Application of EIS and SEM to Study the Corrosion Behaviors of Organic Coatings/Substrate System

2008 ◽  
Vol 373-374 ◽  
pp. 556-559 ◽  
Author(s):  
Rui Yan ◽  
Hang Wu ◽  
S.K. Yu ◽  
Shi Ning Ma ◽  
Bin Shi Xu
Keyword(s):  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Electrochemical Corrosion ◽  
Metal Substrate ◽  
Open Circuit ◽  
Free Corrosion Potential ◽  
Cross Linkage ◽  
Sem Micrograph ◽  
Corrosion Behaviors

Electrochemical corrosion behaviors of two common-used ship coatings——epoxy aluminum coating, chloride rubber iron red coating and their composite coatings immersed in 3.5%NaCl solution were investigated using electrochemical impedance spectroscopy combined with open circuit potential measurements and SEM micrograph analysis. Potential-time result indicates that the free corrosion potential of these three coatings with immersion time are more positive than that of metal substrate, which can serve as barrier layer to protect metal substrate from corrosion. During the course of immersion, increasingly negative shift potentials with time reveal the growth of electrochemical area of anode and corrosion takes place continuously. EIS shows that corrosive species can penetrate into coatings and reach the coating/substrate interface promptly, causing the decrease of its shielding role and the beginning of electrochemical corrosion. SEM micrographs suggest that coatings were compact and continuous compared with obviously coarse and loose after corrosion, indicating the penetration of corrosive species destroys cross linkage of coatings. Composite coatings present better protection performance, displaying the effect of “1+1>2” remarkably.

Electrochemical Behaviors of Die-Cast Mg-4Al-0.4Mn-Xpr (x=0, 1, 4) Alloys in NaCl Solution

2013 ◽  
Vol 690-693 ◽  
pp. 82-88
Author(s):  
Xiao Dong Niu ◽  
Wei Sun ◽  
Xin Qiu ◽  
Jian Meng ◽  
Jian An
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Nacl Solution ◽  
Electrochemical Behaviors ◽  
Β Phase ◽  
Die Cast ◽  
Corrosion Behaviors ◽  
Potential Test

The microstructures and electrochemical corrosion behaviors of die-cast Mg-4Al-0.4Mn-xPr (x=0, 1, 4 wt.%) alloys have been investigated. Electrochemical behaviors of all alloys are described by open circuit potential test, potentiodynamic polarization test and electrochemical impedance spectroscope in 3.5 wt.% NaCl solution. The results show that the α-Mg grain is refined and the continuous net β phase appears gradually with increasing the content of Pr in the Mg-4Al-0.4Mn alloys. Moreover, the β phase plays a role of galvanic cathode in AM40 alloy and corrosion barrier in Pr-containing alloys, respectively. Electrochemical measurements show that Pr can improve corrosion resistance of Mg-4Al-0.4Mn alloy in the 3.5 wt.% NaCl solution, and corrosion rate decreases with increasing Pr content.

scholarly journals Effect of Cu Addition on the Electrochemical Corrosion Performance of Ni3Al in 1.0 M H2SO4

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodriguez-Diaz ◽  
E. Porcayo-Palafox ◽  
J. Colin ◽  
A. Molina-Ocampo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Intermetallic Alloy ◽  
Intermetallic Alloys ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Electrochemical Corrosion Behavior

The effect of Cu addition on the electrochemical corrosion behavior of Ni3Al intermetallic alloy was investigated by potentiodynamic polarization, open-circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy in 1.0 M H2SO4solution. Performance of the pure elements (Cu, Ni, and Al) was also evaluated. In general, Cu addition improved the corrosion resistance of Ni3Al. Electrochemical measurements show that corrosion resistance of Ni3Al-1Cu alloy is lower than that of other intermetallic alloys and pure elements (Ni, Cu, and Al) in 1.0 M H2SO4solution at 25°C. Surface analysis showed that the Ni3Al alloys are attacked mainly through the dendritic phases, and Cu addition suppresses the density of dendritic phases.

Corrosion Behavior of 10CrNiCu Steel Influenced by Thiobacillus Ferrooxidans

2011 ◽  
Vol 233-235 ◽  
pp. 2633-2639
Author(s):  
Kyaw Soe ◽  
Song Mei Li ◽  
Jian Hua Liu ◽  
Mei Yu
Keyword(s):  
Open Circuit Potential ◽  
Thiobacillus Ferrooxidans ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Analysis Method ◽  
Microbial Corrosion ◽  
Solution Interface ◽  
Sterile Medium ◽  
Corrosion Behaviors ◽  
Surface Analysis Method

The microbial corrosion behaviors of 10CrNiCu steel influenced by Thiobcillus ferrooxidans (T.f) were studied by microbiological, electrochemical and surface analysis method. The open circuit potential (Eocp) and electrochemical impedance spectroscopy (EIS) of the 10CrNiCu electrodes were measured in immersion electrode way with and without T.f solution at the time of the 0, 2nd, 7th, 14thand 21stdays, respectively. Eocpof the electrode immersed in sterile medium shifted to negative potential with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. EIS results were interpreted with different equivalent circuits of the electrode/biofilm/solution interface. The result of SEM indicated that, after 21 immersion days, there were different sizes of pits on the 10CrNiCu surface occurred in T.f solution while no evidence of the pitting corrosion was observed on the steel surface immersed in the sterile medium.

Electrochemical corrosion behavior of HVOF sprayed WC–12Co coating on H13 hot work mould steel

2019 ◽  
Vol 66 (6) ◽  
pp. 827-834
Author(s):  
Kong Weicheng ◽  
Shen Hui ◽  
Gao Jiaxu ◽  
Wu Jie ◽  
Lu Yuling
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Curvature Radius ◽  
Nacl Solution ◽  
Content Type ◽  
Capacitance Curve ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors

Purpose This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a guiding significance on the corrosion resistance of H13 hot work mould steel. Design/methodology/approach A WC–12Co coating was fabricated on H13 hot work mould steel using a HVOF, and the electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution was measured using open circuit potential (OCP), potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) tests. Findings The OCP and PPC of WC–12Co coating positively shift than those of substrate, its corrosion tendency and corrosion rate decrease to enhance its corrosion resistance. The curvature radius of capacitance curve on the WC–12Co coating is larger than that on the substrate, and the impedance and polarization resistance of WC–12Co coating increase faster than those of substrate, which reduces the corrosion process. Originality/value The electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution is first measured using OCP, PPC and EIS tests, which improve the electrochemical corrosion resistance of H13 hot work mould steel.

Electrochemical Behavior of Potassium Zinc Phosphates Extract and Coating

2012 ◽  
Vol 152-154 ◽  
pp. 64-67 ◽  
Author(s):  
Dong Ping Wei ◽  
Shao Mei Ma ◽  
Ze Guang Zhou ◽  
Zeng Wei Huang ◽  
Ai Qun Yuan ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Corrosive Medium ◽  
Open Circuit Potential ◽  
Zinc Phosphate ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Immersion Test ◽  
Open Circuit ◽  
Zinc Phosphates ◽  
Pigment Extract

The electrochemical corrosion inhibitions of potassium zinc phosphate were studied by polarization, open circuit potential measurements, electrochemical impedance of the pigment extract and coating immersion test. Dynamic analysis shows that in pH=7 3.5% NaCl extract, KZn2(PO4)(HPO4) functions as a cathodic inhibitor on steel and its efficiency is even superior to other phosphates. The inhibiting efficiency of the pigments on steel decrease in the order: KZn2(PO4)(HPO4) > aluminum zinc phosphate > zinc phosphate ≧ aluminum triphosphate The coating tests show that potassium zinc phosphate can efficiently enhance the inhibition properties of coating and prevent the erosion of the corrosive medium by improving the barrier and hydrophobicity of the coating. The anticorrosive property of the pigments decrease in the order: KZn2(PO4)(HPO4)> aluminum zinc phosphate > zinc phosphate ≈APW-1.

scholarly journals Preparation of Coating on the Titanium Surface by Micro-Arc Oxidation to Improve Corrosion Resistance

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 230 ◽  
Author(s):  
Yulong Hu ◽  
Zhiqiao Wang ◽  
Jianyang Ai ◽  
Shichao Bu ◽  
Hongwei Liu
Keyword(s):  
Corrosion Resistance ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Coating Structure ◽  
Lower Porosity ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Different Thickness

In this paper, two kinds of micro-arc oxidation (MAO) coatings on TA2 with different thickness were prepared by controlled oxidation time and then were characterized for their composition, crystalline structure, and surface morphology. The effect of MAO treatment on electrochemical corrosion behaviors of TA2 in 3.5% NaCl solution were studied by the electrochemical measurements including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves. The results indicate that the electrochemical behavior of MAO coating is related to the coating structure. OCP can be used to evaluate the porosity of MAO coating. More positive OCP indicates coating with lower porosity and larger resistance obtained from EIS. The MAO treatment can significantly enhance the corrosion resistance of TA2, but the thickness increase of MAO coating could not further improve the corrosion resistance. In addition, because of the increase in effective surface area, the MAO treatment may enhance the cathode action of TA2 when the galvanic cell is composed of TA2 and other more negative metal, which in turn promotes the corrosion of negative metal.

Interaction between Sodium Molybdate and FSWed Wled of 5083 Effected by Time

2013 ◽  
Vol 699 ◽  
pp. 645-649
Author(s):  
Chang Bin Shen
Keyword(s):  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Sodium Molybdate ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Friction Stir ◽  
Base Materials ◽  
Corrosion Behaviors ◽  
5083 Aluminum Alloy

Similar welds composed of 5083 were produced by friction stir welding. In the solution of 0.2 M NaHSO3 and 0.6 M NaCl, with the addition of a given concentration sodium molybdate as the inhibitor, the electrochemical corrosion behaviors of the friction stir welds (FSW) and 5083 were comparatively investigated by potentiodynamic polarization curve tests and electrochemical impedance spectra (EIS) at the ambient temperature for different test periods. The results indicated that : with the extension of period, the inhibition efficiencies (IE) for both the weld and 5083 base materials enhanced, at the same period, the inhibition efficiency (IE) for the weld was beyond that for 5083 base materials, sodium molybdate may be thought of as an effective inhibitor for 5083 aluminum alloy, the interaction between inhibitor and weld is stronger than that between inhibitor and base materials.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

Application of Electrochemical Techniques to Characterization of the Corrosion Behaviors of GW63 Alloys

2007 ◽  
Vol 546-549 ◽  
pp. 571-574
Author(s):  
Xing Wu Guo ◽  
Jian Wei Chang ◽  
Shang Ming He ◽  
Peng Huai Fu ◽  
Wen Jiang Ding
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Cyclic Polarization ◽  
Time Curve ◽  
Completely Monotonic ◽  
Treatment Conditions ◽  
Impedance Variation ◽  
Corrosion Behaviors

The corrosion behavior of GW63 (Mg-6wt.%Gd-3wt.%Y-0.4wt.%Zr) alloys in 5% NaCl aqueous solution has been investigated by PARSTAT 2273 instrument. The Open Circuit Potential (ECORR) vs. time curve, cyclic polarization (Pitting Scans) curve and Electrochemical Impedance Spectroscopy (EIS) was measured for the GW63 alloys in as-cast and T6 heat treatment conditions. The EIS results indicated that the tendency of impedance variation for as-cast condition was monotonic decreasing, however, the tendency of variation for T6 condition was not completely monotonic but the total tendency was decreasing. The values of impedance of GW63 alloy at 0.1 Hz are about 103 ohm-cm2 for as-cast and T6 condition.

scholarly journals From Waste to Valuable Resource: Lignin as a Sustainable Anti-Corrosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Linear Sweep Voltammetry ◽  
Corrosion Current ◽  
Polymer Coatings ◽  
Open Circuit ◽  
Linear Sweep ◽  
Cyclic Potentiodynamic Polarization

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.

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