scholarly journals Stress Corrosion Behavior of Ungrouted Pretensioned Concrete Beams

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Velu Saraswathy ◽  
Han-Seung Lee ◽  
Subbiah Karthick ◽  
Seung-Jun Kwon
Keyword(s):  
Stress Corrosion ◽  
Corrosion Behavior ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Steel Wire ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Simultaneous Action ◽  
Corrosive Media ◽  
Potential Measurement

Prestressed concrete beams of size 150 × 150 × 1000 mm were designed, and two bonded cold-drawn 7 mm steel wires were stressed at 70% UTS under service conditions before concreting. The beams were cast with M40 grade concrete mix with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of cement and cured for 28 days. After 28 days, the stretching forces were released, the prestressing steel wire was allowed to regain its original length, the tensile stresses were transformed into a compressive stress in the concrete, and the stress corrosion behavior was assessed. Stress corrosion cracking (SCC) is due to the simultaneous action of stress, corrosive media, and material properties. The stress corrosion behavior of ungrouted pretensioned steel was assessed by using various electrochemical techniques such as electrochemical noise, open-circuit potential measurement, AC impedance, and potentiodynamic polarization measurements. The same experiments were conducted for rebars embedded in the concrete beam with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of chloride. After 30 days of exposure, the beams were tested for their flexural strength measurements to find out the load-bearing capacity.

THE EFFECT OF IMMERSION TIME ON THE CORROSION BEHAVIOR OF SUS304 IN BRINE USING HALF-CELL POTENTIAL MEASUREMENT

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Saber Rashid ◽  
N. Islami ◽  
A. K. Ariffin ◽  
M. Ridha ◽  
S. Fonna
Keyword(s):  
Stress Corrosion ◽  
Corrosion Behavior ◽  
Immersion Time ◽  
Plastic Anisotropy ◽  
Internal Stresses ◽  
Half Cell ◽  
Cell Potential ◽  
Potential Measurement ◽  
G 38 ◽  
The Impact

The aim of this study is to investigate the impact of immersion time, at different time values for two cases, with stressed and no stressed on materials. This study is conducted using SUS304 material with the presence of 3.5% NaCl at the range of stresses for the specimens lower than the yield strength.  The geometry of the C-ring specimen was selected for 18.974 mm and 1.244 mm for the outer diameters and the thickness respectively. The immersion time effect was investigated using the half-cell potential measurement following the ASTM G-38 standard. The approach of corrosion environment was applied to resemble the condition of loading history. Three levels of stresses were designed and applied in finite element analysis and the results known as the parameters of stress-corrosion measurement. The ASTM G-38 standard is prominent for making C-ring stress-corrosion for elastic stress analysis. The stress-corrosion test was performed at two parameters, fixed stress and no stress. The value of stresses for fixed stress was chosen for 179.199 MPa, 328.665 MPa and 460.131 MPa, correspondingly. The immersion time were selected from 0, 10 and 30 days. The electrochemical result shows that the immersion time did not affect vastly to the corrosion behavior for no stress-corrosion compared with fixed stress. The corrosion rate increases proportionally with the time immersion increments due to the inability of the steel layer protection to regenerate itself. Subsequently, it is also due to the metal was exposed to plastic deformation that resulting the internal stresses due to the plastic anisotropy of the grains.

scholarly journals Data on the Microstructure and Passivation Behavior for NO7718 and NO7208 Nickel Alloys in Corrosive Media

2018 ◽  
Vol 34 (5) ◽  
pp. 2435-2439
Author(s):  
Roland Tolulope Loto
Keyword(s):  
Nickel Alloys ◽  
Chloride Ion ◽  
Open Circuit ◽  
Ion Concentration ◽  
Polarization Data ◽  
Corrosive Media ◽  
Potential Measurement ◽  
Passive Behavior ◽  
Qualitative Relationship ◽  
Transition Curves

Potentiodynamic polarization data for nickel alloys N07718 and N07208 in 2M H2SO4 solution at 0% - 5% NaCl concentrations are presented in tabular form showing the qualitative relationship between the corrosion resistance, passivation behavior and interfacial redox reactions of the alloys with the increase in chloride ion concentration. Tafel plots from the polarization test are presented to show the anodic-cathodic transition curves with respect to variable applied potential and scan rate. Data on open circuit potential measurement for the 1200s showed the active-passive behavior of both alloys and their thermodynamic stability in the acid solution. Optical micro-analytical images of the alloys before corrosion and at 0%, 0.5% and 5% NaCl after corrosion are presented for morphological and comparative analysis.

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.

Comparative Study of the Corrosion Behavior of Low-Nickel AISI 202 and Conventional AISI 304 Stainless Steels in Citric Acid Using Electrochemical Techniques

2016 ◽  
Vol 835 ◽  
pp. 131-135 ◽  
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena
Keyword(s):  
Stainless Steel ◽  
Citric Acid ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Corrosion Current ◽  
Open Circuit ◽  
Corrosion Mechanism ◽  
Protective Film ◽  
Aisi 304

Stainless steel (SS) is one of the most commonly used metallic food contact materials. It may be classified based on its microstructure whether ferritic, austenitic, martensitic, duplex or precipitation hardened. Austenitic SS, among mentioned grades, has the largest contribution to market due to its numerous industrial and domestic applications. In this study, the corrosion behavior of AISI 202 SS – a cheaper grade of stainless steel, in three different solution temperatures of citric acid was investigated using different electrochemical techniques such as open-circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results were compared to that obtained from conventional AISI 304 SS. OCP, polarization and impedance measurements agreed that AISI 202 SS has comparable resistance to that of AISI 304 SS in citric acid at ambient temperature and at 50 °C. At 70 °C, results of OCP measurements suggest that AISI 304 SS exhibited greater performance as indicated by more positive OCP values in the designated solution. EIS results indicate that the two alloys have identical corrosion resistance even at 70 °C as indicated by their comparable polarization resistance (Rp). The corrosion mechanism in both alloys is charge-transfer controlled as indicated by depressed semi-circular appearance of the generated Nyquist plots. The values of corrosion current densities (icorr) extracted from polarization curves indicate that the initial corrosion rates were higher in AISI 304 than AISI 202 SS suggesting that formation of more protective film may have occurred on the former alloy.

Electrochemical Investigation of the Effects of Acid Concentration and Dissolved Oxygen on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid

2016 ◽  
Vol 835 ◽  
pp. 115-120
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena
Keyword(s):  
Corrosion Resistance ◽  
Citric Acid ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Human Consumption ◽  
Face Centered Cubic

All materials which are intended to have in contact with food and other commodities produced or processed for human consumption are called food contact materials (FCM’s). Stainless steel (SS) – a widely known metallic FCM is used mainly in processing equipment, containers and household utensils. It is known for having numerous industrial and domestic applications worldwide due to its special characteristics of having notable corrosion resistance. However, this corrosion resistance is not all-encompassing since SS may still undergo degradation when subjected to a specific corrosion-inducing environment. SS may be classified according to its microstructure. If the atoms which make up the SS can be viewed as having a face-centered cubic structure, then the alloy is said to be austenitic. This SS grades include the conventional 300-series and the newly-developed 200-series. The former has superior corrosion resistance while the latter is far cheaper. In this study, the corrosion behavior of AISI 202 SS in two different levels of dissolved oxygen (O2) and three acid concentrations was investigated using electrochemical techniques, namely, open-circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). As the concentration of citric acid is increased, the measured OCP values of the alloy decreased and the polarization resistance (Rp) decreased, indicating decrease in alloy stability and decline in the corrosion resistance, respectively. With regards to effects of dissolved O2, results revealed that increasing the level of dissolved O2 has consequently increased the polarization resistance and shifted the OCP to more positive values. All the generated Nyquist plots exhibited a depressed capacitive loops indicating that corrosion in the designated solution occurred with charge transfer as the rate-determining step.

scholarly journals Electrochemical Study of Ni20Cr Coatings Applied by HVOF Process in ZnCl2-KCl at High Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
J. Porcayo-Calderón ◽  
O. Sotelo-Mazón ◽  
M. Casales-Diaz ◽  
J. A. Ascencio-Gutierrez ◽  
V. M. Salinas-Bravo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
304 Stainless Steel ◽  
Experimental Conditions ◽  
Corrosive Media ◽  
Linear Polarization Resistance ◽  
Potentiodynamic Polarization Curves ◽  
Hvof Process ◽  
Oxygen Fuel

Corrosion behavior of Ni20Cr coatings deposited by HVOF (high velocity oxygen-fuel) process was evaluated in ZnCl2-KCl (1 : 1 mole ratio) molten salts. Electrochemical techniques employed were potentiodynamic polarization curves, open circuit potential, and linear polarization resistance (LPR) measurements. Experimental conditions included static air and temperatures of 350, 400, and 450°C. 304-type SS was evaluated in the same conditions as the Ni20Cr coatings and it was used as a reference material to assess the coatings corrosion resistance. Coatings were evaluated as-deposited and with a grinded surface finished condition. Results showed that Ni20Cr coatings have a better corrosion performance than 304-type SS. Analysis showed that Ni content of the coatings improved its corrosion resistance, and the low corrosion resistance of 304 stainless steel was attributed to the low stability of Fe and Cr and their oxides in the corrosive media used.

scholarly journals Stress Corrosion Behavior of AM50Gd Magnesium Alloy in Different Environments

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 616 ◽  
Author(s):  
Miao Yang ◽  
Xiaobo Liu ◽  
Zhiyi Zhang ◽  
Yulai Song
Keyword(s):  
Magnesium Alloy ◽  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Anodic Dissolution ◽  
Corrosion Behavior ◽  
Pure Water ◽  
Corrosion Current ◽  
Open Circuit ◽  
Distilled Water ◽  
Corrosion Properties

A new type of high strength corrosion-resistant magnesium alloy was prepared by adding 1% rare earth Gd to AM50 and then treated with hot extrusion method. The stress corrosion properties of the new materials in air, pure water, 0.5 mol/L NaCl, and 0.5 mol/L Na2SO4 solution were studied by the slow strain rate tensile (SSRT) test, in situ open circuit potential test, Tafel curve test, stereomicroscope, SEM, and EDS. The results showed the following. The stress corrosion sensitivity of the material in different environments was Na2SO4 > NaCl > distilled water > air. According to the Tafel curves measured at 0 and 100 MPa, the corrosion voltage decreased little and the corrosion current density increased rapidly under 100 Pa. This was because the film of the corrosion product ruptured to form a large cathode and a small anode, which resulted in a large instantaneous corrosion current. The mechanism of hydrogen embrittlement and anodic dissolution together affected the stress corrosion behavior of the alloy. In distilled water, hydrogen embrittlement played a major role, while in NaCl and Na2SO4 solution, hydrogen embrittlement and anodic dissolution were both affected. The direct reason of the stress corrosion crack (SCC) samples’ failure was the cracks expanding rapidly at the bottom of pit, which was caused by corrosion.

scholarly journals Corrosion Behavior of Some Timonb Alloys in Ringer Solution

2020 ◽  
Vol 71 (7) ◽  
pp. 187-196
Author(s):  
Maria Magdalena Pricopi ◽  
Romeu Chelariu ◽  
Nicolae Apostolescu ◽  
Doina-Margareta Gordin ◽  
Daniel Sutiman ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Immersion Time ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Electrochemical Techniques ◽  
Ringer Solution ◽  
Open Circuit ◽  
Chemical Compositions ◽  
Solution Ph

The aim of this study was to investigate the influence of different process parameters as chemical composition, the pH value and immersion time on the corrosion of the some TiMoNb alloys, using different electrochemical techniques such as: cyclic voltammetry, open circuit potential (OCP) measurement, polarization curves and electrochemical impedance spectroscopy (EIS). The alloys were analyzed in the natural pH of the Ringer solution, but also with an acidic modification of the solution (ph = 4) and a basic modification (ph = 8). The more acidic values of pH, the more evident are differences between corrosion behavior of titanium-based alloys depending on their chemical compositions and immersion times.

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