Long-Term Sour Corrosion of Carbon Steel in Anoxic Conditions

CORROSION ◽  
10.5006/3441 ◽  
2020 ◽  
Vol 76 (3) ◽  
pp. 324-331 ◽  
Author(s):  
M. Goldman ◽  
J.J. Noël ◽  
D.W. Shoesmith
Keyword(s):  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Steel Surface ◽  
Corrosion Potential ◽  
Steel Substrate ◽  
Relative Polarization ◽  
Alkaline Conditions ◽  
Sour Corrosion ◽  
Corrosion Of Steel

Coatings and cathodic protection of pipelines can fail leading to exposure of underlying steel substrate to environmental conditions. In Canada, these conditions are typically alkaline and can contain dissolved sulfides. Sulfides are known to accelerate corrosion of steel, however, the corrosion behavior may differ if a preformed oxide or oxyhydroxide is present on the steel surface. This study investigates the change in corrosion behavior of steel in anoxic alkaline conditions that is directly exposed to sulfide or has a preformed surface oxide. The electrochemical response (corrosion potential and polarization resistance) were monitored for 90 d and 120 d, while simultaneously monitoring the film composition and morphology by Raman spectroscopy and scanning electron microscopy, respectively. In the absence of a preformed oxide the mackinawite film was able to undergo anoxic aging to greigite and pyrite whereas the electrodes with a preformed film had only mackinawite present on the surface. The interconversion of mackinawite to greigite and pyrite lead to a higher relative polarization resistance than the electrode with the preformed oxide.

The Preparation of Coatings with Codepositon Plating on A3 Steel and its Corrosion Resistance

2010 ◽  
Vol 150-151 ◽  
pp. 1034-1038
Author(s):  
Shang Dong Chen ◽  
Ting Sun ◽  
Hong Nian
Keyword(s):  
Corrosion Resistance ◽  
Polarization Resistance ◽  
Polarization Effect ◽  
Corrosion Potential ◽  
Steel Substrate ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Plain Carbon Steel ◽  
Cathode Polarization ◽  
Electrochemical Corrosion Behavior

A new method for preparation of coatings with codeposition plating on the ordinary A3 steel and heat treatment later. Research the coatings on electrochemical corrosion behavior variation in Q-sun. Results show that corrosion potential shuffle, corrosion current density reduced nearly two number magnitudes value, polarization resistance increased, the cathode polarization effect enhanced obviously in polarization curves, and self-corrosion current reduced, impedance increased twenty times in alternating current impedance atlas than A3 steel substrate without coatings. It was indicated that the coating improve effectively the corrosion resistance of plain carbon steel.

Corrosion Behavior and Mechanism of a Cu-Ni Alloy in Marine Environment

2008 ◽  
Vol 385-387 ◽  
pp. 385-388
Author(s):  
Qing Fen Li ◽  
Chun Hui Li ◽  
Ying Jie Qiao
Keyword(s):  
Corrosion Behavior ◽  
Marine Environment ◽  
Pitting Corrosion ◽  
Polarization Resistance ◽  
Corrosion Potential ◽  
Corrosion Process ◽  
Sulfate Reducing ◽  
Sterile Seawater ◽  
Ni Alloy ◽  
Reducing Bacteria

The microbiological influenced corrosion (MIC) behavior of a marine pipeline Cu-Ni alloy in the sterile seawater and sulfate-reducing bacteria (SRB) solution was investigated. Results show that severe pitting corrosion appeared on the specimens in the SRB solution. The corrosion potential of specimen in the SRB solution was much lower than that in the sterile seawater and the polarization resistance of specimen in the SRB solution decreased quickly after a period immersion and became much lower than that in the sterile seawater. Besides, the results of EDS and XRD show that the content of element Ni and Fe of the Cu-Ni alloy decreased greatly and the high content of element S appeared after 30 days immersion in the SRB solution. It was concluded that the SRB accelerated the corrosion process of the Cu-Ni alloy greatly. The MIC mechanism of the alloy in marine environment is discussed.

scholarly journals Effect of Cu content on the Electrochemical Corrosion Behavior of Peak-aged Al-6Si-0.5Mg Alloys in Sodium Chloride Solution

2016 ◽  
Vol 44 ◽  
pp. 29-35
Author(s):  
Abul Hossain ◽  
M. A. Gafur ◽  
Fahmida Gulshan ◽  
A. S. W. Kurny
Keyword(s):  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Potential ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Test Results ◽  
Nacl Solution ◽  
Cu Content ◽  
Electrochemical Corrosion Behavior ◽  
Peak Aged

The purpose of this study is to understand the electrochemical corrosion behavior of 1wt% Cu content Al-6Si-0.5Mg alloy in 0.1M NaCl solution. The potentiodynamic polarization curves reveal that 1wt% Cu content alloy is less prone to corrosion than the Cu free alloy. The EIS test results show that corrosion resistance or polarization resistance (Rct) increases with the addition of 1wt% Cu to Al-6Si-0.5Mg alloy. Higher polarization resistance (Rp) has been obtained with the addition of 1wt% Cu to the Al-6Si-0.5Mg alloy. Due to addition of Cu and thermal modification, the magnitude of open circuit potential (OCP), corrosion potential (Ecorr) and pitting corrosion potential (Epit) of Al-6Si-0.5Mg alloy in NaCl solution were shifted to the more noble direction.

scholarly journals Effect of Recrystallization Annealing on Corrosion Behavior of Ta-4%W Alloy

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 117 ◽  
Author(s):  
Guoqiang Ma ◽  
Qiongyao He ◽  
Xuan Luo ◽  
Guilin Wu ◽  
Qiang Chen
Keyword(s):  
Corrosion Resistance ◽  
Anodic Dissolution ◽  
Corrosion Behavior ◽  
Current Density ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Recrystallization Annealing ◽  
Site Lattice

The effect of recrystallization annealing on corrosion behavior of Ta-4%W alloy was studied. It is found that the deformed sample contains high dense dislocations and dislocation boundaries. During annealing, these dislocations and dislocation boundaries are replaced by recrystallizing grains until the alloy is fully recrystallized. Both the anodic dissolution and the cathodic activity is much more blocked. The corrosion potential gradual shift towards negative values and corrosion current density decrease, while polarization resistance increases after annealing, indicating enhanced corrosion resistance of the alloy. Such an enhancement is caused by the increase of low-Σ coincide site lattice boundaries and decrease of dislocations and dislocation boundaries.

Influence of sulfate reducing bacteria on the cupronickel corrosion

2014 ◽  
Vol 61 (6) ◽  
pp. 395-401
Author(s):  
Liu Kecheng ◽  
Liu Xia ◽  
Long Xiao ◽  
Wei Jiaqiang ◽  
Hu Mengsha ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Sulfate Reducing Bacteria ◽  
Free Corrosion Potential ◽  
Content Type ◽  
Linear Polarization Resistance ◽  
Sulfate Reducing ◽  
Reducing Bacteria

Purpose – The purpose of this study is to explore the influence of the sulfate reducing bacteria (SRB) on the corrosion of cupronickel. Design/methodology/approach – Tests monitoring the change in free corrosion potential, linear polarization resistance and electrochemical impedance spectroscopy and examination using the scanning electron microscope and energy spectrum analysis were used to investigate the corrosion behavior of cupronickel in blank medium and in media inoculated with SRB to explore the influence of the SRB on the corrosion behavior of cupronickel alloy. Findings – The results show that SRB can destroy the surface oxide film of cupronickel and significantly reduce the free corrosion potential and polarization resistance of the cupronickel, causing the cupronickel to corrode significantly. Originality/value – SRB are widely found in the water supply system and is one of the important factors inducing microbial corrosion. This paper verified that SRB promote cupronickel corrosion and explored the influence and mechanism of attack.

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

scholarly journals Robust Carbon-Stabilization of Few-Layer Black Phosphorus for Superior Oxygen Evolution Reaction

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 695 ◽  
Author(s):  
Mengjie Zhang ◽  
Wenchang Zhu ◽  
Xingzhe Yang ◽  
Meng Feng ◽  
Hongbin Feng
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Black Phosphorus ◽  
Carbon Stabilization ◽  
High Durability ◽  
Carbon Coated ◽  
Alkaline Conditions ◽  
Doped Graphene ◽  
A Current

Few-layer exfoliated black phosphorus (Ex-BP) has attracted tremendous attention owing to its promising applications, including in electrocatalysis. However, it remains a challenge to directly use few-layer Ex-BP as oxygen-involved electrocatalyst because it is quite difficult to restrain structural degradation caused by spontaneous oxidation and keep it stable. Here, a robust carbon-stabilization strategy has been implemented to prepare carbon-coated Ex-BP/N-doped graphene nanosheet (Ex-BP/NGS@C) nanostructures at room temperature, which exhibit superior oxygen evolution reaction (OER) activity under alkaline conditions. Specifically, the as-synthesized Ex-BP/NGS@C hybrid presents a low overpotential of 257 mV at a current density of 10 mA cm−2 with a small Tafel slope of 52 mV dec−1 and shows high durability after long-term testing.

scholarly journals An electrochemical method to investigate the effects of compound composition on gold dissolution in thiosulfate solution

2020 ◽  
Vol 9 (1) ◽  
pp. 496-502 ◽  
Author(s):  
Zhaohui Zhang ◽  
Bailong Liu ◽  
Mei Wu ◽  
Longxin Sun
Keyword(s):  
Dissolution Rate ◽  
Current Density ◽  
Polarization Resistance ◽  
Electrochemical Method ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Gold Dissolution ◽  
Tafel Polarization ◽  
Edta Solution

AbstractThe electrochemical behavior of gold dissolution in the Cu2+–NH3–S2O32−–EDTA solution has been investigated in detail by deriving and analyzing the Tafel polarization curve, as this method is currently widely implemented for the electrode corrosion analysis. The dissolution rate of gold in Cu2+–NH3–S2O32−–EDTA solution was determined based on the Tafel polarization curves, and the effects of various compound compositions in a Cu2+–NH3–S2O32−–EDTA mixture on the corrosion potential and corrosion current density were analyzed. The results showed that the corrosion potential and polarization resistance decreased, whereas the corrosion current density increased for certain concentrations of S2O32−–NH3–Cu2+ and EDTA, indicating that the dissolution rate of gold had changed. The reason for promoting the dissolution of gold is also discussed.

scholarly journals Corrosion Behavior and Osteogenic Activity of a Biodegradable Orthopedic Implant Mg–Si Alloy with a Gradient Structure

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 781
Author(s):  
Weiyan Jiang ◽  
Wenzhou Yu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Gradient Structure ◽  
Orthopedic Implant ◽  
Biological Functions ◽  
Alloy Matrix ◽  
Osteogenic Activity

A gradient Mg-8 wt % Si alloy, which was composed of the agglomerated Mg2Si crystals coating (GMS8-1) and the eutectic Mg–Si alloy matrix (GMS8-2), was designed for biodegradable orthopedic implant materials. The bio-corrosion behavior was evaluated by the electrochemical measurements and the immersion tests. The results show that a significant improvement of bio-corrosion resistance was achieved by using the gradient Mg–Si alloy, as compared with the traditional Mg-8 wt % Si alloy (MS8), which should be attributed to the compact and insoluble Mg2Si phase distributed on the surface of the material. Especially, GMS8-1 exhibits the highest polarization resistance of 1610 Ω, the lowest corrosion current density of 1.7 × 10−6 A.cm−2, and the slowest corrosion rate of 0.10 mm/year. In addition, GMS8-1 and GMS8-2 show better osteogenic activity than MS8, with no cytotoxicity to MC3T3-E1 cells. This work provides a new way to design a gradient biodegradable Mg alloys with some certain biological functions.

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