Assessment of corrosion resistance of surface-coated galvanized steel by analysis of the AC impedance spectra measured on the salt-spray-tested specimen

2006 ◽  
Vol 11 (6) ◽  
pp. 829-839 ◽  
Author(s):  
Sung-Jai Lee ◽  
Su-Il Pyun
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Ac Impedance ◽  
Galvanized Steel ◽  
Impedance Spectra ◽  
Ac Impedance Spectra

scholarly journals Corrosion Behaviour of Metals in Artificial Tear Solution

2016 ◽  
Vol 8 (3) ◽  
pp. 1716-1735
Author(s):  
C. Kumar ◽  
A. John Amal Raj ◽  
S.K. Selvaraj
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
Corrosion Behaviour ◽  
Ac Impedance ◽  
Impedance Spectra ◽  
Artificial Tear ◽  
Polarization Study ◽  
Ac Impedance Spectra

Human tear comes in contact with a number of instruments during operation in the eyes.  This results in a variety of undesirable effects such as corrosion and malfunction.  Corrosion behaviour of five metals, namely, mild steel (MS), mild steel coated with zinc (MS-Zn), Ni-Cr, Ni-Ti super elastic (Ni-Ti.SE), and SS 316 L in artificial tear solution has been studied by polarization study and AC impedance spectra.  The study reveals that the decreasing order of corrosion resistance in artificial tear solution is : Ni-Ti SE > Ni-Cr > SS 316 L > MS-Zn > MS.  The first three metals are better candidates and the first one is the best candidate for making instruments used in operation in the eyes, in presence of tears.

scholarly journals Inhibition of corrosion of SS 18/8 alloy is sea water by Thiourea-Zn2+ system

2021 ◽  
Vol 62 (3) ◽  
pp. 191-203
Author(s):  
Josephath Praveena ◽  
Somasundaram Gowri ◽  
Gunasekaran Nethravathi ◽  
Vincent Varsha ◽  
Arockiasamy Vieyana ◽  
...  
Keyword(s):  
Weight Loss ◽  
Corrosion Resistance ◽  
Metal Surface ◽  
Sea Water ◽  
Ac Impedance ◽  
Protective Film ◽  
Impedance Spectra ◽  
Weight Loss Method ◽  
Loss Method ◽  
Ac Impedance Spectra

The corrosion resistance of SS 18/8 in natural sea water, in presence of an inhibitor named Thiourea-Zn2+ has been evaluated. Weight loss method, polarization study and AC impedance spectra have been employed to evaluate the corrosion resistance of SS 18/8 alloy in natural sea water, in presence of an inhibitor named Thiourea-Zn2+ system. Weight loss method reveals that Thiourea-Zn2+ system offers a maximum corrosion inhibition efficiency of 95% in controlling corrosion of SS 18/8 alloy in natural sea water. Synergism parameters are found to be greater than 1, confirming the synergistic effect existing between Thiourea-Zn2+. Adsorption of inhibitor molecules on the metal surface obey Langmuir adsorption isotherm. Polarisation study reveals that the inhibitors named Thiourea-Zn2+ system functions as mixed type of inhibitor. AC impedance spectra confirm the formation of a protective film on the metal surface. This formulation of Thiourea-Zn2+ may be used in cooling water systems where SS 18/8 alloy pipelines are used to carry sea water which is used as coolant. Also, Thiourea-Zn2+ coating can be given on SS 18/8 alloy to protect it from corrosion by sea water when SS 18/8 alloy is used as hull plates in ship industry.

Research to the Corrosion Resistance of the Alkaline Zinc-Nickel Alloy Plates

2012 ◽  
Vol 616-618 ◽  
pp. 1756-1761
Author(s):  
He Zhong Pei ◽  
Pan Huang ◽  
Qing Nan Shi ◽  
Guo Liang Zhang ◽  
Xue Li
Keyword(s):  
Corrosion Resistance ◽  
Nickel Alloy ◽  
Salt Spray ◽  
Nickel Content ◽  
Neutral Salt ◽  
Impedance Spectra ◽  
Plating Bath ◽  
Corrosion Reaction ◽  
Ac Impedance Spectra ◽  
Zinc Nickel

The zinc-nickel alloy coatings were electrodeposited by changing the concentration of the NiSO4 • 6H2O in the plating bath. The scanning electron microscopy (SEM) was used to observe the coating’s surface morphology. The EDS was applied to test the coating’s nickel content. The corrosion resistance was studied by using the Tafel curves, AC impedance spectra and the neutral salt spray test. The results showed that: The coating’s nickel content could reach 12.56% when the NiSO4 • 6H2O concentration was 8g/L in the bath and the coating was very smooth, dense and bright. Its corrosion potential was low and its corrosion reaction resistance was best with red rust time up to 46d, so it had good corrosion resistance. But when the NiSO4 • 6H2O concentration was changed, the coatings’ corrosion resistance would be more or less changed.

AC Impedance Spectra Arising from Mixed Ionic Electronic Solid Electrolytes

2004 ◽  
Vol 151 (5) ◽  
pp. E186 ◽  
Author(s):  
Alan Atkinson ◽  
Sylvia A. Baron ◽  
Nigel P. Brandon
Keyword(s):  
Solid Electrolytes ◽  
Ac Impedance ◽  
Impedance Spectra ◽  
Ac Impedance Spectra

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%.

INVESTIGATIONS ON THE ELECTRICAL PROPERTIES OF ZnO NANORODS AND COMPOSITES FOR PHOTOVOLTAIC AND ELECTROCHEMICAL APPLICATIONS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 81-85 ◽  
Author(s):  
PARAMESWAR HARI ◽  
MICHAL BYRCZEK ◽  
DALE TEETERS ◽  
PRAVIN UTEKAR
Keyword(s):  
Polyethylene Oxide ◽  
Indium Tin Oxide ◽  
Zno Nanorods ◽  
Ac Impedance ◽  
Zno Films ◽  
Zno Nanorod ◽  
Impedance Spectra ◽  
Atomic Force ◽  
Ac Impedance Spectra ◽  
Zno Rods

ZnO nanorods grown by hydrothermal technique on glass, Zinc, and Indium tin oxide (ITO) substrates exhibit both open and closed hexagonal structures. On the nanoscale, closed ZnO nanostructures exhibit two types of ion conduction regions as revealed by AC-impedance spectra collected through the tip of an atomic force microscope (AFM). One region has higher impedance values (apparent values of approximately 107 ohms) with two semicircles. Two semicircles are indicative of a ZnO structure composed of bulk and grain boundary conduction. Other regions were found to have impedance values that were two orders of magnitude lower (apparent values of 105 ohms). This indicates that these ZnO films have two conduction pathways. The polyethylene oxide ( PEO )– ZnO nanorod composite was made by spin-coating the ZnO rods growing from the ITO substrate with PEO. In the PEO – ZnO composite film, only the AC impedance values of 105 ohms were observed. This is higher than PEO electrolyte without ZnO nanorods. Since regions of higher impedance were not seen in the PEO – ZnO nanorod composites, the polymer electrolyte either dominated the conduction of the system or suppressed the first pathway of higher impedance in the ZnO rods.

Passivation Effect of Rare Earth Lanthanum on Galvanized Steel

2014 ◽  
Vol 525 ◽  
pp. 31-34
Author(s):  
Xiao Feng Liu
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Electrochemical Impedance ◽  
Orthogonal Experiment ◽  
Salt Spray ◽  
Conversion Coating ◽  
Galvanized Steel ◽  
Neutral Salt ◽  
White Rust ◽  
Order Of Magnitude

By way of chemical marinate method, carrying out rare earth lanthanum to corrosion protect galvanized steel. The process of rare earth lanthanum conversion coating for galvanized steel was studied by using orthogonal experiment to get the optimized passivation parameters when the concentration of La (NO3) is 30g/L, H2O2is 20ml/L, pH=4 and was passivated at 40°C for 30s. The corrosion resistance was examined by weight loss tests, neutral salt spray tests (NSS) and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion impedance of the pretreated sample was significantly improved, the corrosion rate was decreased by one order of magnitude, and the anti-white rust time was 54h.

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