scholarly journals Comparative Study of Corrosion Properties of Different Graphene Nanoplate/Epoxy Composite Coatings for Enhanced Surface Barrier Protection

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 285 ◽  
Author(s):  
Randy Raymond Abakah ◽  
Feng Huang ◽  
Qian Hu ◽  
Yicong Wang ◽  
Liu Jing
Keyword(s):  
Electrochemical Impedance ◽  
Epoxy Composite ◽  
Composite Coatings ◽  
Salt Spray ◽  
Polymeric Materials ◽  
Passive Layer ◽  
Surface Barrier ◽  
Corrosion Properties ◽  
Graphene Nanoparticles ◽  
Enhanced Surface

Loading of graphene to polymeric materials has proven a widespread increase in the corrosion properties of nanocomposites. In this study, graphene nanoplatelets (Gnps)/epoxy composite coatings were prepared by incorporating three commercial graphene nanoparticles (C750, M15, and X50 Gnps) into epoxy resin. The morphological impact of the Gnps on the surface barrier protection were evaluated in terms of coating’s adhesion to the substate, hydrophobicity and water uptake performance. Salt spray resistance and Electrochemical Impedance Spectroscopy (EIS) authenticated that the coating integrated with C750 Gnp remarkably improved the anti-corrosion performance of neat epoxy composite coatings. A robust passive layer and surface barrier characteristics formed by the composite coatings incorporated with C750 nanoparticle should be the main reason for better protection properties offered by C750 Gnp/epoxy nanocomposites. At the same time, homogeneous dispersion and lesser agglomerates in C750 Gnp/epoxy composite coatings mainly contributed to the coating’s excessive corrosion resistance.

Corrosion Resistance of Nickel-Based Composite Coatings Reinforced by Spherical Tungsten Carbide

2020 ◽  
Vol 993 ◽  
pp. 1075-1085
Author(s):  
Li Fan ◽  
Hai Yan Chen ◽  
Hai Liang Du ◽  
Yue Hou ◽  
Qian Cheng
Keyword(s):  
Corrosion Resistance ◽  
Tungsten Carbide ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Salt Spray ◽  
Electrochemical Corrosion ◽  
Corrosion Properties ◽  
Oil Drilling ◽  
Passivation Film ◽  
Spherical Tungsten Carbide

Nickel-based composite coatings reinforced by spherical tungsten carbide were deposited on 42CrMo alloy steel using plasma transfer arc welding (PTAW) process. Their electrochemical corrosion properties in NaCl solution under atmospheric and high pressure were studied by polarization curve, electrochemical impedance spectroscopy. The corrosion and erosion resistance of the coatings were also investigated by salt spray corrosion and erosion corrosion tests. The results show that the self-corrosion potential of the composite coatings increased with the increase of tungsten carbide content, and the Cr element in Ni60 sample formed a stable and compact passivation film. Compared with corrosion at atmospheric pressure, the adsorption and penetration of Cl- on the coating surface enhanced due to the increase of Cl- activity under pressure, thereby to weaken the corrosion resistance. The Samples that passivated in salt spray environment, cannot completely hinder the corrosion of the coating, just only to slow down the corrosion. This study can provide theoretical basis for deep-sea oil drilling and production engineering equipment.

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

scholarly journals Using Graphene-Based Composite Materials to Boost Anti-Corrosion and Infrared-Stealth Performance of Epoxy Coatings

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1603
Author(s):  
Meng-Jey Youh ◽  
Yu-Ren Huang ◽  
Cheng-Hsiung Peng ◽  
Ming-Hsien Lin ◽  
Ting-Yu Chen ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Graphene Nanosheets ◽  
Salt Spray ◽  
Corrosion Current ◽  
Filler Concentration ◽  
Epoxy Coatings ◽  
Corrosion Properties ◽  
Water Contact ◽  
Different Temperatures ◽  
Thermal Signature

Corrosion prevention and infrared (IR) stealth are conflicting goals. While graphene nanosheets (GN) provide an excellent physical barrier against corrosive agent diffusion, thus lowering the permeability of anti-corrosion coatings, they have the side-effect of decreasing IR stealth. In this work, the anti-corrosion properties of 100-μm-thick composite epoxy coatings with various concentrations (0.01–1 wt.%) of GN fillers thermally reduced at different temperatures (300 °C, 700 °C, 1100 °C) are first compared. The performance was characterized by potentiodynamic polarization scanning, electrochemical impedance spectroscopy, water contact angle and salt spray tests. The corrosion resistance for coatings was found to be optimum at a very low filler concentration (0.05 wt.%). The corrosion current density was 4.57 × 10−11 A/cm2 for GN reduced at 1100 °C, showing no degradation after 500 h of salt-spray testing: a significant improvement over the anti-corrosion behavior of epoxy coatings. Further, to suppress the high IR thermal signature of GN and epoxy, Al was added to the optimized composite at different concentrations. The increased IR emissivity due to GN was not only eliminated but was in fact reduced relative to the pure epoxy. These optimized coatings of Al-GN-epoxy not only exhibited greatly reduced IR emissivity but also showed no sign of corrosion after 500 h of salt spray test.

Performance of Thermal Insulation Reflective Composite Coatings

2011 ◽  
Vol 239-242 ◽  
pp. 1771-1774 ◽  
Author(s):  
Meng Qiu Jia ◽  
Yu Hong Jin
Keyword(s):  
Aqueous Solution ◽  
Thermal Insulation ◽  
Heat Insulation ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Insulation Property ◽  
Corrosion Properties ◽  
Rutile Titanium Dioxide ◽  
Insulation Performance ◽  
Good Heat

Reflective topcoat and thermal insulation mid-coat composite coatings system was used in this work. The effect of the content of the hollow glass micro-beads and rutile titanium dioxide on the heat insulation performance and the reflectivity of the coatings were investigated, respectively. The heat insulation performance and the reflectivity of the thermal insulation reflective composite coatings (TIRCCs) were characterized by self-prepared experimental device. The results showed the good heat insulation property, and the insulated temperature reached 12-15°C, and the reflectivity was up to 95%. The anti-corrosion and anti-penetration of the TIRCCs were studied by electrochemical impedance spectroscopy (EIS) technique. The results showed that the resistance of the TIRCCs still be maintained at 108Ω·cm2 after 30 days in the 3.5% aqueous solution of sodium chloride. So The TIRCCs can be used on the surface of the steal structure for decreasing the temperature and enhancing anti-corrosion properties.

Study of Microstructure and Corrosion Resistance of Zinc Electrodeposits before and after Black Chromating

2017 ◽  
Vol 751 ◽  
pp. 119-124
Author(s):  
Kanokwan Saengkiettiyut ◽  
Pranee Rattanawaleedirojn ◽  
Adisak Thueploy ◽  
Jumpot Wanichsampan ◽  
Yuttanant Boonyongmaneerat
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Alkaline Electrolyte ◽  
Corrosion Properties ◽  
Electrochemical Testing ◽  
Before And After ◽  
Coat Layer ◽  
Zinc Coatings ◽  
Salt Spray Testing

In this work, microstructure and corrosion properties of zinc electroplated steel before and after black chromating was investigated. The test samples were prepared by electrodeposition process, using a commercially-available alkaline electrolyte. Subsequently, the galvanized samples were applied with a black chromate-based passivation layer and a clear top-coat layer. Their microstructures were examined using X-ray diffractometry and scanning electron microscopy. The corrosion resistance of the samples was assessed with the salt spray test, following the ASTM B117, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization in 5 wt.% NaCl solutions. The study showed that zinc electroplated steels exhibit (110) crystallographic orientation. The passivation and top-coat layers did not affect the microstructure of the zinc layer, and covered uniformly on the zinc layer for all sets of samples. The corrosion resistant results obtained from salt spray testing and electrochemical testing revealed that the microstructure of zinc coatings prepared by using different applied current did not influence on their corrosion resistance markedly. While black passivation followed by top coating provided a significant improvement on corrosion resistance of the coatings.

Effect of metal ions on the anti-corrosion properties of γ-glycidoxypropyltrimethoxysilane coatings on cold-rolled iron

2016 ◽  
Vol 63 (2) ◽  
pp. 82-88 ◽  
Author(s):  
Shengsong Ge ◽  
Menglong Li ◽  
Qian Shao ◽  
Ke Liu ◽  
Junxiang Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Coating Process ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Content Type ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Cold Rolled

Purpose – This paper aims to clarify the effect of metal ions added in the γ-glycidoxypropyltrimethoxysilane (γ-GPS) solutions on the anti-corrosion properties of the γ-GPS coatings on cold-rolled iron (CRI). Design/methodology/approach – The transformations of functional groups involved in reactions during the coating process were characterized by Fourier transformed infrared spectroscopy (FTIR), and the thickness of the γ-GPS coatings on the CRI substrates was measured using high-powered microscopy. The anti-corrosion properties of γ-GPS-treated samples were evaluated by neutral salt spray tests, polarization curves and electrochemical impedance spectroscopy measurements. Findings – The results show that Zn2+ and Mg2+ in the γ-GPS solutions promote the formation of Si-O-Si and Si-O-Fe bonds and improve the anti-corrosion properties of the γ-GPS coatings on CRI. However, Al3+ and Na+ in the γ-GPS solutions do not play this role. Originality/value – Although there have been previous research studies on the γ-GPS coatings on CRI, this paper is the first to study the effect of metal ions added in the silane solutions on the anti-corrosion properties of the γ-GPS coatings, and it has been confirmed that the anti-corrosion properties changed when Zn2+ (or Mg2+) is present.

scholarly journals Improvement of AZ91 Alloy Corrosion Properties by Duplex NI-P Coating Deposition

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1357 ◽  
Author(s):  
Jaromír Wasserbauer ◽  
Martin Buchtík ◽  
Jakub Tkacz ◽  
Stanislava Fintová ◽  
Jozef Minda ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Az91 Alloy ◽  
Neutral Salt ◽  
Az91 Magnesium Alloy ◽  
Corrosion Properties ◽  
Az91 Magnesium

The corrosion behavior of duplex Ni-P coatings deposited on AZ91 magnesium alloy was studied. The electroless deposition process of duplex Ni-P coating consisted in the preparation of low-phosphorus Ni-P coating (5.7 wt.% of P), which served as a bond coating and high-phosphorus Ni-P coating (11.5 wt.% of P) deposited on it. The duplex Ni-P coatings with the thickness of 25, 50, 75 and 100 µm were deposited on AZ91 magnesium alloy. The electrochemical corrosion behavior of coated AZ91 magnesium alloy was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization method in 0.1 M NaCl. Obtained results showed a significant improvement in the corrosion resistance of coated specimens when compared to uncoated AZ91 magnesium alloy. From the results of the immersion tests in 3.5 wt.% NaCl, 10% solution of HCl and NaOH and 5% neutral salt spray, a noticeable increase in the corrosion resistance with the increasing thickness of the Ni-P coating was observed.

Diffusion Analysis of Chloride in Concrete Following Electrokinetic Nanoparticle Treatment

2010 ◽  
Author(s):  
K. Kupwade-Patil ◽  
T. J. John ◽  
B. Mathew ◽  
H. Cardenas ◽  
H. Hegab
Keyword(s):  
Diffusion Coefficient ◽  
Reinforced Concrete ◽  
Diffusion Coefficients ◽  
Sea Water ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Chloride Concentration ◽  
Passive Layer ◽  
Chloride Diffusion ◽  
Equivalent Circuit Analysis

Concrete is a highly porous material which is susceptible to the migration of highly deleterious species such as chlorides and sulfates. Various external sources including sea salt spray, direct sea water wetting, deicing salts and brine tanks harbor chlorides that can enter reinforced concrete. Chlorides diffuse into the capillary pores of concrete and come into contact with the rebar. When chloride concentration at the rebar exceeds a threshold level it breaks down the passive layer of oxide, leading to chloride induced corrosion. Application of electrokinetics using positively charged nanoparticles for corrosion protection in reinforced concrete structures is an emerging technology. This technique involves the principle of electrophoretic migration of nanoparticles to hinder chloride diffusion in the concrete. The re-entry of the chlorides is inhibited by the electrodeposited assembly of the nanoparticles at the rebar interface. In this work electrochemical impedance spectroscopy (EIS) combined with equivalent circuit analysis was used to predict chloride diffusion coefficients as influenced by nanoparticle treatments. Untreated controls exhibited a diffusion coefficient of 3.59 × 10−12 m2/s which is slightly higher than the corrosion initiation benchmark value of 1.63 × 10−12 m2/s that is noted in the literature for mature concrete with a 0.5 water/cement mass ratio. The electrokinetic nanoparticle (EN) treated specimens exhibited a diffusion coefficient of 1.41 × 10−13m2/s which was 25 times lower than the untreated controls. Following an exposure period of three years the mature EN treated specimens exhibited lower chloride content by a factor of 27. These findings indicate that the EN treatment can significantly lower diffusion coefficients thereby delaying the initiation of corrosion.

Paintability of Traditional and Chromium(VI)-Free Conversion Layers on Galvanized Steels

2008 ◽  
Vol 589 ◽  
pp. 415-420
Author(s):  
Szilvia Kőszegi ◽  
Éva Dénes
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Earth Metal ◽  
Organic Coating ◽  
Galvanized Steel ◽  
Cerium Chloride ◽  
Corrosion Properties ◽  
Chromium Vi ◽  
Pre Treatment ◽  
Duplex Systems

Continuous hot dip galvanized steel samples have been treated with traditional chromium(VI)-containing passivator and environment friendly rare-earth metal containing ceriumsalt and lanthanum-salt based solutions using different immersion times. The treated surfaces have been examined by scanning electron microscope equipped with an energy dispersive X-ray analyser. After the pre-treatment the samples have been spray-painted with epoxy-based organic paint. The adhesion was tested with bending and cross-cut test. Thereafter salt spray test was performed on duplex systems. After 48 hours samples have been taken out from the corrosion chamber in order to perform electrochemical impedance measurements for 24 hours. Based on the results the most promising passivation among the chromium(VI)-free solutions has been found to be the cerium-salt based treatment. The adhesion of the organic coating was better on cerium-chloride treated substrate than on chromated one, while the anti corrosion properties of the two duplex systems were comparable.

scholarly journals Characterization of the passive films on electrodeposited Fe-Ni-Cr alloys in borate solution at pH 8.4

2007 ◽  
Vol 5 (4) ◽  
pp. 931-950 ◽  
Author(s):  
Laura Sziráki ◽  
Ernő Kuzmann ◽  
Colin Chisholm ◽  
Mahmoud El-Sharif ◽  
Lilla Bóbics ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Passive Layer ◽  
Passive Films ◽  
Corrosion Properties ◽  
Nickel Chromium ◽  
Iron Nickel ◽  
The Stability ◽  
Dissolution Corrosion ◽  
Borate Solution

AbstractThe corrosion properties of the passive layers formed on iron-nickel-chromium electrodeposits of Fe29Ni51Cr20 were investigated in 0.3 M borate solution at a‘ pH of 8.4. On the basis of measurements by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy, a low passive dissolution/corrosion rate was identified for the electrodeposited Fe-Ni-Cr alloys due to the nature of the established corrosion layer. The stability of this passive layer was further enhanced after corrosion under oxidizing conditions. Mössbauer spectroscopic measurements confirmed the existence of a thin passive layer on the amorphous electrodeposits.

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