Evaluation of the corrosion protection of defective polyaniline/epoxy coating by localized electrochemical impedance spectroscopy

2015 ◽  
Vol 12 (4) ◽  
pp. 777-785 ◽  
Author(s):  
Yingjun Zhang ◽  
Yawei Shao ◽  
Guozhe Meng ◽  
Tao Zhang ◽  
Ping Li ◽  
...  
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.


Author(s):  
Nguyen Tuan Anh ◽  
Ngo Thi Hoa ◽  
To Thi Xuan Hang ◽  
Nguyen Thuy Duong ◽  
Trinh Anh Truc

Abstract: Zinc aluminum hydrotalcite containing 2-benzothiazolythio-succinic acid (HT-BTSA) and modified by 2-aminoethyl-3-aminopropyltrimethoxysilane (APS) at different concentrations (3%, 5% and 10%). APS modified HT-BTSA (HT-BTSA-S) was incorporated in epoxy coatings at 3% concentration. The corrosion protective performance of the epoxy coatings containing HT-BTSA-S were evaluated by electrochemical impedance spectroscopy, adhesion measurement.  The results showed that the presence of HT-BTSA-S improved protection performance of epoxy coating and the best protection was obtained with HT-BTSA modified with 5 % APS.  


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.


2012 ◽  
Vol 560-561 ◽  
pp. 947-951
Author(s):  
Jian Hou ◽  
Guang Zhu ◽  
Jing Kun Xu ◽  
Jun Tao Wang ◽  
Yao Huang

An epoxy paint containing PEDOT/PSS was described herein. The corrosion behavior of steel samples coated with the paint was investigated in seawater. For this purpose, electrochemical impedance spectroscopy was utilized and surface morphology of coatings after corrosion was observed using scanning electron microscope. It was found that the addition of small PEDOT/PSS to the epoxy resin increased its corrosion protection efficiency. Meanwhile, the possible mechanism was discussed.


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