Microbiologically Induced Corrosion Monitoring Using Open-Circuit Potential (OCP) Measurements

2015 ◽  
Vol 227 ◽  
pp. 294-297 ◽  
Author(s):  
Rosilawati Mohd Rasol ◽  
Akrima Abu Bakar ◽  
Norhazilan Md Noor ◽  
Yahaya Nordin ◽  
Mardhiah Ismail
Keyword(s):  
Carbon Steel ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Control Sample ◽  
Desulfovibrio Desulfuricans ◽  
Open Circuit ◽  
Metal Loss ◽  
Desulfovibrio Vulgaris ◽  
Corrosion Monitoring ◽  
Microbiologically Induced Corrosion

This study investigates how sulfate-reducing bacteria (SRB) influence the process of microbiologically induced corrosion (MIC) of carbon steel by measuring corrosion potential using open-circuit potential (OCP) measurements. MIC is mainly influenced byDesulfovibrio vulgaris, formerly known asDesulfovibrio desulfuricans subsp. Desulfuricans, deposited asspirillum desulfuricans, which produces D(-)-lactate dehydrogenase. This strain was recommended by ATCC to be used in the tests described in ASTM. A pure colony of SRB was isolated from the Baram and Sungai Ular areas in Malaysia. An evaluation of SRB growth was performed during the test in the inoculated medium anaerobically at 37 ̊. The results showed that the corrosion potentialEocincreases in the presence of SRB in pure and mixed cultures as compared to the control sample. These results indicate that the SRB caused the metal loss on the carbon steel surface through direct corrosive action of the H2S generated by the bacteria during their metabolic process of reducing sulfates to the sulfide form.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

Experimental study of the mechanical and corrosion properties of ethyl silicate resin applied on low carbon steel

2021 ◽  
Vol 2 (108) ◽  
pp. 68-74
Author(s):  
M. Ali ◽  
J.H. Mohmmed ◽  
A.A. Zainulabdeen
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Open Circuit Potential ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Treatment Temperature ◽  
Ethyl Silicate ◽  
Low Carbon ◽  
Corrosion Properties ◽  
Mixture Ratio

Purpose: This work aimed at evaluating the properties of the ethyl silicate-based coating that can be applied on low carbon steel. Design/methodology/approach: Two mixture ratio types (2:1, and 3:2) of resin and hardener respectively were used to prepared two specimen models (A and B). Findings: It found that some mechanical properties (tensile, hardness, and impact strength) of ethyl silicate resin were evaluated according to standard criteria. Research limitations/implications: The effect of heat treatments at various temperatures (100, 150, and 200°C) and holding at different times (10, 20 & 30) min on hardness was investigated. Practical implications: Moreover, an open circuit potential corrosion test with a solution of 3.5% Sodium Chloride at room temperature and 60°C was used to determine the corrosion resistance of low carbon steel specimens coated with the two mixture types. Originality/value: The effects of mixture ratios (for resin and hardener) and heat treatment conditions on properties of ethyl silicate-based coating were studied. From obtained results, acceptable values of tensile, hardness, and toughness were recorded. Increasing heat treatment temperature and holding time leads to enhance hardness for both model types. An open circuit potential (OCP) tests show that there is an enhancement of protective properties of ethyl silicate coatings with mixture type B in comparison with type A was achieved. Generally, the results indicate that specimen model B has higher properties as compared with specimen model A.

scholarly journals The Effect of the Action of Impurities Present in Methanol as a Basis for Automobile Fuel and Their Impact on the Environment

2020 ◽  
Vol 70 (12) ◽  
pp. 4260-4265
Keyword(s):  
Air Pollution ◽  
Aluminum Alloy ◽  
Acid Chloride ◽  
Considerable Increase ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Open Circuit ◽  
Sulfur Oxides ◽  
Pitting Potential ◽  
Hydroxyl Ion

Corrosion of the tank made of aluminum alloy AlMg2,7Mn (5454) has been studied by electrochemical methods in methanolic solution containing different concentrations of acid, chloride, sulphate and water as impurities. In all these cases, the alloy exhibited a sponge passivity. Adding a 1mM solution in fuel leads to a considerable increase in corrosion potential, a 1 mM chlorine solution decreases the pitting potential, and a 1 mM solution of sulfate concentrations does not show any change. In the first phase, due to the hydroxyl ion that surrounds the aluminum, the present water leads to a decrease in the pitting potential.At the same time, the combustion of fuel remains the biggest source of air pollution. The air is polluted by impurities (acids, chlorides, sulphates and water) present in fuels, smoke (incomplete combustion) or nitrogen and sulfur oxides, so it is required to keep them within the limits set by the rules in force. Keywords: aluminium alloy, pitting potential, impurities, polarization curves, open circuit potential

scholarly journals Mechanical and Corrosion Properties of Mg-Based Alloys with Gd Addition

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1775 ◽  
Author(s):  
Aneta Kania ◽  
Ryszard Nowosielski ◽  
Agnieszka Gawlas-Mucha ◽  
Rafał Babilas
Keyword(s):  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Orthopedic Implants ◽  
Corrosion Current ◽  
Medical Application ◽  
Open Circuit ◽  
Dendritic Microstructure ◽  
Corrosion Properties ◽  
Electrochemical Parameters ◽  
Mechanical And Corrosion Properties

Magnesium alloys with rare earth metals are very attractive materials for medical application because of satisfactory mechanical properties. Nevertheless, low corrosion resistance is an obstacle in the use of Mg alloys as resorbable orthopedic implants. The paper presents results of mechanical and corrosion properties of MgCa5-xZn1Gdx (x = 1, 2, and 3 wt. %) alloys. Based on the microscopic observations it was stated that the studied alloys show a dendritic microstructure with interdendritic solute rich regions. The phase analysis reveals an occurrence of α-Mg and Mg2Ca, Ca2Mg6Zn3 phases that are thermodynamic predictions, and stated Mg26Zn59Gd7 phases in MgCa5-xZn1Gdx (x = 1, 2, and 3 wt. %) alloys. The Mg26Zn59Gd7 phases are visible as lamellar precipitations along interdendritic regions. It was confirmed that an increase of Gd content from 1 to 3 wt. % improves ultimate tensile (Rm; from 74 to 89 MPa) and compressive strength (Rc; from 184 to 221 MPa). Moreover, the studied alloys are active in Ringer’s solution. They are characterized by an increase of corrosion potential (Ecorr) of about 150 mV in comparison with values of open circuit potential (EOCP). The best electrochemical parameters (e.g., corrosion current density, icorr, polarization resistance, Rp, and Ecorr) were obtained for the MgCa3Zn1Gd2 alloy.

Conducting polyaniline/multi-wall carbon nanotubes composite paints on low carbon steel for corrosion protection: electrochemical investigations

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Pravin Deshpande ◽  
Sanket Vathare ◽  
Shashikant Vagge ◽  
Elena Tomšík ◽  
Jaroslav Stejskal
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Steel ◽  
Corrosion Protection ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Low Carbon ◽  
Multi Wall Carbon Nanotubes ◽  
Poly Aniline

AbstractThe coaxial coating of multi-wall carbon nanotubes (MWCNT) with poly(aniline) (PANI) was synthesised and a paint was prepared containing conducting PANI-MWCNT composite. The corrosion protection performance was assessed by open circuit potential measurements, potentiodynamic polarisation, and electrochemical impedance spectroscopy. The corrosion rate of low-carbon steel coated with 1.5 mass % of PANI-MWCNT-based paint in 3.5 mass % sodium chloride solution was found to be 0.037 mm y−1, about 5.2 times lower than that of unpainted low-carbon steel and 3.6 times lower than that of epoxy painted steel.

Effect of Different Dopants in Films TEOS/MPTS Used to Protect the Carbon Steel

2014 ◽  
Vol 805 ◽  
pp. 167-171 ◽  
Author(s):  
F.S. Silva ◽  
P.H. Suegama ◽  
W.P. Silva ◽  
A.W. Rinaldi ◽  
N.L.C. Domingues ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Open Circuit Potential ◽  
Hybrid Film ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
The Other ◽  
Nacl Solution ◽  
Hybrid Films ◽  
Impedance Measurements ◽  
Current Densities

Schiff bases m-toluene N-Salicylideneaniline (m-TOL), (B) m-nitro-N- Salicylideneaniline (m-NTR) and (C) m-methoxy-N-salicylideneaniline (m-MTX) and cerium ions were studied added to 3.5 wt.% NaCl solution and added to the hybrid film based tetraethoxysilane (TEOS) e 3-methacryloxypropyltrimethoxysilane (MPTS). The polarization measurements showed lower current densities for the steel in NaCl with m-MTX, indicating that the m-MTX may be acting as an inhibitor. The hybrid films were doped with the m-MTX, Ce (III) or Ce (IV). Electrochemical measurements of open circuit potential (EOC), polarization curves and electrochemical impedance spectroscopy (EIS), were used to evaluate the corrosion behavior of the hybrid films. According Electrochemical Impedance measurements, all hybrid films, provided protection to the carbon steel. The films doped with Ce (IV), provided greater protection than the other, which indicates that this is the most suitable dopant for use in films.

The formation process of Zr-doped silane film on carbon steel during immersing in Zr(NO3)4/silane mixed solutions

2017 ◽  
Vol 64 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Xiaochao Xian ◽  
Chenglong Nai ◽  
Lixin Li ◽  
Shuo Zhao
Keyword(s):  
Carbon Steel ◽  
Formation Process ◽  
Open Circuit Potential ◽  
Electrode System ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Self Healing ◽  
Content Type ◽  
Mixed Solutions ◽  
Zirconium Compounds

Purpose Immersion is one of the key steps during the preparation of silane-based hybrid films, which has important effects on the performance of films after curing. In this paper, the formation process of Zr-doped silane film (i.e. the adsorption of silane and deposition of zirconium compounds) on carbon steel immersed in Zr(NO3)4/silane mixed solutions was investigated. Design/methodology/approach The method of in situ monitoring the open circuit potential of a two-electrode system, consisting of carbon steel and saturated calomel electrode, was used. The effects of immersion conditions (i.e. the concentration of Zr(NO3)4 and pH of Zr(NO3)4/silane mixed solution) on the open circuit potential were investigated in detail. Furthermore, the surface coverage rate of different cured films (i.e. Zr cured film, silane cured film and Zr/silane composite cured film) after curing on carbon steel was calculated according to the results of polarization curves. Electrochemical impedance spectroscopy (EIS) was used to study the self-healing property of Zr-doped silane cured film. Findings The results indicate that in Zr(NO3)4/silane mixed solutions, most zirconium compounds deposit on the surface of carbon steel at the initial immersing stage, then the adsorption of silane on the residual surface of carbon steel dominates the following immersing stage. EIS results show that the Zr-doped cured film has improved self-healing property. Originality/value First, the method of in situ monitoring the open-circuit potential of two-electrode system was applied to investigate the deposition of Zr and the adsorption of silane on carbon steel immersed in Zr(NO3)4/silane mixed solutions. Second, the formation process of Zr-doped silane film was proposed.

scholarly journals Experimental evaluation of corrosion resistance of the alloys used in the fixed dental prosthesis

2015 ◽  
Vol 61 (2) ◽  
pp. 117-120
Author(s):  
Costin Coman ◽  
◽  
Raluca Monica Comăneanu ◽  
Violeta Hâncu ◽  
Horia Mihail Barbu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Applied Research ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Open Circuit ◽  
Metal Alloys ◽  
Fixed Dental Prosthesis

Objectives. In this study we evaluated corrosion resistance of three types of metal alloys (two NiCr and one CoCr). Methods. Samples (coded A, B, C) of circular shape, with dimensions 13 x 1.5 mm, sanded and polished, were introduced in Fusayama Meyer artificial saliva at pH 5.2 and 37 ± 0.5°C and tested in terms of corrosion resistance with a potentiostat/galvanostat (model 4000 PARSTAT, Princeton Applied Research). Results. Open circuit potential EOC [mV] ranged between 21.316 and 5.75. Corrosion potential Ecor [mV] was between -73.536 and -395.662, and the corrosion current density icor [A/cm2] was between 1.237 x 10-6 and 905.13 x 10-9. Conclusion. The best corrosion behavior in Fusayama Meyer artificial saliva at pH 5.2 and at a temperature of 37 ± 0.5°C is the alloy A, followed by the alloy C.

Corrosion study of low carbon steel under simulated geological disposal environments for HLW in China

2020 ◽  
Author(s):  
Junhua Dong
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Open Circuit Potential ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Low Carbon ◽  
Simulated Groundwater

<p>In the multi-barrier system of HLW repository, overpack is the first barrier to isolate high-level radioactive nuclides from biosphere, and Low carbon steel has been considered to be a promising candidate material for manufacturing the oberpack due to its good mechanical performance and workability and weldability. However, during thousands of years of geological disposal, the corrosion resistance of low carbon steel and its corrosion evolution behavior are the first element that must be fully understood, because it determines the life cycle of the artificial barrier.</p><p>Conventional studies had suggested that the corrosion of low carbon steel under the deep geological environment was driven by hydrogen evolution reaction (HER) based on that the dissolved oxygen was completely depleted during the long term disposal. However, the residual oxygen content is a critical factor to determine the corrosion mode of cathodic reduction reaction. Thermodynamics data indicated that the initial ferrous corrosion products formed in the deaerated bicarbonate solution can be chemically oxidized into ferric substance by the trace content of dissolved oxygen, and the accumulated FeOOH as a cathodic depolarizer significantly increased the open circuit potential and enhanced the corrosion rate of the low carbon steel. Moreover, chloride and sulfate in the simulated groundwater can reduce the increase of open circuit potential but it still promotes the corrosion of the low carbon steel. As the environments contained aggressive anions and high concentration of dissolved oxygen, low carbon steel was prone to suffer from the localized corrosion and the corrosion rate was obviously increased. By alloying with some contents of Ni and Cu, the corrosion rate of low alloy steel was decreased by an order of magnitude and it was less prone to suffer from the localized corrosion.</p><p>Under the conditions of simulated groundwater with different content of GMZ bentonite，the bentonite colloidal particle layer attached to the surface of low carbon steel showed blocking effect on resisting oxygen diffusion to the steel substrate, which consequently decrease the further oxidation of ferrous to ferric substances and the corrosion rate of low carbon steel. However, the barrier performance of bentonite colloids would be deteriorated due to their coagulation caused by the ferrous ions dissolved from the steel substrate. High content of bentonite was beneficial to maintain and to prolong the stabilization of the barrier system. An equivalent circuit model which correlates with the interfacial structure between electrode substrate and rust and bentonite layer was proposed. The fitting results showed a very good match between the model and experimental data, and the evolution of the results was also in agreement with real changes.</p>

Corrosion of Carbon Steel in Nanofluid Containing ZrO2 Nanoparticle at Different Temperature

2014 ◽  
Vol 896 ◽  
pp. 168-172 ◽  
Author(s):  
Djoko Hadi Prajitno ◽  
Dani Gustaman Syarief
Keyword(s):  
Carbon Steel ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positive Displacement ◽  
Steel Increase ◽  
Polarization Technique ◽  
Before And After ◽  
Increasing Temperature

Corrosion of carbon steel in nanofluid containing 0.1 gpl of ZrO2nanoparticle at temperature from 25 to 55°C was investigated by using potentiodynamic polarization techniques. The open circuit potential measurements, cathodic and anodic polarization were used to characterize the corrosion behavior of carbon steel. Metallurgical techniques such as optical microscopy and X-ray diffraction (XRD) were used to characterize the alloys before and after corrosion testing. The microstructures of the as received carbon steel exhibited equaxed morphology. While corrosion specimens showed that microstructure of carbon steel alloys relatively unchanged after polarization testing. X ray diffraction examination of carbon steel before polarization represent γ phase and after polarization is still γ phase with minor Fe2O3. The open circuit potentials of carbon steel increase to positive displacement with increasing temperature nanofluids. The results of polarization technique show that corrosion currents increase and therefore corrosion rates become faster with the increase of nanofluids temperature.

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