Effect of the Acid Environment on the Electrochemical Behaviour of 1045 Steel Reinforced Cement

External corrosion is one of the most common causes of oilwell casing failure. Hostile environments can be due to acidizing treatments. Although it is common to add corrosion inhibitors and oxygen scavengers in acidic solutions to control external casing corrosion, their real efficiency is unknown yet. Therefore, it is important to establish how aggressive to steel are the different hostile environments to help decide which acidic systems can be used. A comparative evaluation of the corrosion of steel immersed in hardened cement slurries submitted to commonly acidizing agents is suggested. The performance of Special Class Portland Cement Slurries reinforced with polished SAE 1045 steel was evaluated by electrochemical measurements as a function of time. Open circuit potential, polarization curves and electrochemical impedance spectroscopy were studied. 15.0 wt% HCl, 12.0 wt% HCl + 3.0 wt% HF (regular mud acid), 10.0 wt% HAc + 1.5 wt% HF and a simulated hardened cement slurry pore solution were used as electrolytes. The most aggressive acid solution to plain Portland hardened cement slurries was the regular mud acid. 10.0 wt% HAc + 1.5 wt% HF electrolytes were the least aggressive ones, showing open circuit potentials around +250 mV compared to -130 mV of the simulated hardened cement slurry pore solution after the first 24 hours of immersion. This behavior was observed during two months at least. Similar corrosion rates were shown between both electrolytes, around 0.01 μA.cm-2. Total impedance values, insipient arcs and large polarization resistance capacitive arcs on the Nyquist plots, indicating passivity process, confirmed the behaviour of the system in the 10.0 wt% HAc + 1.5 wt% HF electrolyte.

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Comparison of the influence of nitrate ions on the electrochemical behaviour of iron and carbon steels in sulphate solutions

Journal of the Serbian Chemical Society ◽

10.2298/jsc0206425m ◽

2002 ◽

Vol 67 (6) ◽

pp. 425-436 ◽

Cited By ~ 3

Author(s):

Houy Ma ◽

Shenhao Chen ◽

Chao Yang ◽

Jingli Luo

Keyword(s):

Electrochemical Impedance ◽

Electrochemical Behaviour ◽

Low Frequency ◽

Open Circuit ◽

Carbon Steels ◽

General Corrosion ◽

Impedance Spectra ◽

Nitrate Ions ◽

Capacitive Loop ◽

Acidic Sulphate

The effect of nitrate ions on the electrochemical behaviour of iron (ferrite) and two carbon steels (martensite and pearlite) in sulphate solutions of different pH values was investigated by cyclic voltammetry polarization and electrochemical impedance spectroscopy. The pitting inhibiting effect of nitrate ions on ferrite in sulphate media is pH dependent. Nitrate ions were unable to inhibit the pitting on ferrite in neutral sulphate solutions, but did effectively protect passivated ferrite from pitting in acidic sulphate solutions. No pitting occurred on the surface of the martensite and pearlite specimens in sulphate solutions regardless of the pH of the solutions. At the open-circuit corrosion potentials, the three materials underwent general corrosion. The impedance spectra for the three materials measured in neutral sulphate solutions containing nitrates and chlorides at the corrosion potentials all showed a capacitive loop, while in acidic sulphate solutions their impedance spectra were greatly reduced in size and displayed at least a low frequency impedance loop (inductive or capacitive loop) besides the well-known high frequency capacitive loop. The variation of the impedance behaviour with pH is explained.

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Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

International Journal of Corrosion ◽

10.1155/2011/856415 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Irene Carrillo ◽

Benjamín Valdez ◽

Roumen Zlatev ◽

Margarita Stoycheva ◽

Michael Schorr ◽

...

Keyword(s):

Carbon Steel ◽

Reverse Osmosis ◽

Corrosion Inhibition ◽

Heat Exchangers ◽

Electrochemical Impedance ◽

Galvanic Corrosion ◽

Electrochemical Behaviour ◽

Open Circuit ◽

X Ray ◽

Galvanic Couple

The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS), exposed to reverse osmosis water (RO) used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS). The surface conditions were characterized by scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDS). The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

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Effect of Iron Content on Corrosion Properties of Pure Titanium as Grain Refiner

Materials ◽

10.3390/ma14237193 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7193

Author(s):

Bosung Seo ◽

Hyeon-Tae Im ◽

Ki-Beom Park ◽

Kwangsuk Park ◽

Hyung-Ki Park

Keyword(s):

Corrosion Resistance ◽

Open Circuit Potential ◽

Electrochemical Impedance ◽

Pure Titanium ◽

Open Circuit ◽

Tio2 Layer ◽

Grain Refiner ◽

Corrosion Properties ◽

Acid Environment ◽

Titanium Cathode

Microstructures and corrosion properties of pure titanium were characterized when iron was used as a grain refiner. The added Fe element acted as a strong grain refiner for pure titanium by forming β Ti phase at grain boundaries, and 0.15 wt% Fe was revealed to be a sufficient amount to make the grain size of pure titanium below 20 μm, which was the requirement for the desired titanium cathode. However, corrosion resistance was decreased with the Fe amount added. From the open circuit potential (OCP) results, it was obvious that the TiO2 stability against the reducing acid environment was deteriorated with the Fe amount, which seemed to be the main reason for the decreased corrosion resistance. Electrochemical impedance spectroscopy (EIS) results showed that both the decrease in the compact oxide film’s resistance (Rb) and the appearance of the outer porous film occurred as a result of the dissolution of the TiO2 layer, whose phenomena became more apparent as more Fe was added.

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Galvanic Corrosion Study between Tensile-Stressed and Non-Stressed Carbon Steels in Simulated Concrete Pore Solution

Metals ◽

10.3390/met12010098 ◽

2022 ◽

Vol 12 (1) ◽

pp. 98

Author(s):

Zheng Dong ◽

Chuanqing Fu ◽

Amir Poursaee

Keyword(s):

Charge Transfer ◽

Tensile Stress ◽

Electrochemical Impedance ◽

Pore Solution ◽

Charge Transfer Resistance ◽

Open Circuit ◽

Carbon Steels ◽

Cyclic Polarization ◽

Transfer Resistance ◽

Low Frequencies

The present study investigated the galvanic effect between tensile-stressed and non-stressed carbon steels, in addition to the influence of the tensile stress on the passivation and corrosion behavior of steel in a simulated concrete pore solution. Three different levels of tensile stress, ranging from elastic to plastic stress on the surface, were applied by adjusting the displacement of C-shape carbon steel rings. Different electrochemical measurements including the open circuit potential (OCP), the electrochemical impedance spectroscopy (EIS), the zero-resistance ammetry (ZRA), and the cyclic polarization were performed. Based on the results of EIS, the tensile stress degraded the resistance of the oxide film in moderate frequencies while enhancing the charge transfer resistance in low frequencies during passivation. As corrosion propagated, the stressed steel yielded a similar charge transfer resistance to or an even lower charge transfer resistance than the non-stressed steel, especially in the case of plastic tensile stress. The galvanic effect between the tensile-stressed and non-stressed steels increased the chloride threshold value of the tensile-stressed steel, although the susceptibility to pitting corrosion was exhibited after being corroded.

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An Electrochemical Impedance Spectroscopy Study of Al-Zn and Al-Zn-Sn Alloys in Tropical Seawater

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.510-511.284 ◽

2012 ◽

Vol 510-511 ◽

pp. 284-292

Author(s):

M.C. Isa ◽

Abdul Razak Daud ◽

M.Y. Ahmad ◽

M. Daud ◽

S.R. Shamsudin ◽

...

Keyword(s):

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Electrochemical Impedance ◽

Electrochemical Behaviour ◽

Low Frequency ◽

Passive Layer ◽

Open Circuit ◽

Surface Activation ◽

Impedance Spectroscopy Study ◽

Zn Alloy

In this paper, a study on the electrochemical behaviour and electrical properties of Al-Zn and Al-Zn-Sn alloys in tropical seawater using open circuit potential (OCP) measurement and electrochemical impedance spectroscopy (EIS) are reported. The results from both the OCP and EIS tests show that surface activation was observed in the Al-Zn alloy with the addition of 1.34 wt.% Sn which can be manifested by the shift of OCP values towards more electronegative direction. The EIS spectra of Al-Zn alloy exhibits a semicircle loop, while the EIS spectra for the Al-Zn-Sn alloy exhibits a semicircle with a semicircle inductive loop. The change in EIS spectra for Al-Zn-Sn alloy is correlated to the increase of surface activation resulting in a less stable passive layer. Equivalent circuits models were proposed to fit the impedance spectra and the corresponding electrical parameters with optimum values were deduced. The modulus impedance in the low frequency region or polarization resistance,Rpolobtained for the Al-Zn-Sn alloy,Rpol= 2.76 kΩ cm2) is slightly decreased compared to the corresponding value of the Al-Zn alloy,Rpol= 3.97 kΩ cm2), indicating a considerable reduction in the protective capability of the oxide layer on the Al-Zn-Sn alloy. It appears that the heterogeneous oxide film and pores formed on the Al-Zn-Sn alloy play a key role in reducing total resistance to the flow of electron at the alloy-electrolyte interface.

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The Effect of Sn on the Impedance Behaviour of Al-Zn Alloys in Natural Chloride Solution

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.442.322 ◽

2010 ◽

Vol 442 ◽

pp. 322-329 ◽

Cited By ~ 2

Author(s):

M.C. Isa ◽

M.Y. Ahmad ◽

Abdul Razak Daud ◽

M. Daud

Keyword(s):

Chloride Solution ◽

Electrochemical Impedance ◽

Electrochemical Behaviour ◽

Open Circuit ◽

Sem Images ◽

Active Dissolution ◽

Solution Interface ◽

Passive Current ◽

Zn Alloy ◽

Zn Alloys

Electrochemical behaviour of cast Al-Zn alloys in natural chloride solution were investigated by potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). Results from open circuit potential (OCP) measurement against immersion time showed a stable free corrosion process was achieved after 15 kiloseconds and alloys with more Sn contents had shifted OCP value towards more negative direction. Potentiodynamic polarisation curves showed that the corrosion potential (Ecorr) of aluminium alloys with Sn addition were much active compared to alloy without Sn. The anodic curves were characterized by no sign of passive current due active dissolution on the surface of the Al-Zn-Sn alloy. SEM images show that the presence of Sn in Al-Zn alloys produces better and uniform dissolution morphology. EIS results confirm that the presence of Sn is beneficial in improving anodic dissolution of Al-Zn alloys by reducing resistance to polarization (Rp). The presence of 0.1%wt. Sn in Al-Zn alloy has been found to be useful in activating electrochemical reaction at alloy-solution interface based on inductive loop in EIS diagram.

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Electrochemical Characterization and Inhibiting Mechanism on Calcium Leaching of Graphene Oxide Reinforced Cement Composites

Nanomaterials ◽

10.3390/nano9020288 ◽

2019 ◽

Vol 9 (2) ◽

pp. 288 ◽

Cited By ~ 3

Author(s):

Wu-Jian Long ◽

Tao-Hua Ye ◽

Li-Xiao Li ◽

Gan-Lin Feng

Keyword(s):

Graphene Oxide ◽

Loss Rate ◽

Electrochemical Impedance ◽

Pore Solution ◽

Strength Loss ◽

Hardened Cement ◽

Cement Composites ◽

Calcium Leaching ◽

Reinforced Cement ◽

Scanning Electron

Calcium leaching is a degradation progress inside hardened cement composites, where Ca2+ ions in cement pore solution can migrate into the aggressive solution. In this work, calcium leaching of graphene oxide (GO) reinforced cement composites was effectively characterized by combined techniques of electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Inhibiting mechanism of GO on calcium leaching of the composites was also examined. The obtained results show that the diameter of the semi-circle of the Nyquist curves of leached samples with GO addition decreased less than that of controlled samples. After leaching for 35 days, loss rate of model impedance RCCP of leached samples with 0, 0.05, 0.1, 0.15, and 0.2 wt.% GO addition was 94.85%, 84.07%, 79.66%, 75.34%, and 68.75%, respectively. Therefore, GO addition can significantly mitigate calcium leaching of cement composites, since it can absorb Ca2+ ions in cement pore solution, as well as improve the microstructure of the composites. In addition, coupling leaching depth and compressive strength loss were accurately predicted by using the impedance RCCP.

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A gateway for ion transport on gas bubbles pinned onto solids

Communications Chemistry ◽

10.1038/s42004-021-00481-7 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Veton Haziri ◽

Tu Pham Tran Nha ◽

Avni Berisha ◽

Jean-François Boily

Keyword(s):

Ion Transport ◽

Metal Ion ◽

Electrochemical Impedance ◽

Gas Bubbles ◽

Open Circuit ◽

Double Layers ◽

Water Geochemistry ◽

Chemical Potentials ◽

Pore Water Geochemistry ◽

Electric Potentials

AbstractGas bubbles grown on solids are more than simple vehicles for gas transport. They are charged particles with surfaces populated with exchangeable ions. We here unveil a gateway for alkali metal ion transport between oxygen bubbles and semi-conducting (iron oxide) and conducting (gold) surfaces. This gateway was identified by electrochemical impedance spectroscopy using an ultramicroelectrode in direct contact with bubbles pinned onto these solid surfaces. We show that this gateway is naturally present at open circuit potentials, and that negative electric potentials applied through the solid enhance ion transport. In contrast, positive potentials or contact with an insulator (polytetrafluoroethylene) attenuates transport. We propose that this gateway is generated by overlapping electric double layers of bubbles and surfaces of contrasting (electro)chemical potentials. Knowledge of this ion transfer phenomenon is essential for understanding electric shielding and reaction overpotential caused by bubbles on catalysts. This has especially important ramifications for predicting processes including mineral flotation, microfluidics, pore water geochemistry, and fuel cell technology.

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Strength Tests of Hardened Cement Slurries for Energy Piles, with the Addition of Graphite and Graphene, in Terms of Increasing the Heat Transfer Efficiency

Energies ◽

10.3390/en14041190 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1190

Author(s):

Tomasz Sliwa ◽

Aneta Sapińska-Śliwa ◽

Tomasz Wysogląd ◽

Tomasz Kowalski ◽

Izabela Konopka

Keyword(s):

Hardened Cement ◽

Environmental Aspects ◽

Cement Slurry ◽

Subsequent Increase ◽

Load Bearing ◽

Heat Transfer Efficiency ◽

Strength Tests ◽

Energy Piles ◽

New Buildings ◽

New Facility

The development of civilization, and subsequent increase in the number of new buildings, poses engineering problems which are progressively more difficult to solve, especially in the field of geotechnics and geoengineering. When designing new facilities, particular attention should be paid to environmental aspects, and thus any new facility should be a passive building, fully self-sufficient in energy. The use of load-bearing energy piles could be a solution. This article presents research on the cement slurry formulas with the addition of graphite and graphene, that can be used as a material for load-bearing piles. The proposed solution is to introduce U-tubes into the pile to exchange heat with the rock mass (the so-called energy piles). A comparison of four slurry formulas is presented: the first one consisting mainly of cement (CEM I), graphite, and water, and the remaining three with different percentages of graphene relative to the weight of dry cement. The results could contribute to the industrial application of those formulas in the future.

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Protection of Carbon Steel Rebars by Epoxy Coating with Smart Environmentally Friendly Microcapsules

Coatings ◽

10.3390/coatings11020113 ◽

2021 ◽

Vol 11 (2) ◽

pp. 113

Author(s):

Jacob Ress ◽

Ulises Martin ◽

Juan Bosch ◽

David M. Bastidas

Keyword(s):

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Corrosion Protection ◽

Corrosion Potential ◽

Electrochemical Impedance ◽

Pore Solution ◽

Control Sample ◽

Chloride Ions ◽

Epoxy Coating ◽

Transfer Resistance

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.

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