scholarly journals Electrochemical Impedance Spectroscopy Evaluation of Corrosion Protection of X65 Carbon Steel by Halloysite Nanotube-Filled Epoxy Composite Coatings in 3.5% NaCl Solution

Author(s):  
Duo Zhang ◽  
2013 ◽  
Vol 652-654 ◽  
pp. 1432-1435
Author(s):  
Qian Hu ◽  
Jing Liu ◽  
Jie Zhang ◽  
Feng Huang ◽  
Xing Peng Guo

The crevice corrosion behaviors of X52 carbon steel in two typical Cl--containing solutions were investigated by electrochemical noise and electrochemical impedance spectroscopy. Results show that oxygen concentration difference leads to the coupled current in NaCl + NaHCO3 solution while HAc concentration difference causes the coupled current in NaCl solution saturated with CO2 in the presence of HAc. There exists an apparent incubation stage during the crevice corrosion process of X52 carbon steel in the former. However, no obvious incubation period of crevice corrosion can be observed in the latter. Micrography shows that the crevice corrosion occurs indeed and the corrosion inside the crevice is not uniform.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
M. Casales-Diaz ◽  
L. M. Rivera-Grau ◽  
D. M. Ortega-Toledo ◽  
J. A. Ascencio-Gutierrez ◽  
...  

In order to determine the diesel contribution in the coadsorption process of the oil-soluble inhibitors, electrochemical impedance spectroscopy measurements have been carried out to study the performance of oil-soluble inhibitors in both presence and absence of diesel and CO2. The results showed that the presence of the oil phase provides some protection to the steel because the water-soluble fractions are capable of being adsorbed on the steel surface thereby reducing the corrosion rate. The oily phase does not contribute to the adsorption process of the inhibitor because the inhibitor is absorbed into the water-soluble fractions. The oil-soluble inhibitors are effective only when the solution is saturated with CO2. CO2saturation causes a decrease in the pH of the solution causing both an increase of the inhibitor solubility and a better dispersion of the inhibitor into the electrolyte.


Author(s):  
Mahboobeh Azadi ◽  
Hossein Tavakolli ◽  
Saeid Haghighatkhah ◽  
Freshteh Amjadi Eranegh

In this paper, various Ni-P composite coatings containing toner, MoS2, and nano-SiO2 particles were deposited on steel substrates by the electroless method. Then, the electrochemical properties of these coatings after a heat treatment process were compared. The microstructural evaluations were also done by using the optical and electron microscopy methods. Both Tafel polarization and electrochemical impedance spectroscopy techniques were utilized to survey the electrochemical behavior of such coatings. The surface morphology of all coatings contained cauliflower-like nodules. The X-ray diffraction patterns showed the crystalline phases of Ni and Ni3P for all coatings after the heat-treatment step. Obtained results showed that all composite coatings exhibited lower corrosion rates with respect to Ni-P coatings. Such a reduction was about 21.6-92.2%. This behavior was attributed to the presence of reinforcement as barriers for corrosive ion diffusion through the coating plus the changes in detected phases and thickness. Electrochemical impedance spectroscopy test results also demonstrated that the increase in the polarization resistance for composites coatings was about 18.4-85.3% after 1 h immersion in a 0.6M NaCl solution; however, when the immersion time increased to 24 h, such increased resistance changed to 18.1 to 73.1%. Totally, despite the lower deposition rate, the presence of MoS2 and nano-SiO2 particles were more effective than toner particles to raise the corrosion rate of the Ni-P coating.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 113
Author(s):  
Jacob Ress ◽  
Ulises Martin ◽  
Juan Bosch ◽  
David M. Bastidas

The protection of mild steel by modified epoxy coating containing colophony microencapsulated corrosion inhibitors was investigated in this study. The corrosion behavior of these epoxy coatings containing colophony microcapsules was studied by electrochemical analysis using cyclic potentiodynamic polarization and electrochemical impedance spectroscopy. The microcapsule coating showed decreased corrosion current densities of 2.75 × 10−8 and 3.21 × 10−8 A/cm2 along with corrosion potential values of 0.349 and 0.392 VSCE for simulated concrete pore solution and deionized water with 3.5 wt.% NaCl, respectively, indicating improved corrosion protection in both alkaline and neutral pH. Electrochemical impedance spectroscopy analysis also showed charge transfer resistance values over one order of magnitude higher than the control sample, corroborating the electrochemical corrosion potential and current density testing results. Overall, the use of colophony microcapsules showed improved corrosion protection in simulated concrete pore solution and DI water solutions containing chloride ions.


2015 ◽  
Vol 227 ◽  
pp. 515-518 ◽  
Author(s):  
Luigi Calabrese ◽  
Lucio Bonaccorsi ◽  
Chiara Borsellino ◽  
Angela Caprì ◽  
Francesca Fabiano ◽  
...  

In this work the assessment of the corrosion performances in saliva solution of NdFeB magnets coated with silane layers was studied for its application in orthodontic brackets. The silane film, deposited by dip coating technique, has been prepared with varying dipping steps, with the purpose to identify the number of layers able to achieve an optimal protective action. Corrosion protection performance, during immersion in Fusayama synthetic saliva solution, was evaluated by means electrochemical impedance spectroscopy (EIS). The silane coatings evidenced good barrier properties resulting in an improvement of the anti-corrosion performances of the magnets. Better results were observed for samples with at least 15 layers of silane, that evidenced still acceptable protective action after three days of immersion in a Fusayama synthetic saliva solution.


2017 ◽  
Vol 24 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Murat Ates

AbstractMethylcarbazole (MCz) and its nanocomposites with Montmorillonite nanoclay and Zn nanoparticles were chemically synthesized on a stainless steel (SS304) electrode. The modified electrode was characterized by optical microscope, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier-transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR), four-point probe, and electrochemical impedance spectroscopy (EIS) analysis. The synthesized stainless steel/poly(methylcarbazole) (SS/P(MCz)), stainless steel/poly(methylcarbazole)/nanoclay (SS/P(MCz)/nanoclay), and stainless steel/poly(methylcarbazole)/nanoZn (SS/P(MCz)/nanoZn) were studied by potentiodynamic polarization curves. The protective behavior of these coatings in 3.5% NaCl as the corrosion medium was investigated using Tafel polarization curves, as well as electrochemical impedance spectroscopy. The corrosion protection parameters were also supported by EIS and an equivalent circuit model of Rs(Qc(Rc(QpRct))). The corrosion current of the SS/P(MCz)/nanoclay samples was found to be much lower (icorr=0.010 μA×cm-2) than that of SS/P(MCz)/nanoZn (icorr=0.031 μA×cm-2) and pure SS/P(MCz) samples. These results reveal that chemically synthesized SS/P(MCz), SS/P(MCz)/nanoclay, and SS/P(MCz)/nanoZn nanocomposite film coating have high corrosion protection efficiency (PE=99.56%, 99.89%, and 99.67%, respectively). Thus, based on the study findings, we posit that nanoclay and Zn nanoparticles possess favorable barrier properties, which can be employed in order to achieve improvements in chemical corrosion protection through P(MCz) coating.


2019 ◽  
Vol 43 (16) ◽  
pp. 6303-6313 ◽  
Author(s):  
Ambrish Singh ◽  
K. R. Ansari ◽  
M. A. Quraishi ◽  
Savas Kaya ◽  
Priyabrata Banerjee

The corrosion inhibition behavior of a naphthoxazinone derivative 1-phenyl-1,2-dihydronaphtho[1,2-e][1,3]oxazin-3-one (PNO) on J55 steel in 3.5 wt% NaCl solution saturated with carbon dioxide was evaluated using weight loss, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization.


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