scholarly journals The relationship between surface treatments and corrosion resistance of hot-dip galvanized steel

2014 ◽  
Vol 20 (3) ◽  
pp. 165-170 ◽  
Author(s):  
Amirreza Bakhtiari
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Surface Treatments ◽  
Galvanized Steel ◽  
Tafel Polarization ◽  
Galvanized Coatings ◽  
The Relationship ◽  
Scanning Electron ◽  
Resistance Difference

In this work three surface treatments such as: polishing, sand-blast and polishedoxidized have been carried out on the hot-dip galvanized coatings. The roughness and corrosion resistance of coatings have been studied. Surface morphology of coatings has evaluated by scanning electron microscope (SEM). Corrosion behavior was analyzed by salt spray cabinet test and Tafel extrapolation test. The results showed that the sample under sand-blasted treatment exhibited the highest roughness number. Tafel polarization and salt spray cabinet tests reveal the sample with great roughness number have weak corrosion resistance. Difference observed in corrosion behaviour can be explained by difference in surface roughness.

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 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.

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.

Research of Organic/Inorganic Chromium-Free Co-Passivation Treatments for Galvanized Steel

2013 ◽  
Vol 785-786 ◽  
pp. 881-886
Author(s):  
Qi Pan ◽  
Lin Wu ◽  
De Lian Yi ◽  
Zhao Hui ◽  
Ou Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Composite Film ◽  
Salt Spray ◽  
Galvanized Steel ◽  
Neutral Salt ◽  
Ac Impedance Spectroscopy ◽  
Good Adhesion ◽  
Passivation Film ◽  
Tafel Polarization ◽  
Inorganic And Organic

The corrosion resistance of chromium-free passivation film with single chromate-free passivation solution to deal with galvanized steel still has a gap compared to chromate passivation. In this experiment, the passivation solution consisting of the inorganic salt as corrosion inhibitor, silane as sealer, water-based epoxy resin and additives which formed a layer of inorganic and organic composite passivation film on galvanized steel through the synergistic effect between inorganic and organic. The morphology and elements of the passivation film was analyzed by scanning electron microscopy (SEM) and the corrosion resistance of the composite film was tested by neutral salt spray test (NSS), lead acetate spot test (ASS), tafel polarization curves and AC impedance spectroscopy (EIS). The results show that the composite film has a good adhesion and an excellent corrosion resistance, the corrosion area is only 3% after 72h NSS.

The Study of Electroless Ni-P and Ni-P-PTFE Coating on Steel Tire Mold

2012 ◽  
Vol 501 ◽  
pp. 316-320
Author(s):  
Jian Zhang Guo ◽  
Bin Xu
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Pore Structure ◽  
Energy Dispersive Spectrometer ◽  
Salt Spray ◽  
Amorphous Structure ◽  
Carbon Steels ◽  
Electrochemical System ◽  
Electroless Ni ◽  
Scanning Electron

In order to improve the surface property of the steel tire mold, carbon steels were processed by electroless Ni-P and Ni-P-PTFE under contrast experiment. The coatings were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). The wear resistance and corrosion resistance of the coatings were explored by tribometer, salt spray cabinet and advanced electrochemical system. The experimental results showed that the Ni-P coating was amorphous structure, and the Ni-P-PTFE coating was micro-pore structure; The wear resistance of Ni-P-PTFE coating was superior to Ni-P coating; In view of the micro-pore structure, the corrosion resistance of Ni-P-PTFE coating was worse than Ni-P coating, but they were all superior to carbon steels, and the service life of the steel tire mold were improved.

scholarly journals Effect of Additives on Electrodeposition of Zinc-Nickel Alloy On Mild Steel

2019 ◽  
Vol 31 (4) ◽  
pp. 891-895
Author(s):  
Dinesh Kumar Chelike ◽  
K. Juliet Gnana Sundari
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Alloy Coating ◽  
Complexing Agent ◽  
Tafel Polarization ◽  
Good Corrosion Resistance ◽  
Ni Alloy ◽  
Strong Candidate

Considering the good corrosion resistance of Zn-Ni alloy, it is selected in the present study to be the protective coating on mild steel and it is considered as a strong candidate for the replacement of environmentally hazardous cadmium. Zn-Ni alloy coating is applied by electrodeposition at optimum temperature, current density and time. The bath solution used is consisting of EDTA as complexing agent. The electrodeposition is also carried out with tartaric acid and benzaldehyde additives to have good corrosion resistance and brightness. The electrodeposits obtained with and without additives are examined for nature and alloy composition. The corrosion behaviour of the electrodeposits is studied by Tafel polarization and electrochemical impedance spectroscopy.

The Study of Electroless Ni-B Coating on 45 Steel

2012 ◽  
Vol 501 ◽  
pp. 185-189
Author(s):  
Jian Zhang Guo ◽  
Qian Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Energy Dispersive Spectrometer ◽  
Salt Spray ◽  
High Hardness ◽  
Experimental Results ◽  
Electroless Ni ◽  
Scanning Electron ◽  
Optimal Formula

In order to improve the corrosion resistance and the hardness of the 45 steel, under comparison tests, the electroless Ni-B was prepared on the 45 steel. We made a contrast test to get the optimal formula. The coating under the optimal formula was characterized by Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometer(EDS), metallurgical microscope and salt spray cabinet. The experimental results showed that the electroless Ni-B coating on 45 steel was low boron coating, with high hardness, and the hardness of the coating could catch HV524; the thickness of the coating was 16μm.

Corrosion Behaviour of AZ91DSm1.0 with Different Preparation Methods

2014 ◽  
Vol 1004-1005 ◽  
pp. 113-118
Author(s):  
Hong Xia Liu ◽  
Jin Liang ◽  
Jue Zhang ◽  
Xiao Lian Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
X Ray Diffraction ◽  
Vacuum Melting ◽  
Potentiodynamic Polarization Curve ◽  
Preparation Methods ◽  
X Ray ◽  
Scanning Electron

Corrosion behaviour of AZ91DSm1.0 with different preparation methods(vacuum melting and common melting) is investigated. X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), corrosion weightless experiment and the potentiodynamic polarization curve are applied to characterize the corrosion behaviour. Results show that vacuum melting alloy possess higher corrosion resistance than common melting alloy. This is attributed to the rod-shaped Al3Sm which was formed in common melting alloy will have certain fragmentation effect on matrix that can lead to defects.

scholarly journals Corrosion Behaviour of Zn-10Al-1.5Cu Alloy

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
C. N. Panagopoulos ◽  
A. G. Tsopani
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Solution Concentration ◽  
Solution Temperature ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nacl Concentration ◽  
Scanning Electron

The corrosion behaviour of Zn-10Al-1.5Cu alloy in NaCl solution was examined. The used NaCl solution concentrations were 1M, 0.3M, and 0.003M for a constant temperature values of 7°C or 25°C or 45°C. The corrosion behaviour of this alloy was investigated under potentiodynamic corrosion conditions. The surface of the corroded alloy specimens was studied with the aid of scanning electron microscopy and X-ray diffraction techniques. It was observed that the increase of NaCl concentration in the corrosion solution for a constant value of temperature led to lower corrosion resistance of the alloy. For a constant value of solution concentration, the increase of solution temperature also led to the decrease of corrosion resistance of the same alloy.

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.

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