Anti-Corrosion Studies of Novel Conductive Polymer Coatings on Aluminum Alloys

1995 ◽  
Vol 413 ◽  
Author(s):  
R. J. Racicot ◽  
R. L. Clark ◽  
H-B Liu ◽  
S. C. Yang ◽  
M. N. Alias ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Corrosion Protection ◽  
Polymer Coating ◽  
Electrochemical Impedance ◽  
Conductive Polymer ◽  
Corrosion Current ◽  
Polymer Coatings ◽  
Anodized Aluminum ◽  
Cyclic Polarization ◽  
Order Of Magnitude

ABSTRACTWe report the corrosion protection properties of a novel conductive polymer coating on aluminum alloys. The conductive polymer coating is a double strand molecular complex of polyaniline and a polyelectrolyte. The double strand polyaniline offers advantages in stability and processability over other forms of conductive polymers. The coated aluminum alloys (AA7075- T6) were evaluated for corrosion protection in an aggressive salt environment of.5N NaCl solutions using cyclic polarization and electrochemical impedance spectroscopy. Corrosion current densities were calculated for uncoated alloy samples and alloys coated with the conductive and non-conductive derivative of the double strand polymer. The conductive form of the double strand polyaniline coating shows a two order of magnitude lowering of the corrosion current over the uncoated samples and a one order magnitude lowering over the non-conductive form of the polymer coated samples. The shape of the cyclic polarization data closely resembles results of sulfuric acid anodized aluminum. This data indicates that the conductive state of the polymer is required for improved corrosion protection and an anodized type protection is occurring.

Evidence of a Passive Layer Formation from a Conductive Polymer Coating on Aluminum Alloys

1996 ◽  
Vol 458 ◽  
Author(s):  
R. J. Racicot ◽  
S. C. Yang ◽  
R. Brown
Keyword(s):  
Aluminum Alloys ◽  
Polymer Coating ◽  
Electrochemical Impedance ◽  
Conductive Polymer ◽  
Interface Layer ◽  
Passive Layer ◽  
Experimental Results ◽  
Aluminum Surface ◽  
Acidic Salt ◽  
Rc Circuit

ABSTRACTEvidence for the formation of a passive layer between a conductive polymer coating and aluminum alloy surfaces is reported Experimental results from electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) on aluminum alloys coated with a novel double strand conductive polymer coating based on polyaniline reveal the evidence for the formation of passive layer. The key results are: (1) Modeling of EIS data is best fit with a three RC circuit, indicating a third interface between the polymer coating and the alloy's surface; (2) EIS testing in acidic salt solutions shows the conductive polymer coating performs differently and better than a typical anodized or chromáte conversion coating indicating a possibly different interface layer than a typical aluminum oxide and (3) SEM studies of the aluminum surface, after the polymer film is removed, indicates that this interfacial layer has a dense and smooth “oxide type” surface morphology. The experimental results are consistent with a mechanism in which the conducting polymer serves as a surface conversion agent that oxidizes the aluminum metal surface to form a passive layer.

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.

Characteristics of TiCN Film on AZ31 Magnesium Alloy Deposited by Radio Frequency Magnetron Sputtering

2012 ◽  
Vol 189 ◽  
pp. 124-129
Author(s):  
Jia Mu Huang ◽  
Xi Meng ◽  
Wei Chen ◽  
Shi Yu Sui
Keyword(s):  
Magnesium Alloy ◽  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Radio Frequency Magnetron ◽  
Az31 Magnesium Alloy ◽  
Titanium Carbonitride ◽  
Radio Frequency Magnetron Sputtering ◽  
Order Of Magnitude

Titanium carbonitride (TiCN) films were deposited on AZ31 magnesium alloy by radio frequency magnetron sputtering. The surface morphology and microstructure were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the corrosion resistance was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results show that TiCN coatings deposited on AZ31 magnesium alloy are amorphous, and reveal good adhesion onto the substrate. The corrosion current density of TiCN-coated magnesium alloy was 1.664×10-6 A/cm2, which decreased by more than one order of magnitude compared to the uncoated magnesium alloy (1.785×10-5 A/cm2).

scholarly journals Cation Effect in the Corrosion Inhibition Properties of Coumarate Ionic Liquids and Acrylic UV-Coatings

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2611
Author(s):  
Esther Udabe ◽  
Anthony Sommers ◽  
Maria Forsyth ◽  
David Mecerreyes
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Polymer Coating ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Polymer Coatings

Chromate free corrosion inhibitors are searched for to mitigate the economic loss caused by mid-steel corrosion. Here, we show metal-free organic inhibitors having free coumarate anions that can be used either as direct corrosion inhibitors or incorporated into a polymer coating obtained by UV-curing. Four different ionic liquid monomers and polymer coatings with hexoxycoumarate anion and different polymerizable counter cations were investigated. Potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analyses have verified their corrosion inhibition performance on a mild steel AS1020 surface. In the case of the coumarate ionic liquid monomers, the most promising inhibitor is the one coupled with the ammonium cation, showing an inhibition efficiency of 99.1% in solution followed by the imidazolium, pyridinium, and anilinium. Next, the ionic liquid monomers were covalently integrated into an acrylic polymer coating by UV-photopolymerization. In this case, the barrier effect of the polymer coating is combined with the corrosion inhibitor effect of the pendant coumarate anion. Here, the best polymer coatings are those containing 20% imidazolium and pyridinium cations, presenting a greater impedance in the EIS (Electrochemical Impedance Spectroscopy) measurements and less evidence of corrosion in the scribe tests. This article shows that the cationic moiety of coumarate based ionic liquids and poly(ionic liquid)s has a significant effect on their excellent corrosion inhibition properties for a mild steel surface exposed to aqueous chloride solutions.

Electrochemical Characteristics of Al-Based Coating on Magnesium Alloy Fabricated by Supersonic Particles Deposition

2013 ◽  
Vol 756-759 ◽  
pp. 85-88
Author(s):  
Xiao Ming Wang ◽  
Sheng Zhu ◽  
Qing Chang ◽  
Guo Feng Han
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Electrochemical Characteristics ◽  
Order Of Magnitude

Al-based coating on ZM5 magnesium alloy was prepared by Supersonic Particles Deposition (SPD). Electrochemical working station was utilized to test polarization curve, corrosion potential and electrochemical impedance spectroscopy etc. The results indicted that corrosion potential of Al-Si coating was about-767.6mV, much higher than that of ZM5 Mg-substrate; And corrosion current density of the coating sample decreased three order of magnitude than that of the uncoated. Compared to Mg-substrate, the radius of capacitive impedance arc of the coating enlarged and impedance modulus improved two order of magnitude.

Preparation and Corrosion Protection Effect of Electroactive Polyurethane Containing Amino-Capped Aniline Trimer

2010 ◽  
Vol 123-125 ◽  
pp. 1255-1258
Author(s):  
Chih Wei Peng ◽  
Jui Ming Yeh
Keyword(s):  
Corrosion Protection ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Passive Layer ◽  
Visible Absorption ◽  
Protection Effect ◽  
Reversible Redox ◽  
Cold Rolled ◽  
Uv Visible

Electroactive polyurethane (EPU) containing conjugated segments of electroactive amino-capped aniline trimer (ACAT) has been successfully synthesized and characterized through Fourier-Transformation infrared and UV–visible absorption spectroscopy. Subsequently, electroactivity (i.e., redox capability) of as-prepared EPU was investigated by electrochemical cyclic voltammetry (CV) studies. It was noticed that the as-prepared EPU exhibited reversible redox capability was found to reveal better corrosion protection effect on cold-rolled steel (CRS) electrodes than that of non-electroactive polyurethane based on a series of electrochemical measurements such as corrosion potential, polarization resistance, corrosion current and electrochemical impedance spectroscopy (EIS) studies in 5 wt-% NaCl electrolyte. This significant enhancement of corrosion protection on CRS electrodes as compared to non-electroactive polyurethane might be probably ascribed to the redox catalytic property of as-prepared EPU coatings inducing the formation of passive layer of metal oxide, as evidenced by the SEM and ESCA studies.

scholarly journals Influence of Milling Route on the Corrosion Passivation of Al-2%SiC Nanocomposites in Chloride Solutions

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1231
Author(s):  
Saud M. Almotairy ◽  
El-Sayed M. Sherif ◽  
Nabeel H. Alharthi ◽  
Hany S. Abdo ◽  
Hamad F. Alharbi ◽  
...  
Keyword(s):  
Ball Milling ◽  
Pitting Corrosion ◽  
Chloride Solution ◽  
Milling Time ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Cyclic Polarization ◽  
Elemental Analyses ◽  
Ball Milling Time ◽  
Corrosion Passivation

In this work, the fabrication of three Al-2wt.% SiC nanocomposites processed by novel milling route was carried out. The beneficial influence of milling route on the corrosion passivation of the new fabricated composites was investigated. The cyclic polarization measurements have proved that increasing the time of ball milling highly reduced the corrosion of Al-SiC nanocomposite via reducing obtained corrosion current and so increasing the corrosion resistance. These results were affirmed by the electrochemical impedance spectroscopy experiments. The pitting corrosion of the manufactured composites was also reported, and its intensity decreased with the increase of ball milling time. The electrochemical experiments were also performed after expanding the exposure time in the chloride solution to 24 and 48. It was found that both the uniform and pitting corrosion decrease with prolonging the time. The study was complemented by examining the surface morphology and the elemental analyses for the different composites by using surface analyses techniques.

scholarly journals Cr3C2-NiCr Coating for the Protection of API Steel Corrosion in Concentrated Sodium Chloride Solution

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 249
Author(s):  
El-Sayed M. Sherif ◽  
Magdy M. El Rayes ◽  
Hany S. Abdo
Keyword(s):  
Corrosion Resistance ◽  
Sodium Chloride ◽  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Protective Layer ◽  
Steel Corrosion ◽  
Corrosion Current ◽  
Cyclic Polarization ◽  
Current Time

In the present work, a layer of 75%Cr3C2−25%NiCr with thickness of 260 ± 15 µm was coated onto the API-2H pipeline steel surface using high-velocity oxy-fuel deposition. The effect of 75%Cr3C2−25%NiCr coating on the corrosion of the API steel after 1 h, 24 h, and 48 h exposure in 4.0% sodium chloride solutions is reported. The corrosion tests were performed using potentiodynamic cyclic polarization, electrochemical impedance spectroscopy, and chronoamperometric current–time techniques along with scanning electron microscopy and energy-dispersive X-ray analyses. The curves of polarization indicated that the presence of the coating increases the corrosion resistance of the steel through decreasing its corrosion current and corrosion rate. Impedance data showed that all resistances recorded higher values for the coated API steel. Chronoamperometric current–time measurements confirmed that the coated API steel has lower absolute current values and thus lower corrosion rate. All results proved that the presence of 75%Cr3C2−25%NiCr coating enhances the corrosion resistance of the API steel via the formation of a protective layer of Cr and Ni oxides, which could lead to decreasing the corrosion rate.

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