Influence of soil moisture on the residual corrosion rates of buried carbon steel structures under cathodic protection

2015 ◽  
Vol 176 ◽  
pp. 1410-1419 ◽  
Author(s):  
D. Nguyen Dang ◽  
L. Lanarde ◽  
M. Jeannin ◽  
R. Sabot ◽  
Ph. Refait
Keyword(s):  
Soil Moisture ◽  
Carbon Steel ◽  
Cathodic Protection ◽  
Steel Structures ◽  
Corrosion Rates

scholarly journals AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2158
Author(s):  
Andrea Brenna ◽  
Silvia Beretta ◽  
Marco Ormellese
Keyword(s):  
Carbon Steel ◽  
Cathodic Protection ◽  
Grey Literature ◽  
Reference Electrode ◽  
Steel Structures ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Narrative Literature Review ◽  
Protection Potential ◽  
Ac Interference

Cathodic protection (CP), in combination with an insulating coating, is a preventative system to control corrosion of buried carbon steel pipes. The corrosion protection of coating defects is achieved by means of a cathodic polarization below the protection potential, namely −0.85 V vs. CSE (CSE, copper-copper sulfate reference electrode) for carbon steel in aerated soil. The presence of alternating current (AC) interference, induced by high-voltage power lines (HVPL) or AC-electrified railways, may represent a corrosion threat for coated carbon steel structures, although the potential protection criterion is matched. Nowadays, the protection criteria in the presence of AC, as well as AC corrosion mechanisms in CP condition, are still controversial and discussed. This paper deals with a narrative literature review, which includes selected journal articles, conference proceedings and grey literature, on the assessment, acceptable criteria and corrosion mechanism of carbon steel structures in CP condition with AC interference. The study shows that the assessment of AC corrosion likelihood should be based on the measurement of AC and DC (direct current) related parameters, namely AC voltage, AC and DC densities and potential measurements. Threshold values of the mentioned parameters are discussed. Overprotection (EIR-free < −1.2 V vs. CSE) is the most dangerous condition in the presence of AC: the combination of strong alkalization close to the coating defect due to the high CP current density and the action of AC interference provokes localized corrosion of carbon steel.

The study of the electrochemical properties of zinc-rich coating on the base of water sodium silicate

2019 ◽  
Vol 24 (4) ◽  
pp. 51-58
Author(s):  
Le Hong Quan ◽  
Nguyen Van Chi ◽  
Mai Van Minh ◽  
Nong Quoc Quang ◽  
Dong Van Kien
Keyword(s):  
Carbon Steel ◽  
Electrochemical Properties ◽  
Sodium Silicate ◽  
Cathodic Protection ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Electrical Contact ◽  
Electrochemical Impedance Spectra ◽  
Pure Zinc ◽  
Electric Circuits

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.

An Array of Multielectrodes for Locating, Visualizing, and Quantifying Stray Current Corrosion

CORROSION ◽  
10.5006/2828 ◽  
2018 ◽  
Vol 74 (10) ◽  
pp. 1093-1101 ◽  
Author(s):  
Ke Wang ◽  
Facundo Bob Varela ◽  
Mike Yongjun Tan
Keyword(s):  
Cathodic Protection ◽  
Laboratory Simulation ◽  
Buried Pipeline ◽  
Stray Current ◽  
Simulation Experiments ◽  
Corrosion Rates ◽  
Pipeline Corrosion ◽  
Probe Array

An array of multielectrode corrosion probes, designed based on a series of coupled wire beam electrodes (WBEs), has been devised as a new tool for locating, visualizing, and quantifying the effects of stray currents on buried pipeline corrosion. It has been demonstrated in laboratory simulation experiments that this WBE probe array is capable of detecting stray current corrosion affected sites along a pipeline, visualizing stray current corrosion patterns and corrosion rates, and evaluating the efficiency of cathodic protection against stray current corrosion. Based on these results, two applications of this WBE probe array have been proposed for stray current corrosion survey and monitoring.

The Corrosion of Carbon Steel and Stainless Steel in Simulated Geothermal Media

1985 ◽  
Vol 38 (8) ◽  
pp. 1133 ◽  
Author(s):  
BG Pound ◽  
MH Abdurrahman ◽  
MP Glucina ◽  
GA Wright ◽  
RM Sharp
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Stainless Steels ◽  
Polarization Resistance ◽  
Iron Sulfide ◽  
Low Carbon Steel ◽  
Passive Films ◽  
Low Carbon ◽  
Corrosion Rates ◽  
Good Agreement

The corrosion rates of low-carbon steel, and 304, 316 and 410/420 stainless steels in simulated geothermal media containing hydrogen sulfide have been measured by means of the polarization resistance technique. Good agreement was found between weight-loss and polarization resistance measurements of the corrosion rate for all the metals tested. Carbon steel formed a non-adherent film of mackinawite (Fe1 + xS). The lack of protection afforded to the steel by the film resulted in an approximately constant corrosion rate. The stainless steels also exhibited corrosion rates that were independent of time. However, the 410 and 420 alloys formed an adherent film consisting mainly of troilite ( FeS ) which provided only limited passivity. In contrast, the 304 and 316 alloys appeared to be essentially protected by a passive film which did not seem to involve an iron sulfide phase. However, all the stainless steels, particularly the 410 and 420 alloys, showed pitting, which indicated that some breakdown of the passive films occurred.

scholarly journals The effect of volatile organic acids and CO2 on the corrosion rate of carbon steel from a Top-of-Line-Corrosion (TLC) perspective

2021 ◽  
Vol 1201 (1) ◽  
pp. 012079
Author(s):  
S B Gjertsen ◽  
A Palencsar ◽  
M Seiersten ◽  
T H Hemmingsen
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Organic Acid ◽  
Carbonic Acid ◽  
Acid Corrosion ◽  
Iron Concentration ◽  
Critical Factor ◽  
Steel Corrosion ◽  
Carbon Steels ◽  
Corrosion Rates

Abstract Models for predicting top-of-line corrosion (TLC) rates on carbon steels are important tools for cost-effectively designing and operating natural gas transportation pipelines. The work presented in this paper is aimed to investigate how the corrosion rates on carbon steel is affected by acids typically present in the transported pipeline fluids. This investigation may contribute to the development of improved models. In a series of experiments, the corrosion rate differences for pure CO2 (carbonic acid) corrosion and pure organic acid corrosion (acetic acid and formic acid) on X65 carbon steel were investigated at starting pH values; 4.5, 5.3, or 6.3. The experiments were conducted in deaerated low-salinity aqueous solutions at atmospheric pressure and temperature of 65 °C. The corrosion rates were evaluated from linear polarization resistance data as well as mass loss and released iron concentration. A correlation between lower pH values and increased corrosion rates was found for the organic acid experiments. However, the pH was not the most critical factor for the rates of carbon steel corrosion in these experiments. The experimental results showed that the type of acid species involved and the concentration of the undissociated acid in the solution influenced the corrosion rates considerably.

scholarly journals Corrosion Behavior of Copper and Carbon Steel in Acidic Media

2014 ◽  
Vol 11 (4) ◽  
pp. 1577-1582
Author(s):  
Baghdad Science Journal
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Acidic Media ◽  
Corrosion Rates ◽  
Weight Loss Method ◽  
Acid Environment ◽  
Loss Method

The corrosion behavior of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) has been studied. The corrosion inhibition of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) by Ciprofloxacin has been investigated. Specimens were exposed in the acidic media for 7 hours and corrosion rates evaluated by using the weight loss method. The effect of temperature (from 283 ºK to 333 ºK), pH (from 1to 6), inhibitor concentration (10-4 to 10-2) has been studied. It was observed that sulphuric acid environment was most corrosive to the metals because of its oxidizing nature, followed by hydrochloric acid. The rate of metal dissolution increased with increasing exposure time. Corrosion rates of carbon steel in the acidic media found to be higher.

Coatings Formed on Steel by Cathodic Protection And Their Evaluation by Polarization Measurements

CORROSION ◽  
1963 ◽  
Vol 19 (2) ◽  
pp. 59t-68t ◽  
Author(s):  
W. J. SCHWERDTFEGER ◽  
RAUL J. MANUELE
Keyword(s):  
Weight Loss ◽  
Cathodic Protection ◽  
Protective Coatings ◽  
Salt Water ◽  
The Other ◽  
Carbon Anode ◽  
Zinc Anode ◽  
The Third ◽  
Corrosion Rates ◽  
City Water

Abstract Three steel specimens were continuously exposed in the laboratory for almost 5 years in city water to which was added 3 percent by weight of sodium chloride. Two of these specimens were under continuous cathodic protection, one by current from a zinc anode, and the other by current from a rectifier through a carbon anode. The third specimen was left to corrode freely. As a result of the cathodic protection, carbonates and silicates formed protective coatings which eventually reduced the current density required for protection from about 5 to 0.02 ma/sq ft. A coated specimen, after being without protective current for 32 days (including 12 days out of the salt water), required only 0.3 ma/sq ft for initial protection. The instantaneous corrosion rates on the coated specimens (scratched and unscratched) while without protective currents were measured by changes-in-slope (breaks) in polarization curves. The currents at which breaks occurred in the cathodic curves were found to be related to ΔV/ΔI values from the curves, which values in turn bore a relation to the corrosion rates as measured by weight loss.

Corrosion Behavior of Al-Si-Cr-Cu Bearing Low Carbon Steel in A Cyclic Dry/Wet Laboratory Test

2009 ◽  
Vol 79-82 ◽  
pp. 1017-1020 ◽  
Author(s):  
Hui Shu Zhang ◽  
Dong Ping Zhan ◽  
Song Lian Bai ◽  
Zhou Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
Rust Layer ◽  
Electrochemical Behaviors ◽  
Corrosion Rates ◽  
The Matrix ◽  
Corrosion Behaviors

The corrosion behaviors of Al-Si-Cr-Cu bearing low carbon steel and a reference steel Q235 were tested in a cyclic dry/wet environment containing 0.01mol/L NaHSO3 in laboratory. Rust layers were observed by optical microscope (OM), scanning electron microscopy (SEM) and XRD. The electrochemical behaviors of the steels were studied on the polarization curves and electrochemical impedance spectroscopy (EIS). The results indicate that after 120h corrosion test, the annual corrosion rates of the designed steels reduce 42 % than Q235 at least. The corrosion products are generally iron oxyhydroxides and oxides such as FeOOH, γ-FeOOH, α-FeOOH, γ-Fe2O3, Fe3O4. The α-FeOOH possesses good stabilization mainly exits and can improve the corrosion resistance. There are the enrichments of Cu, Cr, Si and Al in the rust layer close to the matrix, which make the rust layer be more compact and protected. The corrosion currents of the two designed steels are lower than that of Q235, the corrosion potentials are higher than that of Q235 after Tafel fitting. The rust layer impedances of the designed steels are higher than that of Q235.

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