scholarly journals The Corrosion Performance of Galvanized Steel in Closed Rusty Seawater

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shuan Liu ◽  
Huyuan Sun ◽  
Ning Zhang ◽  
Lijuan Sun
Keyword(s):  
Hydrostatic Pressure ◽  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Chemical Characterization ◽  
Galvanized Steel ◽  
Corrosion Performance ◽  
Rust Layer ◽  
Tafel Polarization ◽  
Effects Of Temperature

The corrosion performance of galvanized steel in closed rusty seawater (CRS) was investigated using weight loss, Tafel polarization curve, and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were carried out for morphological and chemical characterization of the rust layer absorbed on the zinc coating. Effects of temperature and hydrostatic pressure on corrosion resistance of galvanized steel were studied. Results indicated that rust layer could induce pitting corrosion on the zinc coating under the Cl−erosion; high temperature accelerated the corrosion rate of zinc coating and inhibited the absorption of rust layer; the polarization resistance (Rp) of galvanized steel increased with the increase of hydrostatic pressure in CRS.

Study of Corrosion Behaviour of Molybdenum Series Coatings on Galvanized Steel

2011 ◽  
Vol 399-401 ◽  
pp. 1972-1975 ◽  
Author(s):  
Hui Min Zhang ◽  
Lin Wu ◽  
Zhao Hui Ouyang ◽  
De Lian Yi ◽  
Qiao Hua ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Acrylic Resin ◽  
Galvanized Steel ◽  
Coupling Agents ◽  
Neutral Salt ◽  
Tafel Polarization ◽  
Chromate Coating

In this paper, an organic/inorganic molybdenum series Cr-free coating was formed on galvanized steel by simple immersion and its corrosion behavior was compared to that of a typical chromate coating. Molybdate and 1-Hydroxy-ethylidene-1, 1-diphosphonic acid (HEDP) were used as corrosion inhibitor, as well as acrylic resin and silane were used as film-former and coupling agents, respectively. The corrosion behavior of the coatings was evaluated by Neutral salt spray (NSS), Electrochemical impedance spectroscopy (EIS) and Tafel polarization. The surface topography of the samples was observed by Scanning Electron Microscopy (SEM). The results indicated that the corroded area of the Mo-HEDP treatment was only corroded 2% after 72 h spraying, while the corrosion behaviour of Mo-HEDP was closed to that of Cr pretreatment due to the synergistic reaction of molybdate and HEDP. Compared with the film of Cr treatment, Mo-HEDP passivating coating was more environmentally friendly.

Corrosion Characteristics of 16Mn and Q235B Steel in Natural Seawater

2012 ◽  
Vol 591-593 ◽  
pp. 1046-1049
Author(s):  
Yong Liu ◽  
Xing Hua Tong ◽  
Bao Guo Li ◽  
Yan Gang Wang ◽  
Lin Sen Zhu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Method ◽  
Electrochemical Impedance ◽  
Corrosion Process ◽  
Polarization Curves ◽  
Natural Seawater ◽  
Rust Layer ◽  
Tafel Polarization ◽  
Corrosion Electrochemical Behavior

In order to study the corrosion characteristics of 16Mn and Q235B steel in natural seawater, the indoor contrast corrosion experiments are carried out in seawater by electrochemical method. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of 16Mn and Q235B steel, which are acquired by electrochemical workstation. The results of polarization curves and EIS reveal the respective corrosion rules of 16Mn and Q235B steel in natural seawater. At last, the different influence of rust layer on the corrosion process of 16Mn and Q235B steel is analyzed contrastively.

THE ELECTROCHEMICAL BEHAVIOR OF DOPED SILANE PRE-TREATMENTS ON GALVANIZED STEEL SUBSTRATES

2017 ◽  
Vol 24 (02) ◽  
pp. 1750015
Author(s):  
QILIANG ZHAO ◽  
WEI GUO ◽  
QINGDONG ZHONG ◽  
JUNLIANG ZHANG ◽  
JINHU SUN ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Barrier Properties ◽  
Galvanized Steel ◽  
Dynamic Polarization ◽  
Corrosion Performance ◽  
Surface Microstructures ◽  
Steel Substrates ◽  
Inhibition Ability ◽  
Silane Layer ◽  
Trimethoxy Silane

In this paper, galvanized steel substrates were pre-treated in [Formula: see text]-(2,3-epoxypropoxy)propyl trimethoxy silane solutions containing salts ((NH[Formula: see text]TiF6, K2ZrF6 and NaVO[Formula: see text] and SiO2. The surface microstructures of the coated substrates were evaluated by scanning electron microscopy (SEM). The anti-corrosion performance of the modified silane film applied on galvanized steel substrates was evaluated by potentio-dynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). The electrochemical results reveal that the addition of salts ((NH[Formula: see text]TiF6, K2ZrF6 and NaVO[Formula: see text] may produce a more stable and protective fluoride combined with their oxides in the silane layer. The results also reveal that the addition of the SiO2 nanoparticles reinforced the barrier properties of the silane films and imparted its corrosion inhibition ability.

Corrosion Protection of Molybdenum-Phosphorus Compounds Based Coating Formed on Hot Dip Galvanized Steel in a Cl- Ione Environment

2013 ◽  
Vol 750-752 ◽  
pp. 2017-2020
Author(s):  
Wan Qiu Zhou ◽  
Yan Rong Liu ◽  
Jian Wang ◽  
Li Sheng ◽  
Shi Wei Wu ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Conversion Coating ◽  
Galvanized Steel ◽  
Phosphorus Compounds ◽  
Electrochemical Technique ◽  
Corrosion Performance ◽  
Addition Agent ◽  
X Ray ◽  
Ph Decrease ◽  
Surface Morphologies

Molybdate-phosphate conversion coating was prepared by adding addition agent towards molybdenum-phosphorus compounds based bath on comercial hot dip galvanized steel. The anti-corrosion performance of the coating was evaluated by electrochemical technique in 3.5%NaCl. It is found that the anodic branch of polarization curves presented in passivation character. Electrochemical impedance spectroscopy (EIS) results indicate that the radius of the capacity impedance for molybdate-phosphate film increased distinctly with pH decrease, which validate the excellent anti-corrosion performance of the film. The surface morphologies were observed using scanning electron microscopy (SEM), and the results show that the surface of hot dip galvanized steel is covered by a spiculate and floccule shape conversion coating. The chemical composition of the surface coating was investigated by energy dispersive X-ray (EDX), which illustrate that the conversion coating is composed of zinc,oxygen, phosphor and molybdenum.

Corrosion Performance Study of Anodic Film Formed by Oxidizing Magnesium Alloy in Environmentally Friendly Electrolyte

2011 ◽  
Vol 686 ◽  
pp. 17-20 ◽  
Author(s):  
Ding Fei Zhang ◽  
Li Bo Cui ◽  
Yu Ping Liu
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrical Circuit ◽  
Polarization Curves ◽  
Anodic Film ◽  
Equivalent Electrical Circuit ◽  
Optimum Temperature ◽  
Corrosion Performance ◽  
Performance Study ◽  
Tafel Polarization

The effect of different factors on the corrosion performance of the anodic film formed on AZ31 was studied by using electrochemical impedance spectroscopy (EIS) and Tafel polarization curves techniques. The result of EIS showed that the oxide film formed at 20 mA·cm-2had the highest corrosion resistance and the optimum temperature was 40°C. The similar conclusion was drawn by the Tafel polarization curves. Moreover, the equivalent electrical circuit R(C(R (QR))) (CR) was used to analyze the EIS data.

Mechanical and Chemical Characterization of Hard Anodized Cooker Grids Made in Al-Si Alloy

2019 ◽  
Vol 813 ◽  
pp. 334-339
Author(s):  
Fabio Scherillo ◽  
Vincenza Marzocchi ◽  
Antonino Squillace ◽  
Eugenio Amendola
Keyword(s):  
Detrimental Effect ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Chemical Characterization ◽  
Commercially Pure ◽  
Alloy Microstructure ◽  
A Current ◽  
Made In

In the present work the performances of hard anodized component in Al-Si alloy, used as cooker grids, are described in details. The components have been anodized in H2SO4 at low temperature (less than 0 °C) with a current of about 2.4/dm2 A for 70 min.The effect of the alloy microstructure on the quality of the anodized layer is evidentiated, particularly the Si rich intermetallics inside the metal have a detrimental effect on the performance of the oxidized layer.The components have been analyzed by means of nano-indentation to evaluate the mechanical behavior of the layer. The chemical performances have been studied using Electrochemical Impedance Spectroscopy in different solutions (0.05 M Na2SO4 and 0.01 M NaOH). The results obtained have been correlated with the microstructure of the alloy, furthermore all test have been done, for comparison, on Commercially Pure Aluminum anodized in the same conditions of the Al-Si components.The results indicate that the mechanical properties of the anodized layer of Al-Si components are lower to respect that of Commercially Pure Aluminum.On the contrary the chemical resistance of Al-Si anodized items result poor compared to Commercially Pure Aluminum, in particular the oxidized layer is subject to degradations due to the presence of Si rich inclusions.

Preparation and Corrosion Behavior of Environment Friendly Conversion Coating Formed on Zn-5%Al Galvanized Steel

2013 ◽  
Vol 773 ◽  
pp. 429-434
Author(s):  
Wan Qiu Zhou ◽  
Jian Wang ◽  
Li Sheng ◽  
Yan Hong Kang ◽  
Shi Gang Xin ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Preparation Condition ◽  
Conversion Coating ◽  
Galvanized Steel ◽  
Electrochemical Technique ◽  
Corrosion Performance ◽  
Environment Friendly ◽  
X Ray ◽  
Preparation Conditions ◽  
Chromate Conversion Coating

A non-chromate conversion coating was prepared from molybdate based bath on the surface of Zn-5%Al hot dip galvanized steel. The influence of the preparation conditions such as temperature, bath pH and treating time on the corrosion resistance of the obtained conversion coating was investigated. The corrosion performance of the film was researched using electrochemical technique in 3.5%NaCl. The results indicate that the anodic branch of the polarization curves present in passivation character. Electrochemical impedance spectroscopy (EIS) illustrate that the radius of the capacity impedance for conversion coating varies distinctly according to the preparation condition. The surface morphology was observed using scanning electron microscopy (SEM), and the results show that the surface of Zn-5%Al hot dip galvanized steel present in eutectic feature after conversion coating treatment. The chemical composition of the coating was detected by energy dispersive X-ray (EDX), and the results illustrate that the conversion coating is composed of Zn, Al , O, P and Mo.

scholarly journals A Two-Year Evaluation of Corrosion-Induced Damage to Hot Galvanized Reinforcing Steel B500SP in Chloride Contaminated Concrete

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3315
Author(s):  
Mariusz Jaśniok ◽  
Maria Sozańska ◽  
Jacek Kołodziej ◽  
Bartosz Chmiela
Keyword(s):  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Reference Electrode ◽  
Chloride Content ◽  
Corrosion Current ◽  
Galvanized Steel ◽  
Reinforcing Steel ◽  
Low Carbon ◽  
High Concentration ◽  
Test Elements

Corrosion-induced damage to concrete reinforced with bars is a serious problem regarding technical and economic aspects and strongly depends on used materials, corrosion environment, and service life. Tests described in this paper refer to a two-year evaluation of the effectiveness of protection provided by zinc-coated low-carbon reinforcing steel of grade B500SP in concrete against chloride corrosion. Performed tests were comparative and included measurements conducted on four groups of concrete test elements with dimensions of 40 mm × 40 mm × 140 mm reinforced with a bar having a diameter of ϕ8 mm. Particular groups were a combination of different types of concrete with or without chloride additives, with galvanized or black steel. Chlorides as CaCl2 were added to the concrete mix in the amount of 3% of cement weight in concrete. Reinforced concrete specimens were periodically monitored within two years using the following techniques: linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Polarization measurements were conducted in a three-electrode arrangement, in which a rebar in concrete served as a working electrode, stainless steel sheet was used as an auxiliary electrode, and Cl−/AgCl,Ag was a reference electrode. Comparative tests of changes in the density of corrosion current in concrete specimens without chloride additives basically demonstrated no development of corrosion, and possible passivation was expected in case of black steel. Higher densities of corrosion current were observed for galvanized steel during first days of testing. The reason was the dissolution of zinc after the contact with initially high pH of concrete pore solution. Six-month measurements demonstrated a higher density of corrosion current in concrete specimens with high concentration of chlorides, which unambiguously indicated corrosion in concrete reinforced with galvanized or black steel. Densities of corrosion current determined for selected specimens dramatically decreased after an 18-month interval in measurements. Corrosion was even inhibited on black steel as an insulating barrier of corrosion products was formed. The above observations were confirmed with structural studies using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. Results obtained from corrosion (LPR, EIS) and structural (SEM, EDS) tests on specimens of concrete reinforced with steel B500SP demonstrated a very favorable impact of zinc coating on steel by providing two-year protection against corrosion in the environment with very high chloride content.

Effect of under layer metallic coating composition on phosphating and the corrosion performance for automobile applications

CORROSION ◽  
10.5006/3748 ◽  
2021 ◽  
Author(s):  
Chandrashekhar Savant ◽  
Poorwa Gore ◽  
VS Raja
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Organic Coating ◽  
Phosphate Coating ◽  
Corrosion Performance ◽  
Epoxy Primer ◽  
Phosphate Coatings ◽  
Galvanized Coating ◽  
Salt Fog

Automobile coating system consists of a metallic underlayer followed by a phosphate coating and, lastly, multilayer organic coating. In this work, the effect of the underlying metallic coatings, namely, a Mg-Al-Zn alloy coating (Magizinc) and a conventional galvanized Zn coating on the phosphate coatings formed thereon, and its corrosion performance was investigated. The corrosion resistance offered by the phosphate coating formed on the Magizinc coating was higher than the phosphate coating on the galvanized Zn coating (a reference coating employed in the study) in NaCl solution, as revealed by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt-fog tests. In-depth characterization of the phosphate coatings was carried out using scanning electron microscopy and glow discharge optical emission spectroscopy. It was revealed that the phosphate crystals formed on the Magizinc coating were more fine-grained, compact, and crack-free as compared to that formed on the galvanized coating and contained Mg aiding 4-10 times increase in the corrosion resistance as determined by the electrochemical studies. However, it only improved marginally against the appearance of red rust in a salt-fog test over the unphosphated Magizinc coating. The phosphate coating on Magizinc marginally improved the adhesion of an epoxy primer coating applied on the phosphated Magizinc coating and significantly (>3.5 times longer exposure) retarded the deterioration of the epoxy primer coating in the salt-fog environment in comparison with the similar studies carried out on the phosphated conventional galvanized zinc coating. Notably, phosphating the Magizinc coating caused a ten times reduction in the H pickup compared to that in the galvanized coating under identical phosphating conditions, suggesting the former coating lowered the propensity for hydrogen embrittlement in the steel.

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