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16 pages, 3934 KiB

Open AccessArticle

Corrosion Resistance and Biological Properties of Pure Magnesium Modified by PEO in Alkaline Phosphate Solutions

by Mónica Echeverry-Rendón, Luisa F. Berrio, Sara M. Robledo, Jorge A. Calderón, Juan G. Castaño and Felix Echeverría

Corros. Mater. Degrad. 2023, 4(2), 196-211; https://doi.org/10.3390/cmd4020012 - 23 Mar 2023

Cited by 2 | Viewed by 1960

Abstract

Magnesium (Mg) has been explored during the last few decades in the biomedical industry as a biodegradable implant. However, mechanical properties and corrosion resistance are still big concerns for clinical use. Therefore, this study proposes a suitable surface modification of the Mg by [...] Read more.

Magnesium (Mg) has been explored during the last few decades in the biomedical industry as a biodegradable implant. However, mechanical properties and corrosion resistance are still big concerns for clinical use. Therefore, this study proposes a suitable surface modification of the Mg by plasma electrolytic oxidation (PEO) to improve its corrosion resistance and biological performance. Mg samples were processed in a galvanostatic mode using an electrolytic solution of a phosphate compound supplemented with either potassium pyrophosphate or sodium-potassium tartrate. The obtained coatings were physiochemically characterized by SEM, XRD, EDS, and micro-Raman spectroscopy. The corrosion resistance of the coatings was studied using a hydrogen evolution setup and electrochemical tests. Finally, the biological performance of the material was evaluated by using an indirect test with osteoblasts. Obtained coatings showed a porous morphology with thicknesses ranging from 2 to 3 µm, which was closely dependent on the PEO solution. The corrosion resistance tests improved the degradation rate compared to the raw material. Additionally, an unreported active–passive corrosion behavior was evidence of a protective layer of corrosion products underneath the anodic coating. Indirect in vitro cytotoxicity assays indicated that the coatings improved the biocompatibility of the material. In conclusion, it was found that the produced coatings from this study not only lead to material protection but also improve the biological performance of the material and ensure cell survival, indicating that this could be a potential material used for bone implants. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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16 pages, 5784 KiB

Open AccessArticle

Hybrid Polyurethane/Polypyrrole Composite Coatings on Passivated 316L SS for Surface Protective Action against Corrosion in Saline Medium

by Arumugam Madhan Kumar, Akeem Yusuf Adesina, Jothi Veeramani, Mohammad Mizanur Rahman and J. S. Nirmal Ram

Corros. Mater. Degrad. 2022, 3(4), 612-627; https://doi.org/10.3390/cmd3040033 - 31 Oct 2022

Cited by 5 | Viewed by 1592

Abstract

Hybrid treatments consisting of surface modification and subsequent protective coatings have gained extensive attention among corrosion mitigation approaches for a wide variety of structural metallic materials. This study aims to review the enhancement of the corrosion protection performance of polyurethane (PU) coatings on [...] Read more.

Hybrid treatments consisting of surface modification and subsequent protective coatings have gained extensive attention among corrosion mitigation approaches for a wide variety of structural metallic materials. This study aims to review the enhancement of the corrosion protection performance of polyurethane (PU) coatings on 316L stainless steel (SS) specimens. This was achieved via a two-step strategic treatment, primarily by electrochemical passivation and subsequent deposition of PU composite coatings with the different feed ratio of synthesized polypyrrole (PPy) nanoparticles. The effect of different applied voltage on the surface features and the corrosion behavior of the passivated SS surfaces was systematically investigated using surface characterization techniques and a potentiodynamic polarization test in a NaCl solution. Surface morphological images revealed the porous structure on the passivated surface. It is inferred from the topographical surface results that homogeneous surface roughness was achieved with the applied voltage of 5 V. Infra-red spectroscopic results validate the formation of PU/PPy composite coatings and the intermolecular chemical interaction between the PU and PPy moieties. Furthermore, corrosion measurements corroborate the improved corrosion resistance of PU/30PPy coatings with higher values of charge transfer resistance, R_ct (1.0869 × 10⁷ Ω cm²), and film resistance, Rf (2.258 × 10⁵ Ω cm²), with the lowest values of corrosion, i_corr (4.7 × 10⁻³ µA cm⁻²) compared to that of the PU/Bare specimen. In conclusion, it is confirmed that the passivated surface enhances the corrosion resistance performance of PU coated SS, and this performance is further increased with the incorporation of PPy particles. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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17 pages, 44312 KiB

Open AccessArticle

N-b-Hydroxyethyl Oleyl Imidazole as Synergist to Enhance the Corrosion Protection Effect of Natural Cocoyl Sarcosine on Steel

by Saad E. Kaskah, Gitta Ehrenhaft, Jörg Gollnick and Christian B. Fischer

Corros. Mater. Degrad. 2022, 3(3), 536-552; https://doi.org/10.3390/cmd3030029 - 08 Sep 2022

Cited by 2 | Viewed by 1612

Abstract

To investigate the corrosion protection behavior of naturally derived cocoyl sarcosine in combination with N-b-hydroxyethyl oleyl imidazole for steel CR4 in 0.1 M NaCl, different evaluation systems (weight loss, electrochemical measurements, and spray corrosion tests) were used. Both compounds were tested [...] Read more.

To investigate the corrosion protection behavior of naturally derived cocoyl sarcosine in combination with N-b-hydroxyethyl oleyl imidazole for steel CR4 in 0.1 M NaCl, different evaluation systems (weight loss, electrochemical measurements, and spray corrosion tests) were used. Both compounds were tested in different concentrations (25–100 mmol/L) and with variable dip coating times (1–30 min), first individually and then in combination, to check any synergistic effects for surface protection. Both showed only an insignificant corrosion inhibiting effect with less than 50% efficiency at all concentrations and dip coating times if used alone. In contrast, compound combinations revealed an improved corrosion inhibition correlated with higher concentrations. Across all methods, the compound combination concentration of 100 mmol/L resulted in improved efficiency of up to 83% for gravimetric tests, up to 84% for the impedance measure and more than 91% for potentiodynamic polarization. Dip coating variations proved 10 min to be the best option for all compounds with a maximum efficiency of up to 86% for the compound combination. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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17 pages, 8666 KiB

Open AccessArticle

Corrosion Behavior of Stainless Steels in CO₂ Absorption Process Using Aqueous Solution of Monoethanolamine (MEA)

by Fani Stergioudi, Aikaterini Baxevani, Christina Florou, Nikolaos Michailidis, Evie Nessi, Athanasios I. Papadopoulos and Panagiotis Seferlis

Corros. Mater. Degrad. 2022, 3(3), 422-438; https://doi.org/10.3390/cmd3030025 - 04 Aug 2022

Cited by 4 | Viewed by 3591

Abstract

The corrosion behavior of two stainless steels (316L and 304L) was evaluated using a CO₂-loaded aqueous solution of 30 wt.% monoethanolamine (MEA) with a view to simulating corrosion related mechanisms in amine treatment procedures. Corrosion behavior was experimentally evaluated as a [...] Read more.

The corrosion behavior of two stainless steels (316L and 304L) was evaluated using a CO₂-loaded aqueous solution of 30 wt.% monoethanolamine (MEA) with a view to simulating corrosion related mechanisms in amine treatment procedures. Corrosion behavior was experimentally evaluated as a function of CO₂ loading and solution temperature, using electrochemical techniques (polarization curves, cyclic polarization, and EIS measurement). The results reveal that the aqueous MEA solution containing CO₂ creates a favorable environment for the corrosion of both stainless steels. The rate of corrosion is accelerated when the temperature of the loaded MEA solution rises, which was attributed to the thermal degradation of the loaded MEA, thus causing higher kinetics of the cathodic reactions at higher temperatures. More specifically, for the SS 304L the corrosion rate is almost doubled when the solution temperature is increased from 25 °C to 40 °C and is quadrupled when the solution temperature rises to 80 °C. For the SS 316L, the corrosion rate becomes almost threefold and sixfold upon increasing temperature of the load amine solution to 40 °C and 80 °C, respectively. The overall corrosion rate of SS 316L is lower with respect to the SS 304L for the same temperature and loading conditions. The essential dependency of corrosion rate on solution type (unloaded and loaded MEA solution) demonstrates that the corrosion process and reactions are controlled by a diffusion mechanism. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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17 pages, 4543 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Green-High-Performance PMMA–Silica–Li Barrier Coatings

by Andressa Trentin, Victória Hellen Chagas, Mayara Carla Uvida, Sandra Helena Pulcinelli, Celso Valentim Santilli and Peter Hammer

Corros. Mater. Degrad. 2022, 3(3), 303-319; https://doi.org/10.3390/cmd3030018 - 24 Jun 2022

Cited by 2 | Viewed by 2031

Abstract

Organic-inorganic coatings based on polymethyl methacrylate (PMMA)–silica–lithium are an efficient alternative to protect metals against corrosion. Although the preparation methodology is established and the thin coatings (~10 µm) are highly protective, the use of an environmentally friendly solvent has not yet been addressed. [...] Read more.

Organic-inorganic coatings based on polymethyl methacrylate (PMMA)–silica–lithium are an efficient alternative to protect metals against corrosion. Although the preparation methodology is established and the thin coatings (~10 µm) are highly protective, the use of an environmentally friendly solvent has not yet been addressed. In this work, PMMA–silica coatings were synthesized using 2-propanol as a solvent and deposited on aluminum alloy AA7075, widely used in the aeronautical industry. Different concentrations of lithium carbonate (0–4000 ppm) were incorporated into the hybrid matrix to study the structural and inhibitive effects of Li⁺ in terms of barrier efficiency of the coatings in contact with saline solution (3.5% NaCl). Structural and morphological characterization by low-angle X-ray scattering, X-ray photoelectron spectroscopy, atomic force microscopy, thermogravimetric analysis, thickness, and adhesion measurements, showed for intermediate lithium content (500–2000 ppm) the formation of a highly polymerized PMMA phase covalently cross-linked by silica nodes, which provide strong adhesion to the aluminum substrate (15 MPa). Electrochemical impedance spectroscopy (EIS) results revealed an excellent barrier property in the GΩ cm² range and durability of more than two years in a 3.5% NaCl solution. This performance can be attributed to the formation of a highly reticulated phase in the presence of Li, which hinders the permeation of water and ions. Additionally, the self-healing ability of scratched samples was evidenced by EIS assays showing a fast Li-induced formation of insoluble products in damaged areas; thus, constituting an excellent eco-friendly solution for corrosion protection of aerospace components. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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19 pages, 8664 KiB

Open AccessArticle

Fabrication of Cobalt-Based Nano-Composite Film for Corrosion Mitigation of Copper in Flow Chloride Medium

by Vitalis I. Chukwuike and Rakesh C. Barik

Corros. Mater. Degrad. 2021, 2(4), 743-761; https://doi.org/10.3390/cmd2040040 - 08 Dec 2021

Cited by 4 | Viewed by 2625

Abstract

Corrosion of metals leads to high maintenance costs, as well as potential threats to structural health and safety. Here, we demonstrate the coating of cobalt tungstate (CoWO₄) nanoparticles (NPS)/5-mercapto-1-phenyl-1 H-tetrazole derivative (MPT) used as a nano-composite film on Cu surface for [...] Read more.

Corrosion of metals leads to high maintenance costs, as well as potential threats to structural health and safety. Here, we demonstrate the coating of cobalt tungstate (CoWO₄) nanoparticles (NPS)/5-mercapto-1-phenyl-1 H-tetrazole derivative (MPT) used as a nano-composite film on Cu surface for the blocking of micropores to hinder the propagation of metastable pits in an aggressive NaCl medium. The mechanism of interaction between the nanoparticles and tetrazole derivative, in addition to the mode of anchoring to the metal surface and blocking the penetration of chloride ions (

{Cl}^{-}

), are all investigated. In this investigation, CoWO₄ is synthesized via a wet chemical route and thereafter, is combined with MPT at an optimized ratio thus formulating a nano-composite corrosion inhibitor which in solution gets coated on Cu surface. Atomic force and scanning electron microscopic images of the bare Cu reveal dip pits, which by the coating of the nano-composite are suppressed at the nucleation stage during exposure to the aggressive 3.5% NaCl electrolyte under flow conditions. Electrochemical analysis shows high protection of Cu up to 97% efficiency in the presence of the newly formulated nano-composite inhibitor film. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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Review

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33 pages, 6580 KiB

Open AccessReview

Polymer-Based Coating for Steel Protection, Highlighting Metal–Organic Framework as Functional Actives: A Review

by Sarah Bill Ulaeto, Rajimol Puthenpurackal Ravi, Inime Ime Udoh, Gincy Marina Mathew and Thazhavilai Ponnu Devaraj Rajan

Corros. Mater. Degrad. 2023, 4(2), 284-316; https://doi.org/10.3390/cmd4020015 - 29 Apr 2023

Cited by 8 | Viewed by 6038

Abstract

Polymer-based coatings are a long-established category of protective coatings for metals and alloys regarding corrosion inhibition. The polymer films can degrade, and when coated on metallic substrates, the degradation facilitates moisture and oxygen penetration, reducing the polymer film’s adhesion to the metallic substrate [...] Read more.

Polymer-based coatings are a long-established category of protective coatings for metals and alloys regarding corrosion inhibition. The polymer films can degrade, and when coated on metallic substrates, the degradation facilitates moisture and oxygen penetration, reducing the polymer film’s adhesion to the metallic substrate and exposing the substrate to extreme conditions capable of corrosion. For this reason, pigments, inhibitors, and other compatible blends are added to the polymer coating formulations to enhance adhesion and protection. To prevent the possible deterioration of inhibitor-spiked polymer coatings, inhibitors are encapsulated through diverse techniques to avoid leakage and to provide a controlled release in response to the corrosion trigger. This review discusses polymer-based coating performance in corrosion-causing environments to protect metals, focusing more on commercial steels, a readily available construction-relevant material used in extensive applications. It further beams a searchlight on advances made on polymer-based coatings that employ metal–organic frameworks (MOFs) as functional additives. MOFs possess a tailorable structure of metal ions and organic linkers and have a large loading capacity, which is crucial for corrosion inhibitor delivery. Results from reviewed works show that polymer-based coatings provide barrier protection against the ingress of corrosive species and offer the chance to add several functions to coatings, further enhancing their anti-corrosion properties. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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21 pages, 16767 KiB

Open AccessReview

Avant-Garde Polymer/Graphene Nanocomposites for Corrosion Protection: Design, Features, and Performance

by Ayesha Kausar, Ishaq Ahmad, M. H. Eisa and Malik Maaza

Corros. Mater. Degrad. 2023, 4(1), 33-53; https://doi.org/10.3390/cmd4010004 - 17 Jan 2023

Cited by 3 | Viewed by 2153

Abstract

Polymeric coatings have been widely selected for the corrosion resistance of metallic surfaces. Both the conducting and non-conducting polymers have been applied for corrosion confrontation. The conducting polymers usually possess high electrical conductivity and corrosion resistance features. On the other hand, non-conducting hydrophobic [...] Read more.

Polymeric coatings have been widely selected for the corrosion resistance of metallic surfaces. Both the conducting and non-conducting polymers have been applied for corrosion confrontation. The conducting polymers usually possess high electrical conductivity and corrosion resistance features. On the other hand, non-conducting hydrophobic polymers have also been used to avert the metal erosion. To improve the corrosion inhibition performance of the polymer coatings, nanocarbon nanofillers have been used as reinforcement. Graphene, especially, has gained an important position in the research on the corrosion-protecting nanocomposite coatings. Here, graphene dispersion and matrix–nanofiller interactions may significantly improve the anti-corrosion performance to protect the underlying metals. The graphene nanofiller may form an interconnecting percolation network in the polymers to support their electrical conductivity and thus their corrosion confrontation characteristics. Further research on the polymer/graphene nanocomposite and its anti-corrosion mechanism may lead to great advancements in this field. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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38 pages, 13011 KiB

Open AccessReview

Corrosion Barrier Coatings: Progress and Perspectives of the Chemical Route

by George Kordas

Corros. Mater. Degrad. 2022, 3(3), 376-413; https://doi.org/10.3390/cmd3030023 - 19 Jul 2022

Cited by 13 | Viewed by 4203

Abstract

Improved corrosion barrier coatings (CBCs) to protect metals will allow future metal structures to operate for extended periods, ensuring improved safety by reducing environmental pollution and maintenance costs. Many production methods and design of corrosion barrier coatings (CBCs) have been developed. This review [...] Read more.

Improved corrosion barrier coatings (CBCs) to protect metals will allow future metal structures to operate for extended periods, ensuring improved safety by reducing environmental pollution and maintenance costs. Many production methods and design of corrosion barrier coatings (CBCs) have been developed. This review focuses only on CBCs made with chemistry techniques. These CBCs can be passive and active with remarkable performance. Today, most of the work focuses on the discovery and application of “smart nanomaterials,” which, if incorporated into “passive CBCs,” will turn them into “active CBCs,” giving them the phenomenon of “self-healing” that extends their service life. Today, many efforts are focused on developing sensors to diagnose corrosion at an early stage and CBCs that self-diagnose the environment and respond on demand. In addition, recent technological developments are reviewed, and a comprehensive strategy is proposed for the faster development of new CBC materials. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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