An Experimental and Finite Element Modeling Approach to Determining Degradation of Aircraft Coating Systems

2020 ◽  
Author(s):  
Steve Policastro ◽  
Erick Iezzi ◽  
Carlos Hangarter ◽  
Rachel Anderson ◽  
Attilio Arcari ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Environmental Parameters ◽  
Barrier Properties ◽  
Organic Coating ◽  
Coating System ◽  
Coating Properties ◽  
Surface Pretreatment ◽  
System Properties ◽  
Service Environments ◽  
Paint Removal

In order to delay the onset of corrosion structures subjected to atmospheric degradation, such as aircraft, exterior metal surfaces are frequently covered in a corrosion prevention organic coating system. Organic coating systems, in many cases, provide a reservoir of corrosion inhibitors along with establishing a critical electrolyte barrier between the atmosphere and the structure. These coating systems include a surface pretreatment, a primer barrier layer that can contain a sacrificial inhibitor additive, and a topcoat that also provides corrosion barrier properties and other additives for color. Improving our understanding, and modeling how these coating properties change, as a function of exposure to a variety of service environments can decrease maintenance costs associated with paint removal, and re-painting. A model that can incorporate the fundamental effects of various environmental parameters can provide damage predictions based upon the measured environmental data.To that end, the initial phase of this program has focused on testing and monitoring a US Navy aircraft coating system, exposed to a variety of degradation conditions that simulate the extreme ranges of environmental stresses expected to be seen in-service. Coating condition was monitored using electrochemical impedance spectroscopy (EIS) and characterized using equivalent-circuit models so that changes to the coating system properties could be quantified and tracked over time.

Corrosion resistance and characterization studies of calcium series chemical conversion film via green pretreatment on magnesium alloy

2016 ◽  
Vol 63 (6) ◽  
pp. 508-512
Author(s):  
Fengjing Wu ◽  
Xiaojuan Liu ◽  
Xin Xiao
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Chemical Conversion ◽  
Corrosion Current ◽  
Organic Coating ◽  
Hazardous Substances ◽  
Surface Pretreatment ◽  
Content Type ◽  
Az80 Magnesium Alloy

Purpose Magnesium alloys, although valuable, are reactive and require protection before its application in many fields. The purpose of this study was to evaluate a novel anticorrosive chemical conversion film on AZ80 magnesium alloy by environmental-friendly calcium series surface pretreatment. Design/methodology/approach The corrosion resistance of the film was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5 Wt.% NaCl solution. The surface morphologies, microstructure and composition of the film were investigated by scanning electron microscopy and energy-dispersive spectroscopy. Findings The corrosion current density of the calcium series film decreased by more than one order of magnitude as compared to that of the AZ80 magnesium alloy. The conversion film presented dry-mud morphology, and its thickness was estimated to be approximately 4 μm. The conversion film was highly hydrophilic, and the organic coating adhesion on treated AZ80 surface was approximately 13.5 MPa. Originality/value Excellent performance of the calcium-based chemical conversion film on Mg alloy was obtained, which does not contain heavy metals or fluorides and completely conforms to European RoHS (Restriction of Hazardous Substances) standard.

The Corrosion Behavior of Lacquered Tinplate in Functional Beverage

2011 ◽  
Vol 233-235 ◽  
pp. 1747-1751 ◽  
Author(s):  
Da Hai Xia ◽  
Ji Hui Wang ◽  
Shi Zhe Song ◽  
Bo Zhong ◽  
Zhe Wen Han
Keyword(s):  
Surface Morphology ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Organic Coating ◽  
Coating System ◽  
Substrate Metal ◽  
Bode Plot ◽  
Deterioration Process ◽  
Corrosion Pits

The deterioration process of the epoxy phenolic coated tinplate in functional beverage was studied by electrochemical impedance spectroscope (EIS). The surface morphology was characterized SPM and SEM. The results showed that corrosion pits were observed on the surface after exposing the coating system to functional beverage for 364 days. The breakages of the organic coating lead to the corrosion of substrate metal. A new parameterpextracting directly from the Bode plot was presented to characterize the deterioration degree of the coating system. Usingpvalue as the discrimination indicator of the deterioration degree of organic coating was presented in this paper.

EIS study of the corrosion behavior of an organic coating applied on Algerian oil tanker

2020 ◽  
Vol 117 (6) ◽  
pp. 610
Author(s):  
Nadia Hammouda ◽  
Kamel Belmokre
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Paint Film ◽  
Organic Coating ◽  
Diffusion Resistance ◽  
Double Layer Capacitance ◽  
Carbon Steel Surface ◽  
Chloride Environment ◽  
Oil Tanker ◽  
Epoxy Paint

Organic coatings are widely employed in the corrosion protection of most metal surfaces, particularly steel. They provide a barrier against corrosive species present in the environment, due to their high resistance to oxygen, water and ions transport. This study focuses on the evaluation of corrosion protection performance of epoxy paint on the carbon steel surface in chloride environment (3% NaCl) by Electrochemical Impedance Spectroscopy (EIS). The electrochemical behavior of painted surface was estimated by EIS parameters that contained paint film resistance, paint film capacitance and double layer capacitance. On the basis of calculation using EIS spectrums it was observed that pore resistance (Rpore) decreased with the appearance of doubled layer capacitance (Cdl) due to the electrolyte penetration through the film. This was further confirmed by the decrease of diffusion resistance (Rd) which was also the indicator of the deterioration of paint film protectiveness. Microscopic analyses have shown that oxidation dominates the corroded surfaces.

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.

Corrosion Inhibition of Mild Steel by Electrodeposited Poly(M-Aminophenol) Coating

2021 ◽  
Vol 317 ◽  
pp. 498-505
Author(s):  
Sabrina M. Yahaya ◽  
Mohamad Kamal Harun ◽  
Ismaliza Ismail ◽  
Rosmamuhamadani Ramli
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Impedance Measurement ◽  
Barrier Properties ◽  
Electrical Circuit ◽  
Significant Drop ◽  
Mild Steel Surface ◽  
Barrier Resistance ◽  
And Performance

In this study, poly(m-aminophenol) (PMAP) coating was electrochemically synthesized by cyclic voltammetry (CV) on mild steel surface to investigate the effects of its barrier protection within the scope of its electrochemical impedance towards further oxidation of the mild steel substrates. The developed PMAP coating were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The barrier resistance ability of PMAP coating towards corrosion of mild steel was determined in 0.5 M aqueous sodium chloride solution (NaCl) at various immersion times by the electrochemical impedance spectroscopy (EIS). The barrier properties were interpreted through impedance measurement using Nyquist and Bode plots. Equivalent electrical circuit models derived from the plots were employed to describe the coating barrier behaviour and performance. Data obtained showed that, the oxidation peak of PMAP coating were observed at potential +1.0 V (Ag/AgCl). The micrograph of FESEM indicates the formation of a dense and continous PMAP coatings. In FTIR analyses, the presence of peak around 1082 cm-1 ascribed to C–O–C etheric linkage which supported the formation of electro polymerized PMAP coating on mild steel surface. EIS measurement revealed that, PMAP coatings experienced a significant drop in total impedance values with time followed by the development of an electrochemical reactions on coating/metal interface, which indicates the gradual degradation of the barrier resistance ability of the PMAP coatings.

Electrochemical Impedance Spectroscopy Behaviour of NdFeB Coated Magnets in Saliva Solution for Orthodontic Applications

2015 ◽  
Vol 227 ◽  
pp. 515-518 ◽  
Author(s):  
Luigi Calabrese ◽  
Lucio Bonaccorsi ◽  
Chiara Borsellino ◽  
Angela Caprì ◽  
Francesca Fabiano ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Protective Action ◽  
Barrier Properties ◽  
Dip Coating ◽  
Coating Technique ◽  
Number Of Layers ◽  
Dip Coating Technique

In this work the assessment of the corrosion performances in saliva solution of NdFeB magnets coated with silane layers was studied for its application in orthodontic brackets. The silane film, deposited by dip coating technique, has been prepared with varying dipping steps, with the purpose to identify the number of layers able to achieve an optimal protective action. Corrosion protection performance, during immersion in Fusayama synthetic saliva solution, was evaluated by means electrochemical impedance spectroscopy (EIS). The silane coatings evidenced good barrier properties resulting in an improvement of the anti-corrosion performances of the magnets. Better results were observed for samples with at least 15 layers of silane, that evidenced still acceptable protective action after three days of immersion in a Fusayama synthetic saliva solution.

scholarly journals Preparation and Properties of Self-Healing and Self-Lubricating Epoxy Coatings with Polyurethane Microcapsules Containing Bifunctional Linseed Oil

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1578 ◽  
Author(s):  
Haijuan Yang ◽  
Qiufeng Mo ◽  
Weizhou Li ◽  
Fengmei Gu
Keyword(s):  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Linseed Oil ◽  
Salt Spray ◽  
Average Diameter ◽  
Organic Coating ◽  
Epoxy Coating ◽  
The Self ◽  
Self Healing ◽  
Pure Epoxy

An organic coating is commonly used to protect metal from corrosion, but it is prone to failure due to microcracks generated by internal stress and external mechanical action. The self-healing and self-lubricating achieved in the coating is novel, which allows an extension of life by providing resistance to damage and repair after damage. In this study, a new approach to microencapsulating bifunctional linseed oil with polyurethane shell by interfacial polymerization. Moreover, the self-healing and self-lubricating coatings with different concentrations of microcapsules were developed. The well-dispersed microcapsules showed a regular spherical morphology with an average diameter of ~64.9 μm and a core content of 74.0 wt.%. The results of the salt spray test demonstrated that coatings containing microcapsules still possess anticorrosion, which is improved with the increase of microcapsules content, after being scratched. The results of electrochemical impedance spectroscopy showed a |Z|f=0.01Hz value of 104 Ω·cm2 for pure epoxy coating after being immersed for 3 days, whereas the coating with 20 wt.% microcapsules was the highest, 1010 Ω·cm2. The results of friction wear showed that the tribological performance of the coating was enhanced greatly as microcapsule concentration reached 10 wt.% or more, which showed a 86.8% or more reduction in the friction coefficient compared to the pure epoxy coating. These results indicated that the coatings containing microcapsules exhibited excellent self-healing and self-lubricating properties, which are positively correlated with microcapsules content.

scholarly journals Corrosion Protection of A36 Steel with SnO2 Nanoparticles Integrated into SiO2 Coatings

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 385 ◽  
Author(s):  
Ana Karen Acero-Gutiérrez ◽  
Ana Lilia Pérez-Flores ◽  
Jesús Gilberto Godínez-Salcedo ◽  
Joel Moreno-Palmerin ◽  
Ángel de Jesús Morales-Ramírez
Keyword(s):  
Corrosion Protection ◽  
Corrosion Inhibition ◽  
Silicon Oxide ◽  
Electrochemical Impedance ◽  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Barrier Properties ◽  
Dip Coating ◽  
Uncoated Sample ◽  
A36 Steel

Tin oxide (SnO2) nanoparticles were successfully added to silicon oxide (SiO2) coatings deposited on A36 steel by the sol-gel and dip-coating methods. These coatings were developed to improve the performance of corrosion protection of steel in a 3 wt % NaCl solution. The effects of modifying the SnO2 particle concentration from 0–7.5 vol % were investigated by polarization resistance, Tafel linear polarization, and electrochemical impedance spectroscopy (EIS). The formation of protective barriers and their corrosion inhibition abilities were demonstrated. It was found by electrochemical studies that all of the coated samples presented higher corrosion resistances compared with an uncoated sample, indicating a generally beneficial effect from the incorporation of the nanoparticles. Furthermore, it was established that the relationship between the SnO2 content and the corrosion inhibition had parabolic behaviour, with an optimum SnO2 concentration of 2.5 vol %. EIS showed that the modified coatings improved barrier properties. The resistance for all of the samples was increased compared with the bare steel. The corrosion rate measurements highlighted the corrosion inhibition effect of SnO2 nanoparticles, and the Tafel polarization curves demonstrated a decrease in system dissolution reactions at the optimal nanoparticle concentration.

scholarly journals Electrochemical Impedance Spectroscopy Evaluation of Organic Coating on Mild Steel

2018 ◽  
Vol 7 (3.11) ◽  
pp. 30
Author(s):  
Zailelah Zainoldin ◽  
Hadariah Bahron ◽  
Mohamad Kamal Harun ◽  
Syaidah Athirah Dzolin
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Organic Coating ◽  
Electrical Equivalent Circuit ◽  
Mild Steel Surface ◽  
Electro Oxidation ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Voltammetric Technique

Electro-oxidation of 4-hydroxybenzalaniline in alkaline solution on mild steel surface was successfully carried out using cyclic voltammetric technique. Results demonstrated that brownish colour appeared on the mild steel surface after the cycle of voltammetric study. The presence of film was confirmed by the EIS measurement whereas the Nyquist plots obtained from EIS measurements were fitted with suitable electrical equivalent circuit. The coated mild steel exhibit better polarization resistance than uncoated mild steel.  

scholarly journals Graphene Oxide/Polyaniline Nanocomposites Used in Anticorrosive Coatings for Environmental Protection

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1215
Author(s):  
Shuanqiang Yang ◽  
Shu Zhu ◽  
Ruoyu Hong
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Barrier Properties ◽  
Living Environment ◽  
Metal Corrosion ◽  
Corrosion Performance ◽  
Corrosion Properties ◽  
Anticorrosive Coatings ◽  
Vis Spectroscopy

In recent years, metal corrosion causes serious threats to the economy of the world and the living environment. Hence, it is very important to seek non-toxic and environmentally friendly materials with metal anti-corrosion properties for the sustainable development of society. The barrier properties of graphene oxide (GO) and the special electrochemical property of polyaniline (PANI) can significantly improve the corrosion resistance of metals. Herein, we developed an in-situ polymerization method to prepare graphene oxide/polyaniline (GO/PANI) nanocomposites with unique anti-corrosion properties. The obtained GO/PANI nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermalgravimetric analysis, UV–vis spectroscopy and scanning electron microscopy. The as-prepared composite materials were uniformly dispersed in epoxy resin to prepare anticorrosive coatings and coated on the surface of steel. The anti-corrosion performance of the coatings was measured by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique. The EIS results showed that the total impedance of epoxy/GO/PANI coatings is greater than epoxy/PANII coatings, and the impedance module value can reach 8.67 × 108 Ω·cm2. In general, it is concluded that the anti-corrosion performance of GO/PANI coating is significantly higher than PANI coating and pure GO coating.

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