Materials

Research

13 pages, 5662 KiB

Open AccessArticle

Fluorinated Siloxane Modified Layered Double Hydroxide Sealing Film to Enhance the Corrosion Resistance of Anodic Oxide Film of Fricition Stir Welding Joint of Aluminum Alloys

by Wen Li, Tao Wang, Yang Nan, Shao-Jie Li and Wei-Ping Li

Materials 2022, 15(22), 8105; https://doi.org/10.3390/ma15228105 - 16 Nov 2022

Cited by 2 | Viewed by 1178

Abstract

Aluminum alloys and their welding structures have been widely used in aviation, aerospace, automobiles, ships, and other industrial fields. The non-uniform nature of welding structures of aluminum alloys causes intractable corrosion problems. Anodizing and subsequent sealing processes are common and effective methods to [...] Read more.

Aluminum alloys and their welding structures have been widely used in aviation, aerospace, automobiles, ships, and other industrial fields. The non-uniform nature of welding structures of aluminum alloys causes intractable corrosion problems. Anodizing and subsequent sealing processes are common and effective methods to improve the corrosion resistance of welding structures. However, traditional sealing processes like hot water sealing and potassium dichromate sealing are criticized due to energy consumption or toxicity. In this work, a layered double hydroxide (LDH) sealing process with subsequent fluorinated siloxane modification is proposed to improve the corrosion resistance of the anodic oxide film of friction stir welding joints of typical aluminum alloys. The obtained sealing film with typical lamelliform structures of LDH grows well at the defects of oxidation film and also smoothens the sample surface. The hydrophobicity of the film can separate the corrosive medium from the sample surface and further enhance corrosion resistance. As a result, the corrosion current of the welded sample in 3.5 wt.% NaCl solution plummets about 3~4 orders of magnitude compared to the initial state without anodizing, indicating superior corrosion resistance brought by this method. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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21 pages, 9372 KiB

Open AccessArticle

Influence of Surface Modification of Titanium and Its Alloys for Medical Implants on Their Corrosion Behavior

by Łukasz Pawłowski, Magda Rościszewska, Beata Majkowska-Marzec, Magdalena Jażdżewska, Michał Bartmański, Andrzej Zieliński, Natalia Tybuszewska and Pamela Samsel

Materials 2022, 15(21), 7556; https://doi.org/10.3390/ma15217556 - 27 Oct 2022

Cited by 14 | Viewed by 2268

Abstract

Titanium and its alloys are often used for long-term implants after their surface treatment. Such surface modification is usually performed to improve biological properties but seldom to increase corrosion resistance. This paper presents research results performed on such metallic materials modified by a [...] Read more.

Titanium and its alloys are often used for long-term implants after their surface treatment. Such surface modification is usually performed to improve biological properties but seldom to increase corrosion resistance. This paper presents research results performed on such metallic materials modified by a variety of techniques: direct voltage anodic oxidation in the presence of fluorides, micro-arc oxidation (MAO), pulse laser treatment, deposition of chitosan, biodegradable Eudragit 100 and poly(4-vinylpyridine (P4VP), carbon nanotubes, nanoparticles of TiO₂, and chitosan with Pt (nano Pt) and polymeric dispersant. The open circuit potential, corrosion current density, and potential values were determined by potentiodynamic technique, and microstructures of the surface layers and coatings were characterized by scanning electron microscopy. The results show that despite the applied modifications, the corrosion current density still appears in the region of very low values of some nA/cm². However, almost all surface modifications, designed principally for the improvement of biological properties, negatively influence corrosion resistance. The reasons for observed effects can vary, such as imperfections and permeability of some coatings or accelerated degradation of biodegradable deposits in simulated body fluids during electrochemical testing. Despite that, all coatings can be accepted for biological applications, and such corrosion testing results are presumed not to be of major importance for their applications in medicine. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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20 pages, 5761 KiB

Open AccessArticle

Microstructure and Corrosion Behavior of Sn–Zn Alloys

by Žaneta Gerhátová, Paulína Babincová, Marián Drienovský, Matej Pašák, Ivona Černičková, Libor Ďuriška, Róbert Havlík and Marián Palcut

Materials 2022, 15(20), 7210; https://doi.org/10.3390/ma15207210 - 16 Oct 2022

Cited by 9 | Viewed by 1787

Abstract

In the present work, the microstructure, phase constitution, and corrosion behavior of binary Sn–xZn alloys (x = 5, 9 and 15 wt.%) were investigated. The alloys were prepared by induction melting of Sn and Zn lumps in argon. After melting, the alloys were [...] Read more.

In the present work, the microstructure, phase constitution, and corrosion behavior of binary Sn–xZn alloys (x = 5, 9 and 15 wt.%) were investigated. The alloys were prepared by induction melting of Sn and Zn lumps in argon. After melting, the alloys were solidified to form cast cylinders. The Sn–9Zn alloy had a eutectic microstructure. The Sn–5Zn and Sn–15Zn alloys were composed of dendritic (Sn) or (Zn) and eutectic. The corrosion behavior of the Sn–Zn alloys was studied in aqueous HCl (1 wt.%) and NaCl (3.5 wt.%) solutions at room temperature. Corrosion potentials and corrosion rates in HCl were significantly higher compared to NaCl. The corrosion of the binary Sn–Zn alloys was found to take place by a galvanic mechanism. The chemical composition of the corrosion products formed on the Sn–Zn alloys changed with the Zn weight fraction. Alloys with a higher concentration of Zn (Sn–9Zn, Sn–15Zn) formed corrosion products rich in Zn. The Zn-rich corrosion products were prone to spallation. The corrosion rate in the HCl solution decreased with decreasing weight fraction of Zn. The Sn–5Zn alloy had the lowest corrosion rate. The corrosion resistance in HCl could be considerably improved by reducing the proportion of zinc in Sn–Zn alloys. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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20 pages, 10139 KiB

Open AccessArticle

Production and Characterization of the Third-Generation Oxide Nanotubes on Ti-13Zr-13Nb Alloy

by Bożena Łosiewicz, Sandra Skwarek, Agnieszka Stróż, Patrycja Osak, Karolina Dudek, Julian Kubisztal and Joanna Maszybrocka

Materials 2022, 15(6), 2321; https://doi.org/10.3390/ma15062321 - 21 Mar 2022

Cited by 7 | Viewed by 1883

Abstract

In the group of vanadium-free titanium alloys used for applications for long-term implants, the Ti-13Zr-13Nb alloy has recently been proposed. The production of a porous layer of oxide nanotubes (ONTs) with a wide range of geometries and lengths on the Ti-13Zr-13Nb alloy surface [...] Read more.

In the group of vanadium-free titanium alloys used for applications for long-term implants, the Ti-13Zr-13Nb alloy has recently been proposed. The production of a porous layer of oxide nanotubes (ONTs) with a wide range of geometries and lengths on the Ti-13Zr-13Nb alloy surface can increase its osteoinductive properties and enable intelligent drug delivery. This work concerns developing a method of electrochemical modification of the Ti-13Zr-13Nb alloy surface to obtain third-generation ONTs. The effect of the anodizing voltage on the microstructure and thickness of the obtained oxide layers was conducted in 1 M C₂H₆O₂ + 4 wt% NH₄F electrolyte in the voltage range 5–35 V for 120 min at room temperature. The obtained third-generation ONTs were characterized using SEM, EDS, SKP, and 2D roughness profiles methods. The preliminary assessment of corrosion resistance carried out in accelerated corrosion tests in the artificial atmosphere showed the high quality of the newly developed ONTs and the slight influence of neutral salt spray on their micromechanical properties. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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23 pages, 7382 KiB

Open AccessEditor’s ChoiceArticle

Combined Electrochemical, Raman Analysis and Machine Learning Assessments of the Inhibitive Properties of an 1,3,4-Oxadiazole-2-Thiol Derivative against Carbon Steel Corrosion in HCl Solution

by Simona Varvara, Camelia Berghian-Grosan, Gianina Damian, Maria Popa and Florin Popa

Materials 2022, 15(6), 2224; https://doi.org/10.3390/ma15062224 - 17 Mar 2022

Cited by 5 | Viewed by 1533

Abstract

The inhibiting properties of 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol (PyODT) on the corrosion of carbon steel in 1.0 M HCl solution were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy, Raman spectroscopy, and SEM-EDX analysis. An approach based on machine learning algorithms and Raman data was also applied [...] Read more.

The inhibiting properties of 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol (PyODT) on the corrosion of carbon steel in 1.0 M HCl solution were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy, Raman spectroscopy, and SEM-EDX analysis. An approach based on machine learning algorithms and Raman data was also applied to follow the carbon steel degradation in different experimental conditions. The electrochemical measurements revealed that PyODT behaves as a mixed-type corrosion inhibitor, reaching an efficiency of about 93.1% at a concentration of 5 mM, after 1 h exposure to 1.0 M HCl solution. Due to the molecular adsorption and structural organization of PyODT molecules on the C-steel surface, higher inhibitive effectiveness of about 97% was obtained at 24 h immersion. The surface analysis showed a significantly reduced degradation state of the carbon steel surface in the presence of PyODT due to the inhibitor adsorption revealed by Raman spectroscopy and the presence of N and S atoms in the EDX spectra. The combination of Raman spectroscopy and machine learning algorithms was proved to be a facile and reliable tool for an incipient identification of the corrosion sites on a metallic surface exposed to corrosive environments. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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21 pages, 5244 KiB

Open AccessArticle

Corrosion Behavior of an Mg₂Sn Alloy

by Zuzana Gabalcová, Peter Gogola, Žaneta Gerhátová and Marián Palcut

Materials 2022, 15(6), 2025; https://doi.org/10.3390/ma15062025 - 9 Mar 2022

Cited by 6 | Viewed by 2355

Abstract

In the present work, the corrosion behavior of the Mg₂Sn alloy (Mg_66.7Sn_33.3, concentration in at.%) has been studied. The alloy was prepared from high purity Sn and Mg lumps by induction melting in argon. The alloy was [...] Read more.

In the present work, the corrosion behavior of the Mg₂Sn alloy (Mg_66.7Sn_33.3, concentration in at.%) has been studied. The alloy was prepared from high purity Sn and Mg lumps by induction melting in argon. The alloy was composed of intermetallic Mg₂Sn with a small amount of Mg₂Sn + (Sn) eutectic. The corrosion behavior was studied by hydrogen evolution, immersion, and potentiodynamic experiments. Three aqueous solutions of NaCl (3.5 wt.%), NaOH (0.1 wt.%) and HCl (0.1 wt.%) were chosen as corrosion media. The alloy was found to be cathodic with respect to metallic Mg and anodic with respect to Sn. The corrosion potentials of the Mg₂Sn alloy were −1380, −1498 and −1361 mV vs. sat. Ag/AgCl in HCl, NaCl and NaOH solutions, respectively. The highest corrosion rate of the alloy, 92 mmpy, was found in aqueous HCl. The high corrosion rate was accompanied by massive hydrogen evolution on the alloy’s surface. The corrosion rate was found to decrease sharply with increasing pH of the electrolyte. In the NaOH electrolyte, a passivation of the alloy was observed. The corrosion of the alloy involved a simultaneous oxidation of Mg and Sn. The main corrosion products on the alloy surface were MgSn(OH)₆ and Mg(OH)₂. The corrosion mechanism is discussed and implications for practical applications of the alloy are provided. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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17 pages, 10153 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Corrosion Performance of Extruded and Forged WE43 Mg Alloy

by Guonan Liu, Jilei Xu, Baojing Feng, Jinhui Liu, Dongqing Qi, Wenzhan Huang, Peixu Yang and Shaojun Zhang

Materials 2022, 15(5), 1622; https://doi.org/10.3390/ma15051622 - 22 Feb 2022

Cited by 7 | Viewed by 1914

Abstract

Adjusting the microstructure through the deformation process is one of the ways to improve the properties of Mg alloys. Most studies have focused on the influence of the microstructure after deformation treatment on the mechanical properties of Mg alloys. In this paper, extruded [...] Read more.

Adjusting the microstructure through the deformation process is one of the ways to improve the properties of Mg alloys. Most studies have focused on the influence of the microstructure after deformation treatment on the mechanical properties of Mg alloys. In this paper, extruded and forged Mg-Gd-Y-Nd-Zr alloys were selected to investigate the corrosion performance of two deformed magnesium alloys immersed in 0.6 M NaCl solution using a hydrogen evolution test, a weight loss test, an immersion experiment, and an electrochemical test. The results showed that WE43 alloys undergoing different deformation treatments presented different microstructures, which led to different corrosion behaviors and corrosion resistance. The extruded WE43 alloy showed uniform corrosion, while the forged WE43 alloy suffered severe local galvanic corrosion. Meanwhile, the corrosion rate of the forged WE43 alloy was about four times faster than that of the extruded WE43 alloy. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 5229 KiB

Open AccessEditor’s ChoiceArticle

Corrosion Behavior of Ultrafine-Grained CoCrFeMnNi High-Entropy Alloys Fabricated by High-Pressure Torsion

by Haruka Shimizu, Motohiro Yuasa, Hiroyuki Miyamoto and Kaveh Edalati

Materials 2022, 15(3), 1007; https://doi.org/10.3390/ma15031007 - 27 Jan 2022

Cited by 15 | Viewed by 2571

Abstract

The influence of the nanocrystalline structure produced by severe plastic deformation (SPD) on the corrosion behavior of CoCrFeMnNi alloys with Cr contents ranging from 0 to 20 at.% was investigated in aqueous 0.5 M H₂SO₄ and 3.5% NaCl solutions. The [...] Read more.

The influence of the nanocrystalline structure produced by severe plastic deformation (SPD) on the corrosion behavior of CoCrFeMnNi alloys with Cr contents ranging from 0 to 20 at.% was investigated in aqueous 0.5 M H₂SO₄ and 3.5% NaCl solutions. The resistance to general corrosion and pitting became higher in both the solutions, with higher passivation capability observed with increasing Cr content, and it is believed that the high corrosion resistance of CoCrFeMnNi alloys can be attributed to the incorporation of the Cr element. However, the impact of the nanocrystalline structure produced by SPD on the corrosion behavior was negligibly small. This is inconsistent with reports on nanocrystalline binary Fe–Cr alloys and stainless steels processed by SPD, where grain refinement by SPD results in higher corrosion resistance. The small change in the corrosion behavior with respect to grain refinement is discussed, based on the passivation process of Fe–Cr alloys and on the influence of the core effects of HEAs on the passivation process. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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18 pages, 7939 KiB

Open AccessArticle

Pitting Corrosion Behavior and Surface Microstructure of Copper Strips When Rolled with Oil-in-Water Emulsions

by Xudong Yan and Jianlin Sun

Materials 2021, 14(24), 7911; https://doi.org/10.3390/ma14247911 - 20 Dec 2021

Cited by 1 | Viewed by 2905

Abstract

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. [...] Read more.

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. It was found that the corrosion current densities of the rolled Cu strips increased with accumulated reduction, which also lowered the pitting potentials and weakened their corrosion resistances. Therefore, the corrosive tendency of Cu strips under different rolling reductions (ε) followed the order of ε_0% < ε_20.7% < ε_50.6% < ε_77.3%. The Cu surface easily reacted with chlorine, sulfur, and carbon components from O/W emulsions to generate pitting corrosion. Under the interactive effect of pitting corrosion and stress corrosion, pits expanded along the rolling direction. The aggregation of anions in surface defects, such as dislocations, metastable pits, and microcracks, further accelerated the pitting corrosion of the surface. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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17 pages, 2996 KiB

Open AccessArticle

Quantitative Non-Linear Effect of High Ambient Temperature on Chloride Threshold Value for Steel Reinforcement Corrosion in Concrete under Extreme Boundary Conditions

by Abdulrahman M. Alhozaimy, Mshtaq Ahmed, Raja Rizwan Hussain and Abdulaziz Al-Negheimish

Materials 2021, 14(24), 7595; https://doi.org/10.3390/ma14247595 - 10 Dec 2021

Cited by 2 | Viewed by 2056

Abstract

This paper investigates the effect of high ambient temperatures on the chloride threshold value for reinforced concrete (RC) structures. Two commonly available carbon steel rebars were investigated under four different exposure temperatures (20 °C (68 °F), 35 °C (95 °F), 50 °C (122 [...] Read more.

This paper investigates the effect of high ambient temperatures on the chloride threshold value for reinforced concrete (RC) structures. Two commonly available carbon steel rebars were investigated under four different exposure temperatures (20 °C (68 °F), 35 °C (95 °F), 50 °C (122 °F), and 65 °C (149 °C)) using environmental chambers at a constant relative humidity of 80%. For each temperature, six different levels of added chloride ions (0.00%, 0.15%, 0.30%, 0.60%, 0.90%, and 1.20% by weight of cement) were used to study the chloride threshold value. Corrosion initiation was detected by monitoring the corrosion potential and corrosion rate using electrochemical techniques. The water-soluble (free) and acid-soluble (total) chlorides were determined using potentiometric titration according to the relevant ASTM standards. The threshold chloride content for each exposure temperature was determined by analyzing the corrosion potential, corrosion rate, and chloride content of each specimen. The results showed that the chloride threshold values were significantly temperature-dependent. At temperatures of 20 °C (68 °F) and 35 °C (95 °F), the chloride threshold value (expressed as free chlorides) was approximately 0.95% by weight of cement. However, as the temperature increased to 50 °C (122 °F), the chloride threshold decreased significantly to approximately 0.70% by weight of cement. The reduction in the chloride threshold value became more dramatic at an exposure temperature of 65 °C (149 °F), decreasing to approximately 0.25% by weight of cement. The trends were similar for the rebars from the two sources, indicating that the rebar source had little influence on the chloride threshold value. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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19 pages, 6247 KiB

Open AccessArticle

Role of Coating Processes on the Corrosion Kinetics and Mechanism of Zinc in Artificial Seawater

by Jitendra Kumar Singh, Soumen Mandal, Raihana Jannat Adnin, Han-Seung Lee and Hyun-Min Yang

Materials 2021, 14(23), 7464; https://doi.org/10.3390/ma14237464 - 6 Dec 2021

Cited by 7 | Viewed by 2131

Abstract

Zinc (Zn) coating is being used to protect steel structures from corrosion. There are different processes to deposit the coating onto a steel substrate. Therefore, in the present study, a 100 µm thick Zn coating was deposited by arc and plasma arc thermal [...] Read more.

Zinc (Zn) coating is being used to protect steel structures from corrosion. There are different processes to deposit the coating onto a steel substrate. Therefore, in the present study, a 100 µm thick Zn coating was deposited by arc and plasma arc thermal spray coating processes, and the corrosion resistance performance was evaluated in artificial seawater. Scanning electron microscopy (SEM) results showed that the arc thermal spray coating exhibited splats and inflight particles, whereas plasma arc spraying showed a uniform and dense morphology. When the exposure periods were extended up to 23 d, the corrosion resistance of the arc as well as the plasma arc thermal spray coating increased considerably. This is attributed to the blocking characteristics of the defects by the stable hydrozincite (Zn₅(OH)₆(CO₃)₂). Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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18 pages, 5522 KiB

Open AccessArticle

Wear and Corrosion Resistance of AlSi10Mg–CP–Ti Metal–Metal Composite Materials Produced by Electro-Sinter-Forging

by Federico Simone Gobber, Elisa Fracchia, Roberto Spotorno, Alessandro Fais and Diego Manfredi

Materials 2021, 14(22), 6761; https://doi.org/10.3390/ma14226761 - 10 Nov 2021

Cited by 3 | Viewed by 2101

Abstract

Metal–metal composites are a class of composite materials studied for their high ductility and strength, but their potential applications are currently limited by the complex manufacturing processes involved. Electro-sinter-forging (ESF) is a single-pulse electro discharge sintering technique that proved its effectiveness in the [...] Read more.

Metal–metal composites are a class of composite materials studied for their high ductility and strength, but their potential applications are currently limited by the complex manufacturing processes involved. Electro-sinter-forging (ESF) is a single-pulse electro discharge sintering technique that proved its effectiveness in the rapid sintering of several metals, alloys, and composites. Previous studies proved the processability of Ti and AlSi10Mg by ESF to produce metal–metal composites and defined a correlation between microstructure and processing parameters. This paper presents the wear and corrosion characterizations of two metal–metal composites obtained via ESF with the following compositions: 20% Ti/80% AlSi10Mg and 20% AlSi10Mg/80% Ti. The two materials showed complementary resistance to wear and corrosion. A higher fraction of AlSi10Mg is responsible for forming a protective tribolayer in dry-sliding conditions, while a higher fraction of Titanium confers improved corrosion resistance due to its higher corrosion potential. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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16 pages, 6713 KiB

Open AccessArticle

Enhanced Long-Term Reliability of Seal DeltaSpot Welded Dissimilar Joint between 6061 Aluminum Alloy and Galvannealed Steel via Excimer Laser Irradiation

by Sung-Min Joo, Young-Gon Kim, Young-Jin Kwak, Dong Jin Yoo, Chang-U Jeong, Jeshin Park and Min-Suk Oh

Materials 2021, 14(22), 6756; https://doi.org/10.3390/ma14226756 - 9 Nov 2021

Cited by 5 | Viewed by 1694

Abstract

Structural-adhesive-assisted DeltaSpot welding was used to improve the weldability and mechanical properties of dissimilar joints between 6061 aluminum alloy and galvannealed HSLA steel. Evaluation of the spot-weld-bonded surfaces from lap shear tests after long-term exposure to chloride and a humid atmosphere (5% NaCl, [...] Read more.

Structural-adhesive-assisted DeltaSpot welding was used to improve the weldability and mechanical properties of dissimilar joints between 6061 aluminum alloy and galvannealed HSLA steel. Evaluation of the spot-weld-bonded surfaces from lap shear tests after long-term exposure to chloride and a humid atmosphere (5% NaCl, 35 °C) indicated that the long-term mechanical reliability of the dissimilar weld in a corrosive environment depends strongly on the adhesive–Al6061 alloy bond strength. Corrosive electrolyte infiltrated the epoxy-based adhesive/Al alloy interface, disrupting the chemical interactions and decreasing the adhesion via anodic undercutting of the Al alloy. Due to localized electrochemical galvanic reactions, the surrounding nugget matrix suffered accelerated anodic dissolution, resulting in an Al6061-T6 alloy plate with degraded adhesive strength and mechanical properties. KrF excimer laser irradiation of the Al alloy before adhesive bonding removed the weakly bonded native oxidic overlayers and altered the substrate topography. This afforded a low electrolyte permeability and prevented adhesive delamination, thereby enhancing the long-term stability of the chemical interactions between the adhesive and Al alloy substrate. The results demonstrate the application of excimer laser irradiation as a simple and environmentally friendly processing technology for robust adhesion and reliable bonding between 6061 aluminum alloy and galvannealed steel. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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18 pages, 5097 KiB

Open AccessArticle

Effect of Chloride Ions Concentrations to Breakdown the Passive Film on Rebar Surface Exposed to L-Arginine Containing Pore Solution

by Jitendra Kumar Singh, Soumen Mandal, Han-Seung Lee and Hyun-Min Yang

Materials 2021, 14(19), 5693; https://doi.org/10.3390/ma14195693 - 30 Sep 2021

Cited by 3 | Viewed by 1565

Abstract

In the present study, 0.115 M L-arginine (LA) has been used as an eco-friendly inhibitor in simulated concrete pore solutions (SP-0) in order to form passive films on a steel rebar–solution interface until 144 h. Hence, 0.51 (SP-1) and 0.85 M NaCl (SP-2) [...] Read more.

In the present study, 0.115 M L-arginine (LA) has been used as an eco-friendly inhibitor in simulated concrete pore solutions (SP-0) in order to form passive films on a steel rebar–solution interface until 144 h. Hence, 0.51 (SP-1) and 0.85 M NaCl (SP-2) were added in LA containing SP-0 solution to breakdown the passive film and to initiate corrosion reactions. The electrochemical results show that the charge transfer resistance (R_ct) of steel rebar exposed to SP-1 and SP-2 solutions increased with respect to immersion periods. The sample exposed to the SP-2 solution initiated the corrosion reaction at the steel rebar–solution interface after 24 h of NaCl addition and formed pits; on the other hand, the sample without NaCl added, i.e., SP-0, showed agglomeration and dense morphology of corrosion products. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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11 pages, 3855 KiB

Open AccessArticle

Corrosion Behavior of Niobium-Coated 316L Stainless Steels as Metal Bipolar Plates for Polymer Electrolyte Membrane Fuel Cells

by Yu-Sung Kim, In-Sik Lee, Jin-Young Choi, Shinhee Jun, Daeil Kim, Byung-Chul Cha and Dae-Wook Kim

Materials 2021, 14(17), 4972; https://doi.org/10.3390/ma14174972 - 31 Aug 2021

Cited by 13 | Viewed by 2101

Abstract

Niobium was coated on 316L stainless steel by pulsed direct-current (DC) magnetron sputtering to improve corrosion behavior. The applied bias voltage highly affected the microstructure and crystallographic features, which lead to improved corrosion behavior. Due to the increased bias voltage, the microstructure of [...] Read more.

Niobium was coated on 316L stainless steel by pulsed direct-current (DC) magnetron sputtering to improve corrosion behavior. The applied bias voltage highly affected the microstructure and crystallographic features, which lead to improved corrosion behavior. Due to the increased bias voltage, the microstructure of the niobium coating layer presented a smaller crystallite size and a densified structure, which obviously reduced the number of pinholes in the coated layer. Additionally, an increase in the degree of orientation toward the (110) plane, the most densely packed plane, lead to reduced dissolution of metal ions. Therefore, a pure niobium coating layer effectively protected the metal bipolar plate from a highly corrosive environment of polymer electrolyte membrane fuel cell (PEMFC) stacks. In particular, higher bias voltages of 600 and 800 V induced improved corrosion resistance, which satisfied the demand for the bipolar plate. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 3835 KiB

Open AccessArticle

Effect of Imidazole as Corrosion Inhibitor on Carbon Steel Weldment in District Heating Water

by Sang-Jin Ko, Seok-Ryul Choi, Min-Sung Hong, Woo-Cheol Kim and Jung-Gu Kim

Materials 2021, 14(16), 4416; https://doi.org/10.3390/ma14164416 - 6 Aug 2021

Cited by 7 | Viewed by 2673

Abstract

Many research studies have been conducted on the corrosion inhibition performance of imidazole in acidic environments such as in the piping of a petrochemical plant. However, there has been no study on the effect of imidazole in alkaline conditions such as a local [...] Read more.

Many research studies have been conducted on the corrosion inhibition performance of imidazole in acidic environments such as in the piping of a petrochemical plant. However, there has been no study on the effect of imidazole in alkaline conditions such as a local district water heating environment. Therefore, in this study, the effect of imidazole as a corrosion inhibitor on carbon steel weldment was investigated in alkaline district heating water. Inhibition efficiency and electrochemical properties were investigated by potentiodynamic polarization test and electrochemical impedance spectroscopy. As the concentration of imidazole increased up to 500 ppm, inhibition efficiency increased up to 91.7%. At 1000 ppm, inhibition efficiency decreased. Atomic force microscopy showed that surface coverage of imidazole at 1000 ppm is lower than that of imidazole at 500 ppm. X-ray photoelectron spectroscopy showed that with 500 ppm of imidazole, the amount of pyrrole type interaction is 4.8 times larger than pyridine type interaction. At 1000 ppm of imidazole, the amount of pyridine type interaction is 3.49 times larger than pyrrole type interaction. Depending on the concentration of imidazole, the ratio of interaction between carbon steel and imidazole affected inhibition efficiency. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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15 pages, 41229 KiB

Open AccessArticle

Effects of Zinc Addition on the Corrosion Behavior of Pre-Filmed Alloy 690 in Borated and Lithiated Water at 330 °C

by Soon-Hyeok Jeon, Dong-Seok Lim, Jinsoo Choi, Kyu-Min Song, Jong-Hyeon Lee and Do-Haeng Hur

Materials 2021, 14(15), 4105; https://doi.org/10.3390/ma14154105 - 23 Jul 2021

Cited by 4 | Viewed by 1654

Abstract

The purpose of this work is to quantify the effects of dissolved zinc cations on corrosion and release rates from a pre-filmed Alloy 690 steam generator tubing material that was subsequently exposed to water containing zinc. The corrosion tests were performed in circulating [...] Read more.

The purpose of this work is to quantify the effects of dissolved zinc cations on corrosion and release rates from a pre-filmed Alloy 690 steam generator tubing material that was subsequently exposed to water containing zinc. The corrosion tests were performed in circulating 2 ppm Li and 1000 ppm B water without and with 60 ppb zinc at 330 °C. Gravimetric analyses and oxide characterization revealed that the corrosion rates, release rates, and oxide thicknesses decreased by subsequent exposure of the pre-filmed Alloy 690 to zinc. These benefits are attributed to the formation of a chromium-rich inner oxide layer incorporating zinc. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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15 pages, 6136 KiB

Open AccessArticle

Influence of the Nb and V Addition on the Microstructure and Corrosion Resistance of the Fe-B-Co-Si Alloy

by Rafał Mech, Jolanta Gąsiorek, Amadeusz Łaszcz and Bartosz Babiarczuk

Materials 2021, 14(14), 4045; https://doi.org/10.3390/ma14144045 - 20 Jul 2021

Cited by 4 | Viewed by 2000

Abstract

The paper presents a comparison of the results of the corrosion resistance for three Fe-B-Co-Si-based newly developed alloys with the addition of Nb and V. The corrosion performance differences and microstructure variations were systematically studied using scanning electron microscope, electric corrosion equipment, X-ray [...] Read more.

The paper presents a comparison of the results of the corrosion resistance for three Fe-B-Co-Si-based newly developed alloys with the addition of Nb and V. The corrosion performance differences and microstructure variations were systematically studied using scanning electron microscope, electric corrosion equipment, X-ray diffractometer, and differential calorimeter. It has been shown that each alloying addition increased the corrosion resistance. The highest corrosion resistance obtained by potentiodynamic polarization was found for the alloy with both Nb and V addons (Fe₅₇Co₁₀B₂₀Si₅Nb₄V₄) and lowest in the case of the basic four-element Fe₆₂Co₁₅B₁₄Si₉ material. This shows that the proper choice of additions is of significant influence on the final performance of the alloy and allows tailoring of the material for specific applications. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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14 pages, 5679 KiB

Open AccessArticle

Enhancing the Corrosion Resistance of Austenitic Steel Using Active Screen Plasma Nitriding and Nitrocarburising

by Tomasz Borowski

Materials 2021, 14(12), 3320; https://doi.org/10.3390/ma14123320 - 15 Jun 2021

Cited by 16 | Viewed by 2106

Abstract

AISI 316L steel was subjected to active screen plasma nitriding and nitrocarburising. The processes were carried out at 440 °C for 6 h. The nitriding process employed an atmosphere of nitrogen and hydrogen, while nitrocarburising was carried out in nitrogen, hydrogen and methane. [...] Read more.

AISI 316L steel was subjected to active screen plasma nitriding and nitrocarburising. The processes were carried out at 440 °C for 6 h. The nitriding process employed an atmosphere of nitrogen and hydrogen, while nitrocarburising was carried out in nitrogen, hydrogen and methane. The processes yielded structures consisting of nitrogen and nitro-carbon expanded austenite, respectively. Microhardness was measured via the Vickers method, surface roughness using an optical profilometer, microstructure by means of light microscopy, while a scanning electron microscope (SEM) served to determine surface topography. Phase composition, lattice parameter and lattice deformation tests were carried out using the X-ray diffraction (XRD) method. Corrosion resistance measurements were performed in a 0.5 M NaCl solution using the potentiodynamic method. The produced layers showed very high resistance to pitting corrosion, while the pitting potential reached 1.5 V, a value that has not yet been recorded in a chloride environment. After the passive layer was broken down, there was a clear deceleration of pitting in the nitrocarburised layer. It was found that in the case of nitro-carbon expanded austenite, pits are formed much slower compared to the nitrogen austenite layer. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 4713 KiB

Open AccessArticle

Effect of the Alloying Metal on the Corrosion Resistance of Pd-Rich Binary Alloys with Pt, Rh, and Ru in Sulfuric Acid

by Katarzyna Hubkowska, Julian Kubisztal, Małgorzata Pająk, Bożena Łosiewicz and Andrzej Czerwiński

Materials 2021, 14(11), 2923; https://doi.org/10.3390/ma14112923 - 28 May 2021

Cited by 6 | Viewed by 2205

Abstract

The paper presents the study of the corrosion resistance of electrodeposited Pd and its binary alloys with Pt, Rh, and Ru on a polycrystalline Au substrate. The corrosion resistance was tested in 0.5 M sulfuric acid at room temperature using potentiodynamic polarization and [...] Read more.

The paper presents the study of the corrosion resistance of electrodeposited Pd and its binary alloys with Pt, Rh, and Ru on a polycrystalline Au substrate. The corrosion resistance was tested in 0.5 M sulfuric acid at room temperature using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The morphology/composition and work function values were determined by scanning electron microscopy/energy–dispersive X–ray spectroscopy and scanning Kelvin probe, respectively. The obtained results revealed that the Pd electrode is the most resistant to corrosion, whereas the Pd-Ru electrode is the most susceptible to dissolution. It was found that the corrosion resistance of Pd-binary alloys decrease in the following order: Pd > Pd-Pt > Pd-Rh > Pd-Ru. This effect was assigned mainly to the difference in surface roughness factor of tested electrodes. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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15 pages, 6621 KiB

Open AccessArticle

Effect of Benzotriazole on the Localized Corrosion of Copper Covered with Carbonaceous Residue

by Yun-Ho Lee, Min-Sung Hong, Sang-Jin Ko and Jung-Gu Kim

Materials 2021, 14(11), 2722; https://doi.org/10.3390/ma14112722 - 21 May 2021

Cited by 13 | Viewed by 2601

Abstract

Carbonaceous residues on copper pipes during the manufacturing process are known to be one of the main causes of pitting corrosion on copper pipes. This study examined the corrosion-inhibiting effect of benzotriazole (BTA) on C12200 copper pipes with carbonaceous film in synthetic tap [...] Read more.

Carbonaceous residues on copper pipes during the manufacturing process are known to be one of the main causes of pitting corrosion on copper pipes. This study examined the corrosion-inhibiting effect of benzotriazole (BTA) on C12200 copper pipes with carbonaceous film in synthetic tap water. In the absence of BTA, localized corrosion mechanisms due to galvanic corrosion, crevice corrosion, and oxygen-concentration cell were proposed in the boundary part of the carbonaceous film on the copper through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) analyses. Electrochemical tests showed that BTA inhibits corrosion by forming Cu−BTA complexes on all over the copper surface where carbonaceous film is present. BTA mitigates galvanic corrosion and crevice corrosion at the boundary of the carbonaceous film and suppresses the formation of oxygen-concentration cells through the formation of a Cu−BTA complex. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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10 pages, 18138 KiB

Open AccessArticle

Study on the Purity of Gold Leaf in a SO₂ Atmosphere at Ambient Temperature

by Houyi Huang, Guanglin Xu and Xinyou Liu

Materials 2021, 14(9), 2425; https://doi.org/10.3390/ma14092425 - 6 May 2021

Cited by 3 | Viewed by 1867

Abstract

Gold leaf samples of different purities were corroded in a SO₂ atmosphere at three different relative humidities (30%, 60%, 90%) at ambient temperature, and the effects on color, gloss, and morphology were studied. Results showed that a corrosion rate of 0.0898 g/cm [...] Read more.

Gold leaf samples of different purities were corroded in a SO₂ atmosphere at three different relative humidities (30%, 60%, 90%) at ambient temperature, and the effects on color, gloss, and morphology were studied. Results showed that a corrosion rate of 0.0898 g/cm² could be attained after 6 weeks at high humidity. Color changes also occurred during the gold leaf corrosion process, and many thin pits formed on the surfaces, as shown by SEM. EDX results showed that these pits contained C, O, and S compounds. By comparing the results of different gold purity samples and different relative humidity conditions, it could be concluded that both gold content and humidity play an important role in SO₂ atmosphere corrosion. These conclusions are helpful for the conservation of gold leaf decorative cultural relics. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 3642 KiB

Open AccessArticle

Innovative Method for Coating of Natural Corrosion Inhibitor Based on Artemisia vulgaris

by Daniel Alejandro Pineda Hernández, Elisabeth Restrepo Parra, Pedro José Arango Arango, Belarmino Segura Giraldo and Carlos Daniel Acosta Medina

Materials 2021, 14(9), 2234; https://doi.org/10.3390/ma14092234 - 26 Apr 2021

Cited by 11 | Viewed by 2235

Abstract

In this work, the production of a novel methodology for the application of natural corrosion inhibitors on steel, using an autoclave is presented. Tests were carried out using Artemisia vulgaris. The inhibitor was produced with a simple soxhlet extraction process using 15 [...] Read more.

In this work, the production of a novel methodology for the application of natural corrosion inhibitors on steel, using an autoclave is presented. Tests were carried out using Artemisia vulgaris. The inhibitor was produced with a simple soxhlet extraction process using 15 g of Artemisia vulgaris and 260 mL of Ether. Once the inhibitor was produced, the steel was immersed in it, to form a coating that protects the material against corrosion. Thermogravimetry analyzes (TGA) were performed on the inhibitor, to determine the degradation temperature; it was observed that, at 321 °C, the loss of organic mass begins. After applying the inhibitor to the steel, the Fourier Transform Infrared Spectroscopy (FTIR) technique was used to determine the vibrational bands and the difference between the spectra for the steels before and after the coating was applied. For the evaluation of the method efficiency, Electrochemical Impedance Spectroscopy (EIS) and polarization resistance tests were performed, where Nyquist diagrams and Tafel curves were obtained, for steels with and without treatment. In this case, an increase of 93% in the corrosion resistance, and an 88% decrease in the corrosion rate were observed, proving that this methodology can be used to protect steel against corrosion and extend the steel’s useful life. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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16 pages, 9549 KiB

Open AccessArticle

Electrodeposition of Copper and Brass Coatings with Olive-Like Structure

by Artur Maciej, Natalia Łatanik, Maciej Sowa, Izabela Matuła and Wojciech Simka

Materials 2021, 14(7), 1762; https://doi.org/10.3390/ma14071762 - 2 Apr 2021

Cited by 4 | Viewed by 2127

Abstract

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a [...] Read more.

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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18 pages, 6173 KiB

Open AccessArticle

Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy

by Maciej Sowa, Marta Wala, Agata Blacha-Grzechnik, Artur Maciej, Alicja Kazek-Kęsik, Agnieszka Stolarczyk and Wojciech Simka

Materials 2021, 14(3), 619; https://doi.org/10.3390/ma14030619 - 29 Jan 2021

Cited by 8 | Viewed by 2270

Abstract

There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step [...] Read more.

There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step method of oxide layer formation on 6061-T651 aluminum alloy (AAs) via alternating current (AC) plasma electrolytic oxidation (PEO), impregnation with an 8-hydroxyquinoline (8-HQ) solution, and final sealing by an additional direct current (DC) polarization in the original PEO electrolyte. The obtained coatings were characterized by scanning electron microscopy, roughness tests, contact angle measurements, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Additionally, corrosion resistance was assessed by potentiodynamic polarization in a NaCl solution. Two types of the coating were formed (A—thicker, more porous at 440 mA cm⁻²; B—thinner, more compact at 220 mA cm⁻²) on the AA substrate. The 8-HQ impregnation was successful as evidenced by XPS. It increased the contact angle only for the B coatings and improved the corrosion resistance of both coating systems. Additional DC treatment destroyed superficially adsorbed 8-HQ. However, it served to block the coating pores (contact angle ≈ 80°) which improved the corrosion resistance of the coating systems. DC sealing alone did not bring about the same anti-corrosion properties as the combined 8-HQ impregnation and DC treatment which dispels the notion that the provision of the inhibitor was a needless step in the procedure. The proposed method of AA surface treatment suffered from unsatisfactory uniformity of the sealing for the thicker coatings, which needs to be amended in future efforts for optimization of the procedure. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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18 pages, 5260 KiB

Open AccessArticle

Corrosion Resistance of the CpTi G2 Cellular Lattice with TPMS Architecture for Gas Diffusion Electrodes

by Bożena Łosiewicz, Joanna Maszybrocka, Julian Kubisztal, Grzegorz Skrabalak and Andrzej Stwora

Materials 2021, 14(1), 81; https://doi.org/10.3390/ma14010081 - 26 Dec 2020

Cited by 12 | Viewed by 2304

Abstract

The corrosion of materials used in the design of metal-air batteries may shorten their cycle life. Therefore, metal-based materials with enhanced electrochemical stability have attracted much attention. The purpose of this work was to determine the corrosion resistance of commercially pure titanium Grade [...] Read more.

The corrosion of materials used in the design of metal-air batteries may shorten their cycle life. Therefore, metal-based materials with enhanced electrochemical stability have attracted much attention. The purpose of this work was to determine the corrosion resistance of commercially pure titanium Grade 2 (CpTi G2) cellular lattice with the triply periodic minimal surfaces (TPMS) architecture of G80, D80, I-2Y80 in 0.1 M KOH solution saturated with oxygen at 25 °C. To produce CpTi G2 cellular lattices, selective laser melting technology was used which allowed us to obtain 3D cellular lattice structures with a controlled total porosity of 80%. For comparison, the bulk electrode was also investigated. SEM examination and statistical analysis of the surface topography maps of the CpTi G2 cellular lattices with the TPMS architecture revealed much more complex surface morphology compared to the bulk CpTi SLM. Corrosion resistance tests of the obtained materials were conducted using open circuit potential method, Tafel curves, anodic polarization curves, and electrochemical impedance spectroscopy. The highest corrosion resistance and the lowest material consumption per year were revealed for the CpTi G2 cellular lattice with TPMS architecture of G80, which can be proposed as promising material with increased corrosion resistance for gas diffusion in alkaline metal-air batteries. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 4497 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Microstructural Changes on Mechanical and Electrochemical Corrosion Properties of Duplex Stainless Steel Aged for Short Periods

by David D. S. Silva, Lindolpho S. D. C. Lima, Allan J. M. Araújo, Vinícius D. Silva, Rafael A. Raimundo, Igor Z. Damasceno, Thiago A. Simões and Rodinei M. Gomes

Materials 2020, 13(23), 5511; https://doi.org/10.3390/ma13235511 - 3 Dec 2020

Cited by 11 | Viewed by 2983

Abstract

This work reports the effects of microstructural changes due to the secondary phases, in particular sigma (σ), on the mechanical properties and electrochemical behavior of thermally aged duplex stainless steel (DSS). Structural, morphological, mechanical, and electrochemical characterizations were performed. Sigma phase [...] Read more.

This work reports the effects of microstructural changes due to the secondary phases, in particular sigma (σ), on the mechanical properties and electrochemical behavior of thermally aged duplex stainless steel (DSS). Structural, morphological, mechanical, and electrochemical characterizations were performed. Sigma phase content increased with increasing aging treatment time. It had a net-like shape, as observed by electron backscatter diffractometry (EBSD). Its presence directly damaged mechanical properties. The corrosion assessment included electrochemical impedance spectroscopy (EIS) in 1 M NaCl solution at temperatures of 25, 40, and 65 °C. EIS results demonstrate that an increase in the σ phase content decreased the corrosion resistance (21.1–0.8, 3.5–0.3, and 3.1–0.2 kΩ cm² at 25, 40, and 60 °C, respectively). Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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19 pages, 5828 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Analysis of the Calcium Phosphate-Based Hybrid Layer Formed on a Ti-6Al-7Nb Alloy to Enhance the Ossseointegration Process

by Alicja Kazek-Kęsik, David Djurado, Stéphanie Pouget, Agata Blacha-Grzechnik, Izabela Kalemba-Rec and Wojciech Simka

Materials 2020, 13(23), 5468; https://doi.org/10.3390/ma13235468 - 30 Nov 2020

Cited by 8 | Viewed by 1888

Abstract

This paper reports on hybrid, bioactive ceramic Ca-P-based coating formation on a Ti-6Al-7Nb alloy substrate to enhance the osseointegration process. The Ti alloy was anodized in a Ca₃(PO₄)₂ suspension and then the additional layer was formed by the [...] Read more.

This paper reports on hybrid, bioactive ceramic Ca-P-based coating formation on a Ti-6Al-7Nb alloy substrate to enhance the osseointegration process. The Ti alloy was anodized in a Ca₃(PO₄)₂ suspension and then the additional layer was formed by the sol-gel technique to obtain a mixture of the calcium phosphate compounds. The oxide layer was porous and additional ceramic particles were formed after sol-gel treatment (scanning electron microscopy analysis coupled with energy-dispersive x-ray spectroscopy). The ceramic particles were formed on some parts of the oxide layer and did not completely fill the pores. The layer thickness of the anodized Ti alloy was comprised between 3.01 and 5.03 µm and increased to 7.52–12.30 µm after the formation of an additional layer. Post-treatment of the anodized Ti alloys caused a decrease in surface roughness, and the layer became strongly hydrophilic. Crystalline phase analysis (X-ray diffraction, XRD) showed that the hybrid layer was composed of TiO₂ (anatase), Ca₃(PO₄)₂, Ca₁₀(PO₄)₆(OH)₂ and a partially amorphous phase; thus, the layer was also analyzed by Raman spectroscopy. The hybrid layer showed worse adhesion to the substrate than the anodized layer only; however, the coating was not brittle, and the first delamination of the layer was determined at 1.84 ± 0.11 N during scratch-test measurement. The hybrid coating was favorable for collagen type I and lactoferrin adsorption, strongly influencing the proliferation of osteoblast-like MG-63 cells. The coatings were cytocompatible and may find applications in formation of the functional layers on long-term implants’ surface after. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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15 pages, 10322 KiB

Open AccessArticle

Effects of Sodium Phosphate and Sodium Nitrite on the Pitting Corrosion Process of X70 Carbon Steel in Sodium Chloride Solution

by Yongyan Zhu, Jiayi Ding, Jianli Zhang and Liang Li

Materials 2020, 13(23), 5392; https://doi.org/10.3390/ma13235392 - 27 Nov 2020

Cited by 5 | Viewed by 2037

Abstract

In this paper, effects of sodium phosphate (Na₃PO₄) and sodium nitrite (NaNO₂) on the pitting corrosion of X70 carbon steel in 0.10 mol/L NaCl solution were investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy (EIS) method, scanning [...] Read more.

In this paper, effects of sodium phosphate (Na₃PO₄) and sodium nitrite (NaNO₂) on the pitting corrosion of X70 carbon steel in 0.10 mol/L NaCl solution were investigated by potentiodynamic polarization technique, electrochemical impedance spectroscopy (EIS) method, scanning electron microscope (SEM) and scanning electrochemical microscope (SECM). The SECM equipment was used to observe the dynamic processes of the pitting corrosion in situ. Na₃PO₄ or NaNO₂ in the sodium chloride solution decreased the local anodic dissolution and increased the pitting resistance of the specimen. By analysis and comparison, it can be concluded that the inhibition effect of Na₃PO₄ is mainly due to the formation of a salt film, while the corrosion inhibition of NaNO₂ is principally attributed to a protective oxide film on the electrode surface. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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16 pages, 8706 KiB

Open AccessArticle

The Importance of Phase Composition for Corrosion Resistance of Borided Layers Produced on Nickel Alloys

by Natalia Makuch

Materials 2020, 13(22), 5131; https://doi.org/10.3390/ma13225131 - 13 Nov 2020

Cited by 13 | Viewed by 2502

Abstract

The plasma paste boriding process was used for production of the borided layers on pure nickel and nickel-chromium alloys. The produced layers consisted of nickel borides only (in the case of nickel) or a nickel and chromium borides mixture (in the case Ni–Cr [...] Read more.

The plasma paste boriding process was used for production of the borided layers on pure nickel and nickel-chromium alloys. The produced layers consisted of nickel borides only (in the case of nickel) or a nickel and chromium borides mixture (in the case Ni–Cr alloys). The objective of this investigation was to indicate the importance of the presence of chromium for corrosion resistance of non-borided alloys, as well as to indicate the influence of phase composition of borided layers on their corrosion resistance. Pure nickel was characterized by higher corrosion resistance, in comparison to the nickel-based alloys. Increased chromium content in nickel alloys resulted in their high susceptibility for pitting corrosion. All borided samples were characterized by higher corrosion resistance than the non-borided samples. However, the phase composition of borided layers influenced their corrosion resistance. Due to the microstructure which consisted of one type of borides (nickel borides), borided nickel had the highest resistance to corrosion, whereas the presence of chromium borides in layers produced on nickel-chromium alloys caused a decrease in corrosion resistance. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 3963 KiB

Open AccessArticle

Effect of SiO₂–Al₂O₃ Glass Composite Coating on the Oxidation Behavior of Ti60 Alloy

by Wenbo Li, Ken Chen, Lanlan Liu, Yingfei Yang and Shenglong Zhu

Materials 2020, 13(22), 5085; https://doi.org/10.3390/ma13225085 - 11 Nov 2020

Cited by 6 | Viewed by 1565

Abstract

A SiO₂–Al₂O₃ glass composite coating was prepared on Ti60 alloy via air spraying slurry and then a suitable baking process. It was composed of potassium silicate glass, alumina and quartz powders. The high temperature oxidation performance of the [...] Read more.

A SiO₂–Al₂O₃ glass composite coating was prepared on Ti60 alloy via air spraying slurry and then a suitable baking process. It was composed of potassium silicate glass, alumina and quartz powders. The high temperature oxidation performance of the alloy with and without coating was evaluated in static air at both 800 °C and 900 °C. The results show that catastrophic oxidation occurs for Ti60 bare alloy. It had a mass gain of about 2 mg/cm² after oxidation at 800 °C and 17 mg/cm² at 900 °C for 100 h. On the contrary, the oxidation resistance of alloy coated with composite coating was much improved with the mass gain about 0.36 mg/cm² and 0.95 mg/cm² at 800 °C and at 900 °C, respectively. The microstructure evolution of the composite coating and the alloy was analyzed by scanning electron microscope and electron probe microanalyzer. The effect of the composite coating on the oxidation performance of the alloy is discussed especially in terms of oxygen diffusion and interfacial reaction. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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26 pages, 7910 KiB

Open AccessArticle

Effect of Autoclaving Time on Corrosion Resistance of Sandblasted Ti G4 in Artificial Saliva

by Bożena Łosiewicz, Patrycja Osak, Joanna Maszybrocka, Julian Kubisztal and Sebastian Stach

Materials 2020, 13(18), 4154; https://doi.org/10.3390/ma13184154 - 18 Sep 2020

Cited by 20 | Viewed by 2432

Abstract

Titanium Grade 4 (Ti G4) is the most commonly used material for dental implants due to its excellent mechanical properties, chemical stability and biocompatibility. A thin, self-passive oxide layer with protective properties to corrosion is formed on its surface. However, the spontaneous TiO [...] Read more.

Titanium Grade 4 (Ti G4) is the most commonly used material for dental implants due to its excellent mechanical properties, chemical stability and biocompatibility. A thin, self-passive oxide layer with protective properties to corrosion is formed on its surface. However, the spontaneous TiO₂ layer is chemically unstable. In this work, the impact of autoclaving time on corrosion resistance of Ti G4 in artificial saliva solution with pH = 7.4 at 37 °C was studied. Ti G4 was sandblasted with white Al₂O₃ particles and autoclaved for 30–120 min. SEM, EDS, 2D roughness profiles, confocal laser scanning microscopy, and a Kelvin scanning probe were used for the surface characterization of the Ti G4 under study. In vitro corrosion resistance tests were conducted using open circuit potential, polarization curves, and electrochemical impedance spectroscopy measurements. It was found that Sa parameter, electron work function, and thickness of the oxide layers, determined based on impedance measurements, increased after autoclaving. The capacitive behavior and high corrosion resistance of tested materials were revealed. The improvement in the corrosion resistance after autoclaving was due to the presence of oxide layers with high chemical stability. The optimal Ti G4 surface for dentistry can be obtained by sandblasting with Al₂O₃ with an average grain size of 53 µm, followed by autoclaving for 90 min. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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24 pages, 3960 KiB

Open AccessArticle

Effect of Phosphate-Based Inhibitor on Corrosion Kinetics and Mechanism for Formation of Passive Film onto the Steel Rebar in Chloride-Containing Pore Solution

by Soumen Mandal, Jitendra Kumar Singh, Dong-Eun Lee and Taejoon Park

Materials 2020, 13(16), 3642; https://doi.org/10.3390/ma13163642 - 17 Aug 2020

Cited by 25 | Viewed by 3818

Abstract

In the present study, different contents, i.e., 1–3% of 0.5 M ammonium phosphate mono basic (APMB), were used as corrosion inhibitor to reduce the corrosion of steel rebar. Electrochemical impedance spectroscopy (EIS) results showed that up to 24 h of exposure, polarization resistance [...] Read more.

In the present study, different contents, i.e., 1–3% of 0.5 M ammonium phosphate mono basic (APMB), were used as corrosion inhibitor to reduce the corrosion of steel rebar. Electrochemical impedance spectroscopy (EIS) results showed that up to 24 h of exposure, polarization resistance (R_p) and passive/oxide film resistance (R_o) gradually decreased in simulated concrete pore (SCP) + 3.5 wt.% NaCl solution owing to the reduction in pH of the solution. The steel rebar exposed in 2% inhibitor containing SCP + 3.5 wt.% NaCl solution exhibited 90% inhibition efficiency after 1 h of exposure. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the formation of thermodynamically very stable and sparingly soluble goethite (α-FeOOH), maghemite (γ-Fe₂O₃), and iron phosphate (FePO₄) as passive/oxide film onto the steel rebar surface exposed to 2% inhibitor containing SCP + 3.5 wt.% NaCl solution. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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28 pages, 9947 KiB

Open AccessArticle

Dissolution of Metals in Different Bromide-Based Systems: Electrochemical Measurements and Spectroscopic Investigations

by Simona Varvara, Sorin-Aurel Dorneanu, Alexandru Okos, Liana Maria Muresan, Roxana Bostan, Maria Popa, Daniel Marconi and Petru Ilea

Materials 2020, 13(16), 3630; https://doi.org/10.3390/ma13163630 - 17 Aug 2020

Cited by 8 | Viewed by 3080

Abstract

The dissolution of the main metals (Cu, Zn, Sn, Pb and Fe) found in waste printed circuit boards (WPCBs) was investigated by electrochemical corrosion measurements (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)) in different bromide-based systems that could be used as lixiviants in [...] Read more.

The dissolution of the main metals (Cu, Zn, Sn, Pb and Fe) found in waste printed circuit boards (WPCBs) was investigated by electrochemical corrosion measurements (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)) in different bromide-based systems that could be used as lixiviants in hydrometallurgical route of metals recovery. The analysis of the corrosion products was carried out by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. All measurements showed that the addition of bromine in the electrolyte favors to great extents the dissolution process of all studied metals as compared to bromine-free electrolytes. In the investigated experimental conditions, the highest dissolution rates of the metals were obtained in acidic KBr solution containing 0.01 mol/L bromine and they decreased in the following order: Zn >> Sn > Pb > Fe > Cu. The XRD and XPS chemical assessment allowed the identification of the dissolution products formed on the metallic surfaces after exposure to the electrolytes. They consisted mainly of oxides in the case of Cu, Zn, Sn and Fe, while the presence of PbBr₂ was also noticed on the lead surface. Based on the results of EIS and surface investigations, several models explaining the corrosion behavior of the metals were proposed and discussed. The obtained results demonstrate that all studied metals could be successfully leached using brominated solutions, providing a viable alternative for the selective and efficient recovery of the base metals from WPCBs through a multi-step hydrometallurgical processing route. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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13 pages, 4098 KiB

Open AccessArticle

by Julian Kubisztal, Bożena Łosiewicz, Paulina Dybal, Violetta Kozik and Andrzej Bak

Materials 2020, 13(11), 2563; https://doi.org/10.3390/ma13112563 - 4 Jun 2020

Cited by 6 | Viewed by 2151

Abstract

Sulfolane-induced corrosion can lead to severe impairment in industrial systems. Therefore, determination of solvent corrosivity is valid. Under standard conditions, pure sulfolane is considered to be thermally stable and chemically inert, hence non-aggressive towards carbon/stainless steel. Unfortunately, the sulfolane-evoked corrosion of the industrial [...] Read more.

Sulfolane-induced corrosion can lead to severe impairment in industrial systems. Therefore, determination of solvent corrosivity is valid. Under standard conditions, pure sulfolane is considered to be thermally stable and chemically inert, hence non-aggressive towards carbon/stainless steel. Unfortunately, the sulfolane-evoked corrosion of the industrial installations is observed for sulfolane-based systems polluted by small quantities of oxygen, water and some oxidizing agents. Moreover, sulfolane decomposition with formation of corrosive (by-)products can be escalated by some process parameters, e.g., temperature. The main objective of this study was to determine the corrosion resistance of AISI 1010 steel immersed in sulfolane at temperatures ranging from 25 to 230 °C. Evaluation of the corrosion damage was carried out using electrochemical techniques and scanning probe/electron microscopy, respectively. The general corrosion tendency, corrosion rate and surface corrosion degree were taken into account as well. It was noticed that the corrosion rate linearly increases with the enhancement of sulfolane temperature. Moreover, the interfacial reaction of steel with sulfolane resulted in the formation of corrosion product layer, which is a physical barrier between the corrosive environment and steel improving corrosion resistance of the latter. In fact, the increment of the sulfolane temperature caused a gradual breakdown of the protective layer and the increase in the corrosion degree of the investigated steel. Finally, it was found that the corrosion degree doubles approximately every 42 °C. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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11 pages, 6745 KiB

Open AccessArticle

The Oxidation Resistance of Nb-Si-Based Alloys at Intermediate and High Temperatures

by Jianyong Yang, Guanqun Zhuo, Kaiyong Jiang, Xinghan Zhu and Linfen Su

Materials 2020, 13(5), 1229; https://doi.org/10.3390/ma13051229 - 9 Mar 2020

Cited by 9 | Viewed by 2206

Abstract

The oxidation behavior of three Nb-Si-based alloys were evaluated at intermediate (800 °C) and high (1250 °C) temperatures for 100 h in air. At 800 °C, the Nb-24Ti-15Si-13Cr-2Al-2Hf (at. %) alloy suffered from catastrophic pest oxidation. This pest phenomenon was suppressed by the [...] Read more.

The oxidation behavior of three Nb-Si-based alloys were evaluated at intermediate (800 °C) and high (1250 °C) temperatures for 100 h in air. At 800 °C, the Nb-24Ti-15Si-13Cr-2Al-2Hf (at. %) alloy suffered from catastrophic pest oxidation. This pest phenomenon was suppressed by the addition of Sn. However, Ta addition protected the Nb-Si-based alloys from pest oxidation for a short time. At 1250 °C, Sn could enhance the oxidation resistance of Nb-Si-based alloys due to the formation of a Sn-rich layer. In addition, the oxidation mechanisms of Nb-Si-based alloys at intermediate and high temperatures were discussed. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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8 pages, 4964 KiB

Open AccessArticle

The Distribution of Li Ions in the Oxide Film Formed on Zircaloy-4 Corroded in Lithiated Water at 633 K

by Shijing Xie, Bangxin Zhou, Xue Liang, Qiang Li, Wenqing Liu, Meiyi Yao and Jinlong Zhang

Materials 2020, 13(4), 873; https://doi.org/10.3390/ma13040873 - 15 Feb 2020

Cited by 5 | Viewed by 1893

Abstract

Transmission electron microscopy (TEM), second ion mass spectrum (SIMS) and atom probe tomography (APT) techniques are used to study the Li ion distribution in the oxide formed on the rolling surface (S_N) of Zircaloy-4 corroded in lithiated water with 0.01 M [...] Read more.

Transmission electron microscopy (TEM), second ion mass spectrum (SIMS) and atom probe tomography (APT) techniques are used to study the Li ion distribution in the oxide formed on the rolling surface (S_N) of Zircaloy-4 corroded in lithiated water with 0.01 M LiOH at 633 K/18.6 MPa. The results showed that the Li ions segregated in the grain boundaries and subgrain boundaries in the oxide film, but nearly no Li ions were found in the oxide around the interface between the oxide and matrix. Finally, we discussed the mechanism of the LiOH influence on the corrosion resistance of Zircaloy-4. Full article

(This article belongs to the Special Issue Corrosion and Corrosion Inhibition of Metals and Their Alloys)

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