scholarly journals Investigation on Corrosion Behaviour of Polymeric Coatings on Weathering Steel Under 3.5% NaCl Solution

2021 ◽  
Author(s):  
Venkatesh R ◽  
S Manivannan ◽  
Kumaresh Babu S P
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Dynamic Test ◽  
Protective Layer ◽  
Immersion Test ◽  
Weathering Steel ◽  
Main Concern ◽  
Low Carbon ◽  
Corrosion Tests

Abstract Weathering steel, a low carbon alloy steel, most widely used in marine transportation and construction fields like bridges, sculptures where corrosion resistance is the main concern. Weathering steel creates an adhering protective coating on its surface in the right environmental conditions. The protective layer which is formed on the surface weathering steel known as patina. It protects the structure from further corrosion to occur. When these weathering steels are continuously exposed to moisture environment its corrosion resistance decreases. So, our investigation deals about the studies of the coatings used on weathering steel to increase its corrosion resistance in marine conditions. The coatings applied on the substrate were poly urea, polyurethane, epoxy and black enamel. Corrosion tests were performed on these coated samples to evaluate their corrosion behaviour in different environments. Corrosion tests that were performed are immersion test, salt spray test and potentio-dynamic test. The profilometry test is investigated and it confirmed the depth of the corrosion on the coatings. Based on the corrosion studies, we conclude that poly urea is the excellent coating followed by polyurethane, black enamel and epoxy.

Effect of Sol-Gel Film on the Corrosion Resistance of Low Carbon Steel Plate

2020 ◽  
Vol 984 ◽  
pp. 43-50
Author(s):  
Hua Yuan Zhang ◽  
Can Wang ◽  
Bing Xue ◽  
Jing Luo
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Steel Plate ◽  
Salt Spray ◽  
Sol Gel ◽  
Low Carbon Steel ◽  
Corrosion Current ◽  
Neutral Salt ◽  
Low Carbon ◽  
Gel Film

To improve the corrosion resistance on Q235 low carbon steel, in this paper, tetraethyl orthosilicate (TEOS), N-dodecyl trimethoxysilane and γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) were used to make organic-inorganic hybrid sol-gel film. Cross cut test adhesion method, neutral salt spray test, electrochemical test and film protective efficiency were taken to value the corrosion resistance property. The corrosion topography was studied by optical microscope. In addition, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) curves and equivalent electric circuit fitting were used to analyze the corrosion mechanism. The cross cut adhesion of sol-gel film can reach 1 class and the protection class can attain 5 class after 72 hours neutral salt spray test. According to the potentiodynamic polarization curve analysis, the corrosion potential of sol-gel film coating sample after 0.5 hours immersion was -0.46 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.74×10-7 A·cm-2. The corrosion potential of bare Q235 low carbon steel plate after 0.5 hours immersion was -0.78 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.75×10-6 A·cm-2. The impedance value on 0.1 Hz (|Z|0.1Hz) (1.27×106 Ω·cm2) of sol-gel film coating sample was more than three orders of magnitude higher than the value of the low carbon steel plate. Even dipping in 3.5 wt. % NaCl for 72 hours, the |Z|0.1Hz value of sol-gel coating sample was still one order of magnitude higher than the low carbon steel plate with 0.5 hours immersion. Sol-gel film with excellent adhesion can significantly improve the corrosion resistance of low carbon steel plate. Sol-gel film can increase the protection efficiency of low carbon steel plate by 90%.

The Influence of Major Defects on the Properties of Continuous Galvanized Steel Sheet

2012 ◽  
Vol 445 ◽  
pp. 661-666 ◽  
Author(s):  
A. Azimi ◽  
F. Shahriari ◽  
F. Ashrafizadeh ◽  
M.R. Toroghinezhad ◽  
J. Jamshidi
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Tensile Test ◽  
Steel Sheet ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Galvanized Steel ◽  
Tafel Polarization ◽  
Steel Sheets ◽  
Bare Spot

Production of defect-free galvanized steel sheet is considered a major concern for automotive and other critical applications; nevertheless, the occurrence of some defects in the coated sheets is unavoidable. In order to alleviate the problem, we need to know the extent to which the properties of a galvanized sheet are influenced by the presence of a given defect. In this investigation, specimens including any of the two major defects of continuously galvanized steel sheets were selected from a large number of coated samples. The defects, including furnace roll pimples and bare spots, were microstructurally characterized and their influence on corrosion behaviour and mechanical properties of the steel sheet was evaluated. Corrosion resistance was examined via standard salt spray test and Tafel polarization. Tensile test was employed as a measure of mechanical properties of the defective galvanized sheets. The results indicated that the presence of defects had little influence on the tensile properties of the samples, but considerably reduced their corrosion resistance. Based on the results of salt spray tests, pimples reduced corrosion resistance of galvanized sheets 23 % (50 hours) on average and bare spot defects caused reduction in corrosion resistance up to 39%.

scholarly journals Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

2016 ◽  
Vol 61 (2) ◽  
pp. 825-832
Author(s):  
A. Grajcar ◽  
B. Grzegorczyk ◽  
A. Kozłowska
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Cold Deformation ◽  
Metallic Matrix ◽  
Corrosion Damage ◽  
Austenitic Steels ◽  
Low Carbon ◽  
Deformation Bands ◽  
Cold Worked ◽  
Corrosion Pits

Abstract Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked). Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

scholarly journals Graphene-Based Coating for Corrosion Application

2019 ◽  
Vol 8 (6S4) ◽  
pp. 378-380
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Molybdenum Oxide ◽  
Chemical Resistance ◽  
Salt Spray ◽  
Immersion Test ◽  
High Mechanical Strength ◽  
Electro Deposition ◽  
Reduced Graphene ◽  
One Step

Graphene-based, molybdenum oxide-based and composite coating were prepared by one-step electro-deposition without using aggressive solutions. The coatings were characterised by Scanning Electron Microscope (SEM). The corrosion resistance of the three coatings were evaluated by immersion test (ASTM G31-72), salt spray test (ASTM B117-16) and potentiodynamicpolarisation, in 5% NaCl and 2% H2SO4 respectively. All of the results indicated that reduced graphene oxide – molybdenum oxide (rGO/MoO) composite coating exhibits the highest corrosion resistance in both saline and acidic environment. This could be ascribed to the synergistic effect of both graphene and molybdenum oxide with the combination of high mechanical strength and superior chemical resistance.

scholarly journals Corrosion Behaviour of Preserved PEO Coating on AZ31 Magnesium Alloy

2020 ◽  
Vol 23 (2) ◽  
pp. B76-B88
Author(s):  
Filip Pastorek ◽  
Milan Štrbák ◽  
Daniel Kajánek ◽  
Martina Jacková ◽  
Jana Pastorková ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Treatment Process ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Tests ◽  
Marine Transport ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

A surface treatment process, composed of plasma electrolytic oxidation (PEO) and sealing by temporary oil preservation system containing corrosion inhibitors, was performed on AZ31 magnesium alloy in order to improve its corrosion resistance in environments containing chlorides. Both atmospheric and immersion conditions were evaluated by electrochemical tests in 0.1M NaCl solution together with salt spray test according to STN EN ISO 9227 standard. The obtained results confirmed significant improvement of corrosion resistance reached by the PEO sealing in aggressive environments compared to the pure PEO coating on AZ31 surface. Hence, such a duplex coating is a very perspective alternative for magnesium alloy applications in severe conditions or for temporary protection of magnesium products coated by the PEO during marine transport.

scholarly journals The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

2014 ◽  
Vol 20 (1) ◽  
pp. 41-52 ◽  
Author(s):  
A. Bakhtiari ◽  
M.R. Toroghinejad ◽  
F. Ashrafizadeh
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Texture Component ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Bath Temperature ◽  
X Ray Diffraction ◽  
Zinc Bath ◽  
Compact Structure ◽  
Galvanized Coatings

The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM). The composition of the coating layers was determined using energy dispersive spectroscopy (EDS) analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2) basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1) prism component, (20.1) high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2) texture component and weaker (20.1) components have better corrosion resistance than the coatings with weak (00.2) and strong (20.1) texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

scholarly journals COMPARATIVE ANALYSIS OF STEEL CORROSION RESISTANCE

2020 ◽  
Vol 1 (2) ◽  
pp. 12-17
Author(s):  
Chao Zhang ◽  
Xiang Yin ◽  
Chun Qing
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Comparative Analysis ◽  
Carbon Steel ◽  
Salt Spray ◽  
Steel Corrosion ◽  
Immersion Test ◽  
Time Interval ◽  
Regular Time ◽  
Threshold Ratio

The objective of the study was to conduct the comparative analysis of steel types corrosion resistance. Three selected steel types were used in the study. The selected types were structural steel, stainless steel, and MMFX steel. The methodology we adopted is that we evaluated the steel parts resistance towards corrosion by doing in-salt spray experiment and the immersion of aqueous solution of sodium chloride. For salt spray test, we used guidelines by ASTM B117. This practice provides a controlled corrosion environment which is used for exposing specimen to salt spray chamber. For immersion test, test specimens are analyzed at regular time interval as the first rust is appeared. For carbon steel, we used three specimen and mostly initial rust appeared in initial 13 to 15 hours. For stainless steel, inter granular corrosion were analyzed. The results show that the first cycle started after about 46 hours; the second cycle started about 1% and the third cycle started with the rage of about 2 to 30%. For MMFX 2 steel, the results show that for MMFX carbon steel, the chloride threshold ratio is about 6 times higher than black bars and more than double of other types. The conclusion of the study is that in big structures like bridges, the MMFX steel should be used.

The Effect of Flue Gas Environment on the Corrosion Behavior of the Sulfuric Acid Dew-Point Corrosion Resistant Steel

2018 ◽  
Vol 941 ◽  
pp. 1705-1709
Author(s):  
Byoung Ho Lee ◽  
Min Ho Jo ◽  
Yun Ha Yoo
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
Immersion Test ◽  
Dew Point ◽  
Corrosion Resistant Steel ◽  
Resistant Steel ◽  
Low Carbon ◽  
Corrosion Resistant

In order to compare the corrosion resistance of conventional low carbon steel, Cu containing low carbon steel for sulfuric acid dew-point corrosion inhibition, and stainless 409L, immersion tests were carried out in 50 wt.% sulfuric acid. The effects of HCl concentraion on the corrosion behavior in a fixed sulfuric acid concentration (16.9 vol.%) was also investigated by immersion test. In addition to immersion test, field test in a thermal plant was carried out for 10 months. As a result, it was confirmed that Cu-containing dew-point corrosion resistent steel has the highest corrosion resistance compared with other materials. To verify superior corrosion resistence of dew-point corrosion resistant steel, surface morpology after various test was observed by SEM. It was found that surface corroded product of the dew-point corrosion resistant steel was much denser and thicker compared with the other steel.

A COMPARATIVE STUDY TO EVALUATE THE CORROSION PERFORMANCE OF FRICTION STIR WELDED AZ31B MAGNESIUM ALLOY UNDER IMMERSION, SALT FOG, PITTING AND GALVANIC CORROSION TESTS UNDER NACL ENVIRONMENT

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ashok Kumar M ◽  
Thirumalaikumarasamy D ◽  
Paventhan R ◽  
Thirumal P
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Welding Process ◽  
Ion Concentration ◽  
Az31b Magnesium Alloy ◽  
Corrosion Tests ◽  
Friction Stir ◽  
Corrosion Rates

An investigation was carried out to quantify and characterize the corrosion behaviour of AZ31B magnesium alloy joints. Extruded Mg alloy plates of 6 mm thick of AZ31B grade were butt welded using a solid state, environmentally cleaner welding process, friction stir welding process. The weld specimens were underwent immersion, salt spray, pitting and galvanic corrosion tests in order to quantify and characterize the corrosion rates of the welds with the influence of different pH values, chloride ion concentration and the corrosion time. The corrosion rates, microstructure, scanning electron microscopy and X-ray diffraction analysis concludes the optimum parameter for the usage of the magnesium alloy welds for the best service applications. Keywords: Keywords: EDM, Alumina and Genetic Algorithm

Effect of Ni Alloying on the Corrosion Resistance of 355MPa High Weather-Resistant Steel

2015 ◽  
Vol 816 ◽  
pp. 781-787
Author(s):  
Z.R. Hou ◽  
H.L. Yi ◽  
X.M. Zhao
Keyword(s):  
Corrosion Resistance ◽  
Weathering Steel ◽  
Resistant Steel ◽  
Rust Layer ◽  
Corrosion Tests ◽  
Ni Content

Based on the 355MPa high weather-resistant steel, three different kinds of high weather-resistant steels were designed by varying the content of Ni. The the corrosion resistance of the high weather-resistant steel as well as the influence of Ni content on the corrosion resistance were studied in the present investigation. The results of the cycle corrosion tests indicated that with the addition of Ni, the corrosion resistance was improved to some extent. The rust layer of the weathering steel was composed of α-FeOOH and γ-FeOOH at the beginning of corrosion, and the α-FeOOH turned to γ-FeOOH which enhanced the corrosion resistance.

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