminum charge transfer resistance was increased in the existence of cerium oxide conversion coatings. Using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), the chemical composition and surface morphology were also evaluated.
Hamid Reza Zamanizadeh; Mohammad Reza Shishesaz; Iman Danaee; Davood Zaarei
Abstract
In this study, the corrosion resistance of a bituminous coating reinforced with different ratios of nanoclay pigment was studied. To make nanocomposite coatings, 2, 3, and 4 wt.% of clay (Cloisite Na+) were incorporated into water emulsified bitumen. The coatings were applied to steel 37. Optical microscopy ...
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In this study, the corrosion resistance of a bituminous coating reinforced with different ratios of nanoclay pigment was studied. To make nanocomposite coatings, 2, 3, and 4 wt.% of clay (Cloisite Na+) were incorporated into water emulsified bitumen. The coatings were applied to steel 37. Optical microscopy and X-ray diffraction (XRD) were used to characterize the nanocomposite structure. In order to investigate the anticorrosion behavior of the coatings, electrochemical impedance spectroscopy (EIS) and direct current polarization techniques were used. The results show that the coatings containing nanoclay have better performance compared to the neat bitumen. Moreover, it was revealed that the corrosion resistance of the nanocomposite increased as the clay loading increased up to 4 wt.%.
