Study on the Electrochemical Behavior of Al-6Zn-0.02In-1Mg-0.03Ti Sacrificial Anodes for Long-Term Corrosion Protection in the Ocean

CORROSION ◽  
10.5006/3404 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 366-372 ◽  
Author(s):  
Mingkun Yang ◽  
Yan Liu ◽  
Zeyao Shi ◽  
Xiaodan Lv ◽  
Bin Liu ◽  
...  
Keyword(s):  
Mass Loss ◽  
Corrosion Product ◽  
Cathodic Protection ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Output Current ◽  
Alloy Anode ◽  
Sacrificial Anodes

After 10 y of service in the ocean, the long-term performance of Al-6Zn-0.02In-1Mg-0.03Ti aluminum alloy sacrificial anodes for steel piles was characterized by mass loss in addition to optical and electron microscopy analysis. The electrochemical behavior was conducted by open-circuit potential with potentiodynamic and potentiostatic polarizations. The results showed that cathodic protection potential was in the range of −0.960 VCSE to −1.103 VCSE. The corrosion type and consumption rate of the alloy anode were related to the output current. In harsh corrosion environments, the alloy anode showed uniform corrosion and lost more mass due to voltage output, therefore more current is needed to fulfill cathodic protection. Otherwise, localized corrosion and less mass loss were observed. The alloy anodes were covered by marine creatures and corrosion product. The corrosion product contained amorphous Al(OH)3 and MgAl2(CO3)(OH)·xH2O which became more crystalline from outside to inside of the alloy anode. A translucent corrosion product was found on the alloy anode surface which contained amorphous Al(OH)3·xH2O with S, along with AlxCly(OH)z·mH2O. The electrochemical performance of the alloy anode was strongly reduced by the coverage of corrosion product. Consequently, the open-circuit potential of the alloy anode increased and the output current decreased. The effect of corrosion product thicknesses on the anodic activation is not remarkable.

Prediction and Measurement of Corrosion Rates of Stainless Steel in Concentrated Sulfuric Acid

CORROSION ◽  
10.5006/0709 ◽  
2013 ◽  
Vol 69 (6) ◽  
pp. 543-550 ◽  
Author(s):  
S. Jones ◽  
K. Coley ◽  
J. Kish
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Corrosion Behavior ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Corrosion Rates ◽  
Transient Nature ◽  
Concentrated Sulfuric Acid

When exposed to concentrated sulfuric acid, stainless steel exhibits unique electrochemical behavior. This behavior can be observed as an oscillation in open-circuit potential between the active and passive states. The transient nature of the corrosion behavior under these conditions results in a distinct challenge for measuring and predicting corrosion rates. Using a series of commercial alloys with various nickel contents, this paper outlines the utilization of electrochemical experimentation to refine the prediction of corrosion rates. The paper also discusses some of the difficulties associated with many traditional electrochemical techniques such as potentiodynamic scans when used for characterizing systems that undergo oscillations in open-circuit potential.

Effect of Bi Addition on the Electrochemical Behavior of Zinc Electrodes in Concentrated Alkaline Solutions

2013 ◽  
Vol 805-806 ◽  
pp. 1240-1249
Author(s):  
Hong Xia Liang ◽  
Fu Rong Li ◽  
Zhi Lin Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Linear Polarization ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Exchange Current ◽  
Zinc Electrode ◽  
Current Densities ◽  
Scanning Electron

The electrochemical behavior of zinc electrode with bismuth addition in 35%KOH solutions has been investigated systematically by electrochemical methods including linear polarization, potentiostatic polarization, potential-time measurements at a constant current density, combining the observations of scanning electron microscopy (SEM). Linear polarization results showed that the open circuit potential shifted positively with increasing bismuth content, which is explained based on the gassing data and change in the exchange current of the zinc electrode. Addition of bismuth increased the exchange current of zinc reaction and caused an increase in the measured open circuit potential. Galvanostatic results showed that the addition of bismuth shortened the passivation time. Scanning electron microscopy images showed that the addition of bismuth aggravated the corrosion of zinc electrode which may be responsible for the increased tendency to passivation at high current densities. It has been found that at low current densities the reaction kinetics may be increased by addition of Bi, which is general agreement with the discharging test of actual alkaline batteries.

Copper corrosion behaviour in acidic sulphate media in the presence of 5-methyl-1H-benzotriazole and 5-chloro-1H-benzotriazole

2015 ◽  
Vol 0 (0) ◽  
Author(s):  
Zaklina Z. Tasic ◽  
Milan M. Antonijevic
Keyword(s):  
Mass Loss ◽  
Acidic Medium ◽  
Open Circuit Potential ◽  
Corrosion Behaviour ◽  
Open Circuit ◽  
Chloride Ions ◽  
Copper Corrosion ◽  
Potentiodynamic Polarisation ◽  
Sulphate Media ◽  
Acidic Sulphate

AbstractThe influence of 1H-benzotriazole, 5-methyl-1H-benzotriazole and 5-chloro-1H-benzotriazole on copper corrosion in an acidic sulphate medium was studied, as well as the influence of chloride ions on the corrosion behaviour of copper. The methods used were potentiodynamic measurements, open circuit potential and mass loss. The results show that the examined compounds possess good inhibitory properties in an acidic medium. The potentiodynamic polarisation results indicate that the degree of copper protection against corrosion depends on the concentration of Cl

Effects of Titanium Combined with Aluminium on the Electrochemical Properties and Efficiency of Mg-Mn Anodes

2011 ◽  
Vol 264-265 ◽  
pp. 783-788
Author(s):  
E. Fadaei ◽  
M. Emamy ◽  
C. Dehghanian ◽  
M. Karshenas
Keyword(s):  
Electrochemical Properties ◽  
Cathodic Protection ◽  
Electrochemical Behavior ◽  
Titanium Content ◽  
Short Term ◽  
Electrochemical Tests ◽  
Sacrificial Anodes ◽  
Protection Systems ◽  
Work Samples ◽  
Magnesium Anode

Magnesium sacrificial anodes are widely used in cathodic protection systems. In the present work, samples of Mg-0.7% Mn- x% Al- y% Ti (x,y = 0-0.6) alloys were electrochemically characterized to evaluate their performance as magnesium sacrificial anodes. The experiments focused on the influence of aluminium and titanium contents on the electrochemical behavior and efficiency of anodes. Aluminium and titanium was used in different concentrations ranging from 0.15 to 0.60 at.%. Short-term electrochemical tests, ASTM G97-89, as well as polarization curves were performed to obtain electrochemical behavior and efficiency and to reveal any tendencies to be passive. It is shown that by increasing titanium content an improvement of electrochemical properties of magnesium anode such as current capacity and electrochemical efficiency can be obtained.

Effect of Different Ca Content on Microstructure and Electrochemical Performance of As-Cast AZ31 Magnesium Alloy Sacrificial Anodes

2013 ◽  
Vol 431 ◽  
pp. 42-47
Author(s):  
Hong Wei Cui ◽  
Ting Bin Li ◽  
Xiao Hong Du ◽  
Hong Wei Ding ◽  
Guang Hui Min
Keyword(s):  
Electrochemical Performance ◽  
Grain Refinement ◽  
Open Circuit Potential ◽  
Volume Fraction ◽  
Open Circuit ◽  
Sacrificial Anodes ◽  
Effective Current ◽  
Marketing Application ◽  
Ca Addition ◽  
Second Phases

The effect of ca on the as-cast microstructure and electrochemical performance of AZ31 anode was investigated. The results show that addition of Ca to AZ31 anodes can result in not only grain refinement, but also a change in both morphology and volume fraction of the second phases. And grain refinement by Ca addition can be explained by the GRF mechanism. 0.4%Ca addition to as-cast AZ31 anode can increase the effective current capacity and current efficiency, and meet the requirements of magnesium sacrificial anode, but open circuit potential is lower than the nation standards. AZ31-0.4Ca anode will have a broad marketing application prospect.

Microstructure Dependence of Stress Corrosion Cracking Initiation in X-65 Pipeline Steel Exposed to a Near-Neutral pH Soil Environment

CORROSION ◽  
2004 ◽  
Vol 60 (3) ◽  
pp. 275-283 ◽  
Author(s):  
R. Chu ◽  
W. Chen ◽  
S.-H. Wang ◽  
F. King ◽  
T. R. Jack ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Stress Corrosion ◽  
Soil Solution ◽  
Open Circuit Potential ◽  
Pipeline Steel ◽  
Open Circuit ◽  
Polished Surface ◽  
Soil Environment ◽  
Neutral Ph

Abstract A study was carried out to understand mechanisms of stress corrosion crack initiation in an X-65 pipeline steel exposed to a near-neutral pH soil environment under a mechanical loading condition typical of a pipeline operating in the field. Microcracks initiated on the polished surface of the X-65 pipeline steel after long-term exposure at open-circuit potential in a near-neutral pH synthetic soil solution. It was found that these microcracks were initiated mostly from pits at metallurgical discontinuities such as grain boundaries, pearlitic colonies, and banded phases in the steel. Strong preferential dissolution was observed along planes of the banded structures in the steel. Selective corrosion at these metallurgical discontinuities is attributed to the anodic nature of those areas relative to the neighboring steel surface. Consistent with previous observations, no increased susceptibility to crack initiation was found at physical discontinuities mechanically introduced into the surface of steel exposed to synthetic soil solution at open-circuit potential.

scholarly journals Electrochemical behavior of tantalum in potassium hydroxide solutions

2018 ◽  
Author(s):  
Irena Ljubomir Mickova
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behavior ◽  
Potassium Hydroxide ◽  
Open Circuit Potential ◽  
Cathodic Polarization ◽  
Film Formation ◽  
Open Circuit ◽  
Passive Region ◽  
M 10 ◽  
Stable Passive

<p class="PaperAbstractTitle"><em>The electrochemical behavior of tantalum in various concentrations of KOH solutions <br /> (0.1 M - 10 M), was investigated using the evolution of the open circuit potential in time, cyclic voltammetry and ellipsometric measurements. Depending on KOH concentrations, the open circuit potential measurements have shown three distinct behaviors concerning oxide film formation on the electrode surface and its dissolution. The cyclic voltammetry measurements were performed in various potential ranges, from -1.4 to 8 V, different concentrations of KOH solutions (0.1-10 M) and sweep rates ranging from 0.005 V/s to 1 V/s. In the passive region, very stable passive films were formed, which reduction has not been possible during cathodic polarization even at highly concentrated KOH solutions. In the trans-passive region, the very strong peak at 1.65 V was monitored, which nature and chemical composition is still not well known. </em></p>

Electrochemical Behavior of Potassium Zinc Phosphates Extract and Coating

2012 ◽  
Vol 152-154 ◽  
pp. 64-67 ◽  
Author(s):  
Dong Ping Wei ◽  
Shao Mei Ma ◽  
Ze Guang Zhou ◽  
Zeng Wei Huang ◽  
Ai Qun Yuan ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Corrosive Medium ◽  
Open Circuit Potential ◽  
Zinc Phosphate ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Immersion Test ◽  
Open Circuit ◽  
Zinc Phosphates ◽  
Pigment Extract

The electrochemical corrosion inhibitions of potassium zinc phosphate were studied by polarization, open circuit potential measurements, electrochemical impedance of the pigment extract and coating immersion test. Dynamic analysis shows that in pH=7 3.5% NaCl extract, KZn2(PO4)(HPO4) functions as a cathodic inhibitor on steel and its efficiency is even superior to other phosphates. The inhibiting efficiency of the pigments on steel decrease in the order: KZn2(PO4)(HPO4) > aluminum zinc phosphate > zinc phosphate ≧ aluminum triphosphate The coating tests show that potassium zinc phosphate can efficiently enhance the inhibition properties of coating and prevent the erosion of the corrosive medium by improving the barrier and hydrophobicity of the coating. The anticorrosive property of the pigments decrease in the order: KZn2(PO4)(HPO4)> aluminum zinc phosphate > zinc phosphate ≈APW-1.

scholarly journals Long-Term Assessment of the In Vitro Corrosion Resistance of Biomimetic ACP Coatings Electrodeposited from an Acetate Bath

2021 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Patrycja Osak ◽  
Joanna Maszybrocka ◽  
Julian Kubisztal ◽  
Patryk Ratajczak ◽  
Bożena Łosiewicz
Keyword(s):  
Corrosion Resistance ◽  
Calcium Phosphate ◽  
Surface Characterization ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Pure Titanium ◽  
Open Circuit

Calcium phosphate coatings are able to improve the osseointegration process due to their chemical composition, which is similar to that of bone tissues. In this work, to increase the long-term corrosion resistance and to improve the osseointegration process of commercially pure titanium Grade 4 (CpTi G4), biomimetic amorphous calcium phosphate (ACP) coatings were electrodeposited for the first time from an acetate bath with a pH level of 7.0 and a Ca:P ratio of 1.67. ACP coatings were obtained on CpTi G4 substrate subjected to sandblasting and autoclaving using electrochemically assisted deposition at a potential of −3 V relative to the open circuit potential for 30 min at room temperature. SEM, EDS, 2D roughness profiles, amplitude-sensitive eddy current method, and Kelvin scanning probe were used for the surface characterization of the biomaterial under study. In vitro corrosion resistance tests were conducted for 21 days in artificial saliva using open circuit potential, polarization curves, and electrochemical impedance spectroscopy measurements. The passive-transpassive behavior was revealed for the obtained ACP coatings. The long-term corrosion resistance test showed a deterioration of the protective properties for CpTi G4 uncoated and coated with ACP with immersion time. The mechanism and kinetics of the pitting corrosion on the CpTi G4|TiO2|ACP coating system are discussed in detail.

Sign in / Sign up

Export Citation Format

Share Document