Water-Based Polyaniline/Montmorillonite/Epoxy Composite Coatings for the Corrosion Protection of Mild Steel

2009 ◽  
Vol 79-82 ◽  
pp. 1067-1070
Author(s):  
Yu Feng Li ◽  
Xiao Hui Gao ◽  
Hong Lei Zhu ◽  
Liu Yang

Polystyrene sulfonic acid (PSSA) doped water-dispersible polyaniline (PANI) /montmorillonite (MMT) clay composites were firstly synthesized by intercalation polymerisation in aqueous medium and characterized by XRD and FT-IR. The results showed exfoliated silicate nanolayers of MMT clay dispersed in the PANI matrix and has interaction involving hydrogen bonding between the PSSA-PANI chain and the surface of the MMT clay layer. This composites is more thermal stable than that of without clay samples and results in good stable temperature-dependent dc conductivity [σdc(T)] as temperature changed. The composite anticorrosion coatings of PANI/MMT and waterborne epoxy resin emulsion (EP) were prepared by mixture in aqueous medium and used for corrosion protection of mild steel. Open circuit potential (OCP), Electrochemical impedance spectroscopy (EIS) and Tafel plot demonstrated that the PANI/MMT/EP composite coatings have better anticorrosion properties than PANI/EP, MMT/EP and PANI/MMT/EP mixture. It’s impedance and corrosion potential is higher and the corrosion current density is lower. The anticorrosion coatings are environmental friendly because of water dispersion medium. Introduction

2010 ◽  
Vol 152-153 ◽  
pp. 1890-1893
Author(s):  
Yu Feng Li ◽  
Liu Yang ◽  
Xiao Hui Gao ◽  
Zhao Po Zeng

Doped water-dispersible polyaniline (PANI) emulsion were synthesized by emulsion polymerization in aqueous medium and characterized by dc conductivity and Transmission electron microscope (TEM). The results showed the PANI has bar-like shape and the diameter is about 200nm. The composite anticorrosion coatings of PANI emulsion and waterborne epoxy resin emulsion (EP) were prepared by mixture in aqueous medium and used for corrosion protection of mild steel. Open circuit potential (OCP) and Electrochemical impedance spectroscopy (EIS) demonstrated that the PANI/EP composite coatings have better anticorrosion properties than EP. It’s impedance and corrosion potential is higher. Scanning electron microscope (SEM) and Energy dispersive spectrometer (EDS) showed that the oxidation film formed on the metal surface and prevent corrosion effectively. The anticorrosion coatings are environmental friendly because of water dispersion medium.


2012 ◽  
Vol 151 ◽  
pp. 323-326 ◽  
Author(s):  
Yu Feng Li ◽  
Zhao Po Zeng ◽  
Di Wang ◽  
Xi Ge Wu ◽  
Liang Sheng Qiang

Water-based Polyaniline(PANI) emulsion and Fluorocarbon(FC) emulsion were synthesized by emulsion polymerization method. The doped polyanline were characterized by Transmission electron microscope(TEM) and X-ray diffraction(XRD). The results showed the PANI has bar-like shape and local crystallinity. The composite anticorrosion coatings of PANI emulsion and FC emulsion were prepared by mixture in aqueous medium and used for corrosion protection of mild steel. The corrosion protection property of PANI/FC coatings on mild steel was investigated by electrochemical impedance spectroscopy(EIS) and open circuit potential(OCP) technique in 3.5wt%NaCl aqueous solution. The results indicated that the water-based PANI/FC coatings could offer high protection because the impedance values and corrosion potential remained at higher. Scanning electron microscope(SEM) showed that the oxidation film formed on the metal surface and prevent corrosion effectively due to the passive effect of PANI pigment. The anticorrosion coatings are environmental friendly because of water dispersion medium.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 903
Author(s):  
Florina Branzoi ◽  
Adriana Băran ◽  
Simona Petrescu

In this research, electrodeposition procedure was utilized for the synthesis of a new composite polymer: N-methylpyrrole–Triton–X100/N, N, N-diethylaniline (NMpy-TRx100/NNDEA) used as a coating on carbon steel type OL 37 electrode for corrosion protection. The surfactant Triton–X100, a dopant ion utilized throughout the process of electropolymerization, had a significant impact on the corrosion protection of this composite by impeding the penetration of corrosive ions. PNMpy-TRx100/PNNDEA coatings were successfully realized on the OL37 substrate by a galvanostatic method of synthesis using the solutions 0.1 M NNDEA, 0.1 M MPY, 0.03 M TRX-100, and 0.3 M H2C2O4, at varied current densities (3 mA/cm2, 5 mA/cm2 and 8 mA/cm2) in different molar ratios (1:1, 1:5, 3:2 and 5:1). The deposition was performed for 20 and 30 min. The polymeric composite coatings were characterized electrochemically, spectroscopically, and morphologically by cyclic voltammetry, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. Corrosion protection performance of PNMpy-TRx100/PNNDEA-coated OL 37 was examined through potentiostatic and potentiodynamic polarization, open circuit potential measurements, and electrochemical impedance spectroscopy procedures in 0.5 M H2SO4 media. The corrosion rate of PNPMpy-TRx100/PNNDEA-coated OL 37 was denoted to be around nine times less than that of an uncoated electrode. The corrosion protection yield of the coating was more than 90%. The best effectiveness was realized for PNMPY-TRX-100/PNNDEA by electrodeposition at 5 mA/cm2 current density applied in molar ratios of 5:1 and 3:2, and at 8 mA/cm2 current densities applied in molar ratio 5:1. The outcomes of the corrosion experiments revealed that PNMPY-TRX-100/PNNDEA coatings provide a good anticorrosion protection of OL 37 in corrosive solutions.


Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.


Corrosion inhibition of mild steel in 240 ppm NaCl solution using Calcium D-Pantothenate (Vitamin B5 ) as corrosion inhibitor is studied using electrochemical impedance, potentiodynamic polarization and weight loss studies. From the potentiodynamic polarization studies, icorr (corrosion current density) decreases with increasing the concentration of vitamin B5 (VB5 ). The CR (corrosion rate) decreases and the IE (inhibition efficiency) of VB5 increases on increasing the concentration of VB5 .Surface investigation using SEM, EDX spectra, UV-Vis, FTIR, electrochemical impedance, potentiodynamic polarization and adsorption isotherm parameter of VB5 in 240 ppm NaCl solution shows that VB5 can act asworthy corrosion inhibitors. Quantum chemical data obtained from density functional theory (DFT) calculations also agreed with the experimental outcomes.


2018 ◽  
Vol 65 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Mohd Rashid ◽  
Umesh S. Waware ◽  
Afidah A. Rahim ◽  
A.M.S. Hamouda

Purpose The purpose of this study is to compare the inhibitive effect of polyaniline (PAni) and N-cetyl-N,N,N trimethyl ammonium bromide (CTAB)-stabilized PAni in a hydrochloric acid (HCl) medium. Design/methodology/approach PAni has been deposited potentiodynamically on mild steel in the presence of CTAB as a stabilizing agent to achieve high corrosion inhibition performance by the polymer deposition. The corrosion inhibition studies of CTAB-stabilized PAni inhibitor in 0.1 M HCl acidic solution was carried out by electrochemical methods, namely, open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy technique. Findings The results of electrochemical studies have shown that the CTAB-stabilized PAni inhibitor has higher corrosion efficiency than PAni on mild steel in 0.1 M HCl solution. The maximum per cent efficiency evaluated using the potentiodynamic polarization method is approximately 91.9. Originality/value CTAB-stabilized PAni has never been studied as a corrosion inhibitor for mild steel in an acidic medium. The investigations demonstrate relatively the better corrosion inhibition efficiency and high dispersion of the polymer in the acidic medium.


Author(s):  
YeoHeung Yun ◽  
Zhongyun Dong ◽  
Dianer Yang ◽  
Vesselin Shanov ◽  
Zhigang Xu ◽  
...  

Corrosion and cell culture experiments were performed to evaluate magnesium (Mg) as a possible biodegradable implant material. The corrosion current and potential of a Mg disk were measured in different physiological solutions. The corrosion currents in cell culture media were found to be higher than in deionized water, which verifies that corrosion of Mg occurs faster in chloride solution. Weight loss, open-circuit potential, and electrochemical impedance spectroscopy measurements were also performed. The Mg specimens were also characterized using an environmental scanning electron microscope and energy-dispersive x-ray analysis (EDAX). The x-ray analysis showed that in the cell culture media a passive interfacial layer containing oxygen, chloride, phosphate, and potassium formed on the samples. U2OS cells were then co-cultured with a Mg specimen for up to one week. Based on visual observation, cell growth and function were not significantly altered by the presence of the corroding Mg sample. These initial results indicate that Mg may be suitable as a biodegradable implant material. Future work will develop small sensors to investigate interfacial biocompatibility of Mg implants.


2019 ◽  
Vol 37 (5) ◽  
pp. 657-678
Author(s):  
Muazzam Ghous Sohail ◽  
Mohammad Salih ◽  
Nasser Al Nuaimi ◽  
Ramazan Kahraman

Purpose The purpose of this paper is to present the results of a two-year long study carried out in order to evaluate the corrosion performance of mild steel bare bars (BB) and epoxy-coated rebar (ECR) in concrete under a simulated harsh environment of chlorides. Design/methodology/approach The blocks are subjected to Southern Exposure testing. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and Tafel plot are performed to measure the polarization resistance and corrosion current densities of these rebars. Knife-peel test was performed to assess the adhesion between epoxy and underlying steel after two years of exposure. Findings Mild steel BB showed a high corrosion current density of 1.24 µA/ cm2 in Tafel plots and a very low polarization resistance of 4.5 kΩ cm2 in LPR technique, whereas very high charge transfer resistance of 1672 and 1675 kΩ cm2 is observed on ECR and ECR with controlled damage (ECRCD), through EIS technique, respectively. EIS is observed to be a suitable tool to detect the defects in epoxy coatings. After two years of immersion in 3.89 percent NaCl− solution, the mild steel BB were severely corroded and a considerable weight loss was observed, whereas under heavy chloride attack, ECR showed no deterioration of epoxy coating and neither any corrosion of underlying steel. Results of this study show that the durability of reinforced concrete (RC) structures with respect to corrosion could be enhanced by using ECR, especially in harsh climatic conditions. Originality/value The corrosion performance of mild steel and ECR in concrete under a simulating splash zone environment is evaluated. EIS was used to evaluate the health of epoxy and corrosion state of underneath steel rebars. EIS was able to detect the defects in epoxy. The durability of RC structures could be enhanced in harsh climate regions by using ECR.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohd Rashid ◽  
Suhail Sabir ◽  
Afidah A. Rahim ◽  
Umesh Waware

The corrosion protective performance of polyaniline/palm oil (PAni-PO) blend coated on mild steel in 3% NaCl aqueous solutions has been evaluated by electrochemical methods, namely, open circuit potential (ocp), potentiodynamic polarization, and EIS spectroscopy. The surface of mild steel was covered by a dark green protective layer due to the physical interaction between the coating and steel. The permanent shifts of ocp and potentiodynamic polarization towards higher positive value of oxidation potential by about 800 mV and by a decrease in corrosion current density by sixfold in magnitude and an increase of 10 orders of magnitude in charge transfer resistance are due to protective coating.


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