Correlation between electrochemical impedance and current distribution of carbon steel under organic coating

2011 ◽  
pp. n/a-n/a ◽  
Author(s):  
D. Kong ◽  
Y. Wang ◽  
W. Zhang ◽  
W. Wang ◽  
X. Liu ◽  
...  
2021 ◽  
Vol 882 (1) ◽  
pp. 012063
Author(s):  
Ahmad Fauzi ◽  
Ahmad Zakiyuddin

Abstract The presence of chalcopyrite increases the corrosion rate of carbon steel through a galvanic couple. In this study, five organic coating systems were evaluated for their strength against consequent corrosion in the presence of copper concentrate by electrochemistry impedance spectroscopy (EIS) measurement. The coating system studied are a single application epoxy coating (C1); a three-layer epoxy system with zinc-rich epoxy primer base coat, surface tolerant epoxy middle layer, and a top layer polyurethane (C2); a three-layer epoxy system that has the advantages of fast dry time consist of epoxy zinc phosphate base coat primer, the middle layer of the epoxy primer containing the pigment zinc phosphate and top layer polyurethane (C3); metallic pigmented polyurethane coating (C4), and an epoxy coating which can be applied to wet surfaces or in water (C5). All those systems have been tested by the EIS. The test results showed that C2, C3, C4, and C5 coating systems maintained good barrier properties during the immersion process, the low frequency |Z| is more than 108Ω.cm2 after 30 days of immersion exposure. Epoxy modified coating (C1) had the lowest impedance with resistance under 106 Ω.cm2 provide poor corrosion protection.


2013 ◽  
Vol 313-314 ◽  
pp. 249-253 ◽  
Author(s):  
Jie Liu ◽  
Bin Wang ◽  
Lei Zhu ◽  
Tian Yuan Luo ◽  
Wei Wang

The potential distribution of carbon steel under epoxy coating exposed to natural seawater was investigated by the wire beam electrode (WBE) technique. The electrochemical impedance spectroscopy (EIS) of the WBE was characterized to analyze the behaviour of the coating degradation and metal corrosion at coating/metal interface. The mechanism of coating degradation was discussed from a point of electrochemical distribution. This research showed that the potential distribution had a close relationship with the characteristic of EIS in local area. The combined method can help us better understand the mechanism of the organic coating degradation and beneath substrate corrosion.


2020 ◽  
Vol 117 (6) ◽  
pp. 610
Author(s):  
Nadia Hammouda ◽  
Kamel Belmokre

Organic coatings are widely employed in the corrosion protection of most metal surfaces, particularly steel. They provide a barrier against corrosive species present in the environment, due to their high resistance to oxygen, water and ions transport. This study focuses on the evaluation of corrosion protection performance of epoxy paint on the carbon steel surface in chloride environment (3% NaCl) by Electrochemical Impedance Spectroscopy (EIS). The electrochemical behavior of painted surface was estimated by EIS parameters that contained paint film resistance, paint film capacitance and double layer capacitance. On the basis of calculation using EIS spectrums it was observed that pore resistance (Rpore) decreased with the appearance of doubled layer capacitance (Cdl) due to the electrolyte penetration through the film. This was further confirmed by the decrease of diffusion resistance (Rd) which was also the indicator of the deterioration of paint film protectiveness. Microscopic analyses have shown that oxidation dominates the corroded surfaces.


2019 ◽  
Vol 24 (4) ◽  
pp. 51-58
Author(s):  
Le Hong Quan ◽  
Nguyen Van Chi ◽  
Mai Van Minh ◽  
Nong Quoc Quang ◽  
Dong Van Kien

The study examines the electrochemical properties of a coating based on water sodium silicate and pure zinc dust (ZSC, working title - TTL-VN) using the Electrochemical Impedance Spectra (EIS) with AutoLAB PGSTAT204N. The system consists of three electrodes: Ag/AgCl (SCE) reference electrode in 3 M solution of KCl, auxiliary electrode Pt (8x8 mm) and working electrodes (carbon steel with surface treatment up to Sa 2.5) for determination of corrosion potential (Ecorr) and calculation of equivalent electric circuits used for explanation of impedance measurement results. It was shown that electrochemical method is effective for study of corrosion characteristics of ZSC on steel. We proposed an interpretation of the deterioration over time of the ability of zinc particles in paint to provide cathodic protection for carbon steel. The results show that the value of Ecorr is between -0,9 and -1,1 V / SCE for ten days of diving. This means that there is an electrical contact between the zinc particles, which provides good cathodic protection for the steel substrate and most of the zinc particles were involved in the osmosis process. The good characteristics of the TTL-VN coating during immersion in a 3,5% NaCl solution can also be explained by the preservation of corrosive zinc products in the coating, which allows the creation of random barrier properties.


Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 135
Author(s):  
Aurelia Visa ◽  
Nicoleta Plesu ◽  
Bianca Maranescu ◽  
Gheorghe Ilia ◽  
Ana Borota ◽  
...  

The inhibition effect of N,N′-phosphonomethylglycine (PMG) and vinyl phosphonic acid (VPA) on the 3% NaCl acidic solution corrosion of carbon steel iron was studied at different immersion times by potentiodynamic polarization, electrochemical impedance spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and computational methods. It is found from the polarization studies that PMG and VPA behave as mixed-type inhibitors in NaCl. Values of charge transfer resistance (Rct) and double layer capacitance (Cdl) in the absence and presence of inhibitors are determined. The PMG and VPA inhibitors were capable of inhibiting the corrosion process up to ≈91% and ≈85%, respectively. In the presence of PMG, the synergic effect of chlorine ions was observed. Density functional theory (DFT) was engaged to establish the adsorption site of PMG, VPA, and their deprotonated states. For studied compounds, the resulted values of ELUMO, EHOMO, energy gap (∆E), dipole moment (μ), electronic hardness (η), global softness (σ), electrophilic index (ω), and the electronic potential map are in concordance with the experimental data results regarding their corrosion inhibition behavior and adsorption on the metal surface.


2013 ◽  
Vol 781-784 ◽  
pp. 299-303
Author(s):  
Shu Lan Cai ◽  
Kang Quan Qiao ◽  
Fa Mei Feng

A new corrosion inhibior N,N-diethylammonium O,O-di (p-chlorophenyl) dithiophosphate (EDPDP) has been synthesized and its inhibition effect towards the corrosion of carbon steel in 1.0 molL-1 HCl solution at 25 °C has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The obtained results show that EDPDP is a excellent inhibitor and the inhibition efficiencies exceed 90 %. The polarization measurements reveal that EDPDP is a mixed type inhibitor and the equivalent circuit model of the corrosion inhibition process is obtained by the analysis of EIS data.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Gamal A. El Mahdy ◽  
Ayman M. Atta ◽  
Amro K. F. Dyab ◽  
Hamad A. Al-Lohedan

New method was used to prepare magnetite nanoparticle based on reduction of Fe(III) ions with potassium iodide to produce Fe3O4nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been developed for the first time. The polymer was crosslinked in the presence of N,N-methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as redox initiator system. The structure and morphology of the magnetic nanogel were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations. The results showed that the nanogel particles act as mixed inhibitors. EIS data revealed thatRctincreases with increasing inhibitor concentration.


2019 ◽  
Vol 66 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Walid Belmaghraoui ◽  
Aimad Mazkour ◽  
Hicham Harhar ◽  
Mourad Harir ◽  
Souad El Hajjaji

Purpose This study aims to investigate the corrosion inhibition effect of extracted oil from Ziziphus lotus fruit on corrosion of C38 carbon steel in 5.5 M H3PO4 solution using potentiodynamic polarization and impedance techniques. Design/methodology/approach Oil composition was determined using gas chromatography, and the results showed that oleic and palmitic acids present approximately 84.0 per cent of its total chemical content. Electrochemical impedance spectroscopy (EIS) data were analyzed by adapting it to a well-developed electric circuit model. The inhibition efficiency of Z. lotus oil was calculated and compared using Tafel polarization and EIS. Findings Accordingly, the oil extract was found to act as an anodic type inhibitor. Furthermore, inhibition efficiency of Z. lotus oil extract increase with oil concentrations and achieve approximately 70.5 per cent at 3 g/L solution of Z. lotus oil. Originality/value The results obtained from different tested methods were in line, and the oil was able to reduce significantly the kinetics of the corrosion process of C38 carbon steel.


2015 ◽  
Vol 63 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Wilfrido Martinez-Molina ◽  
Andres Torres-Acosta ◽  
Rosalba Hernández-Leos ◽  
Elia Alonso-Guzman ◽  
Itzel Mendoza-Pérez ◽  
...  

Purpose – The purpose of this paper is to determine if a type of cactus mucilage, Opuntia ficus-indica (OFI), may act as a corrosion inhibitor for carbon steel in cement-based materials (mortar) exposed to chloride-laden environment. Design/methodology/approach – Mortar prisms, reinforced with carbon steel rods, were immersed in sodium chloride (NaCl) solution for five wet – dry cycles. The experimentation included electrochemical monitoring (corrosion potential, Ecorr, and polarization resistance, Rp) of carbon steel during the time of exposure until corrosion-induced cracking appeared at the mortar surface. Crack survey on the mortar prisms was performed. Carbon steel rods were retrieved from the mortar after crack survey and steel mass loss at the end of the experimental period was estimated. A comparison between the different mixtures was also performed. Findings – OFI mucilage did perform as a corrosion inhibitor of steel in chloride contaminated mortar. Research limitations/implications – The experimental program needs to be corroborated in concrete specimens with typical dimensions. The surface oxide/hydroxide formation of the carbon steel in contact with the OFI mucilage is still unknown; thus, electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) analyses are needed. Practical implications – OFI mucilage is a suitable natural product that can be used to increase durability of concrete structures not only in countries where OFI cactus is produced, but also in many other countries where this plant is considered a plague. Originality/value – The new information obtained from this paper is the innovative use of a by-product of this cactus plant for construction industry applications.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1578 ◽  
Author(s):  
Haijuan Yang ◽  
Qiufeng Mo ◽  
Weizhou Li ◽  
Fengmei Gu

An organic coating is commonly used to protect metal from corrosion, but it is prone to failure due to microcracks generated by internal stress and external mechanical action. The self-healing and self-lubricating achieved in the coating is novel, which allows an extension of life by providing resistance to damage and repair after damage. In this study, a new approach to microencapsulating bifunctional linseed oil with polyurethane shell by interfacial polymerization. Moreover, the self-healing and self-lubricating coatings with different concentrations of microcapsules were developed. The well-dispersed microcapsules showed a regular spherical morphology with an average diameter of ~64.9 μm and a core content of 74.0 wt.%. The results of the salt spray test demonstrated that coatings containing microcapsules still possess anticorrosion, which is improved with the increase of microcapsules content, after being scratched. The results of electrochemical impedance spectroscopy showed a |Z|f=0.01Hz value of 104 Ω·cm2 for pure epoxy coating after being immersed for 3 days, whereas the coating with 20 wt.% microcapsules was the highest, 1010 Ω·cm2. The results of friction wear showed that the tribological performance of the coating was enhanced greatly as microcapsule concentration reached 10 wt.% or more, which showed a 86.8% or more reduction in the friction coefficient compared to the pure epoxy coating. These results indicated that the coatings containing microcapsules exhibited excellent self-healing and self-lubricating properties, which are positively correlated with microcapsules content.


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