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Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Formage, Forming, Laminage, Rolling, Traitements de surface, Surface treatment, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Application, Aplicación, Anwendung, Corrosion, Corrosión, Korrosion, Formage, Forming, Conformado, Umformen, Impédance, Impedance, Impedancia, Laminage à froid, Cold rolling, Laminado en frío, Kaltwalzen, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Microscopie force atomique, Atomic force microscopy, Microscopía fuerza atómica, Oxyde de fer, Iron oxide, Hierro óxido, Eisenoxid, Passivation, Pasivación, Passivierung, Polarisation anodique, Anodic polarization, Polarización anódica, Anodische Polarisation, Polymère, Polymer, Polímero, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Pyrrole polymère, Pyrrole polymer, Pirrol polímero, Revêtement composite, Composite coating, Revestimiento compuesto, Synthèse, Synthesis, Síntesis, Tôle laminée à froid, Cold rolled sheet, Chapa laminada en frío, Kaltgewalztes Blech, anodic polarization, composite coatings, conducting atomic force microscopy, conducting polymers, corrosion, electrochemical impedance spectroscopy, micaceous iron oxide, passivation, and polypyrrole

Novel hybrid composite pigments consisting of micaceous iron oxide (MIOX) and polypyrrole (PPy) were synthesized using a chemical oxidative polymerization method and water as a reaction medium. Three different particle sizes (5, 10, and 30 μm) of MIOX, namely. MIOX5, MIOX10, and MIOX30, were used for the synthesis of MIOX/PPy composite pigments. The synthesized hybrid composite pigment was characterized by scanning electron microscopy (SEM) for morphology, energy-dispersive spectroscopy (EDS) for elemental analysis, four-point probe conductivity, and conductive-atomic force microscopy (C-AFM) for conductivity studies. Density tests were also performed for the adhesion between MIOX and PPy. MIOX30/ PPy composite pigment-based coatings were formulated at 15, 25, and 35% pigment volume concentration (PVC) on cold-rolled steel and were exposed to salt spray test conditions according to ASTM B117. Corrosion performance was analyzed by electrochemical impedance spectroscopy (EIS) and anodic polarization. Equivalent circuit modeling of the EIS data was performed for the understanding of the corrosion processes on the coated substrate. A smaller drop in impedance was observed for MIOX30/PPy composite pigment-based coating at 100 days of salt spray exposure than MIOX30 pigment coating for the same duration of exposure.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion, Corrosión, Korrosion, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, Système intelligent, Intelligent system, Sistema inteligente, coatings, corrosion, multifunctional, nanoscale materials, self-healing, and smart materials

Development of materials possessing the ability to recover their main function(s) in response to destructive impacts is, today, one of most rapidly growing fields in material science. In particular, protective organic coatings with the features to heal or restore their protective function autonomously are of great interest infighting surface deterioration processes like corrosion, biofouling, and other affecting metallic structures. Embedding of micro- and nanocontainers in protective coatings is a frequently used technique nowadays to provide them one or several feedback-active functionalities. Depending on the container's morphology and active agent(s) filled, coatings with specifically aimed self-recovering functionalities (anticorrosive, water-repelling, antifouling, etc.) or multifunctional coatings can be created. In the present paper, different types of containers for self-recovering functional coatings synthesized by use of mesoporous nano- and microparticles or on the emulsion basis are presented. L-b-L polyelectrolyte deposition, interfacial polymerization, surface precipitation, Pickering emulsions, and in situ emulsion polymerization were utilized for the preparation of nano- or micro-scaled containers. Morphology of containers, efficiency of encapsulation, and kinetics of active agents release were investigated using modem techniques such as transmission mode in the scanning electron microscopy (T-SEM), cryo scanning electron microscopy (Cryo-SEM), etc. Incorporation of containers in the coating matrix was followed by the experimental modeling of external impacts, leading to simultaneous container damage. Subsequent release of the active agent at the affected site caused the active feedback of the coating and self-recovery of its specific protective function. The advantages of novel container-based protective coatings as compared to conventional ones are illustrated by corrosion tests results according to ASTM Standard B117.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Nettoyage. Dégraissage. Décapage, Cleaning. Degreasing. Pickling, Corrosion, Action des agents de corrosion, Corrosion environments, Adhérence, Adhesion, Adherencia, Adhaesion, Alliage base aluminium, Aluminium base alloys, Corrosion, Corrosión, Korrosion, Dépôt conversion, Conversion coating, Depósito conversión, Konversionsbeschichten, Nettoyage surface, Surface cleaning, Limpieza superficie, Oberflaechenreinigen, Préparation surface, Surface preparation, Preparación superficie, Oberflaechenvorbereitung, Prétraitement, Pretreatment, Pretratamiento, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, AA2024-T3, acetoacetate, adhesion, blister test, cleaning, conversion coating, surface preparation, and x-ray photoelectron spectroscopy

The blister test was used to assess the effect of various pretreatments, including chromate conversion coatings, non-chromium process conversion coatings, and trivalent chromium process coatings, on the adhesion strength of acetoacetate coatings to aluminum alloy (AA)2024-T3 (UNS A92024). The effects of cleaning and desmutting prior to conversion coating and improper water rinse temperature after cleaning were also addressed. The results revealed that when properly applied, pretreatments improved the adhesion strength of acetoacetate primer on AA2024-T3. In addition, cleaning and desmutting improved adhesion for all conversion coatings, except for chromate conversion coatings, and the level of adhesion depends on the particular conversion coating used. Process control was found to be of great significance for the performance of acetoacetate coating systems applied on AA2024-T3, as a low rinse water temperature after cleaning resulted in coating blistering.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Acier ferritique, Ferritic steel, Acero ferrítico, Ferritischer Stahl, Corrosion, Corrosión, Korrosion, Inhibiteur corrosion, Corrosion inhibitor, Inhibidor corrosión, Korrosionsinhibitor, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Silice, Silica, Sílice, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, hollow mesoporous silica, hybrid coating, inhibitor, and nanocontainer

The present work describes the development of an active corrosion protection system consisting of organic-inorganic hybrid sol-gel coating impregnated with inhibitor-loaded nanocontainers. Hollow mesoporous silica spheres were synthesized using the sol-hydrothermal method and were then used as nanocontainers to load the corrosion inhibitor molecule, 2-mercaptobenzothiazole. A silane-zirconia-based hybrid coating containing hollow mesoporous silica nanocontainers were applied on modified 9Cr-1Mo ferritic steels. The loading and releasing properties of hollow mesoporous silica nanocontainers were studied using UV-visible spectroscopy. The corrosion resistance and active corrosion protection efficiency of hybrid silane-zirconia coatings with and without the addition of inhibitor-loaded hollow mesoporous silica (SiO2) nanocontainers were studied using electrochemical impedance spectroscopy and scanning electron microscopy. The anticorrosive property of the hybrid coating impregnated with inhibitor-loaded nanocontainers was found enhanced in comparison with both the hybrid coating and hybrid coating mixed with empty nanocontainers. This enhancement in corrosion resistance was due to controlled and sustained release of the corrosion inhibitor from nanocontainers embedded in the hybrid coating.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Alliage base nickel, Nickel base alloys, Application, Aplicación, Anwendung, Chrome alliage, Chromium alloy, Cromo aleación, Chromlegierung, Corrosion eau, Water corrosion, Corrosión agua, Wasserkorrosion, Corrosion intergranulaire, Intergranular corrosion, Corrosión intergranular, Interkristalline Korrosion, Ecrouissage, Work hardening, Endurecimiento en frío, Energie, Energy, Energía, Fissuration corrosion sous tension, Stress corrosion cracking, Fisuración por tensocorrosión, Spannungsrissbildung, Fissuration intergranulaire, Intergranular cracking, Agrietamiento intergranular, Interkristalline Rissbildung, Générateur vapeur, Steam generator, Generador vapor, Réacteur eau pressurisée, Pressurized water reactor, Reactor agua a presión, Druckwasserreaktor, Réacteur nucléaire, Nuclear reactor, Reactor nuclear, Kernreaktor, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vapeur eau, Water vapor, Vapor agua, Wasserdampf, Alloy 600, Alloy 800, Alloy TT690, cold work, pressurized water reactor, stainless steel, steam generator, and stress corrosion cracking

The purpose of this research was to compare the stress corrosion cracking (SCC) resistance of materials used at the present time for steam generator (SG) tubing in pressurized water reactor (PWR) primary water. Our results in PWR primary water for 20% cold-worked (CW) Alloy 800 (UNS N08800) are compared with already published data for SCC growth from 20%CW Alloy thermally treated (TT)690 (UNS N06690), 20%CW Alloy mill-annealed (MA)600 (UNS N06600), and 20%CW austenitic stainless steels. The second purpose was to examine the dependence of SCC growth on nickel and chromium in PWR primary water; the objective was to obtain the basic knowledge to understand SCC behavior of SG tubing materials. The third objective was to understand whether accelerated testing at higher temperatures is appropriate for predicting SCC initiation and growth at lower temperatures. For these objectives, SCC growth was measured in PWR primary water at 290, 320, 330, 340, and 360°C under static load conditions. Tests were performed using 0.5T compact tension-type specimens using laboratory-melted 20%CW Alloy 800 (UNS N08800, CW800NG) and 20%CW X%Ni-16%CW-Fe alloys in the range of nickel concentration between 16% to 60%. Four important patterns were observed. First, excellent SCC growth resistance was observed for 20%CW 800NG at 320°C and 340°C; second, significant effect of nickel on IGSCC resistance was observed at 340°C and 360°C. The rate of IGSCC growth decreases with increasing nickel concentration in the range of nickel concentration between 10% to 25% nickel; then, the rate of IGSCC increases with increasing nickel concentration in the range of nickel content between 50% to 76%. This trend is quite similar to the results reported by Coriou and Staehle tested in dearated pure water at 350°C. No significant dependence of IGSCC in pure water at 320°C and 290°C was observed. The change in SCC growth dependence on nickel concentration suggested that the main rate-limiting processes on IGSCC growth seems to change between 320°C to 340°C. Third, significant beneficial effects of chromium in alloys were observed at 320°C. However, no beneficial effect of chromium addition in alloys was observed at 360°C. Finally, peak temperatures in growth rate of IGSCC were observed in almost all test materials except for 20%CW Alloy 600. The most important engineering meaning of the complicated temperature dependence with peak is that the mechanism of IGSCC growth at higher temperature is different from that at operating temperature. Furthermore, the order of SCC resistance at higher temperature is not the same at operating temperature. This means that we should pay careful attention to assess SCC from accelerated testing at higher temperatures.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Composition chimique, Chemical composition, Composición química, Chemische Zusammensetzung, Corrosion, Corrosión, Korrosion, Diffusion, Difusión, Inclusion non métallique, Non metallic inclusion, Inclusión no metálica, Nichtmetallischer Einschluss, Microstructure, Microestructura, Mikrogefuege, Plasma, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, corrosion resistance, inclusion, plasma treatments, steel, and surface microstructure

The influence of surface microstructure and chemical composition on the corrosion behavior of AISI 1045 (UNS G10450) plain steel modified by plasma-assisted diffusion of nitrogen and oxygen was investigated. A detailed surface characterization was performed before and after cyclic potentiodynamic polarization and salt spray tests, using scanning electron microscopy at low and high resolutions, energy-dispersive x-ray spectroscopy, x-ray diffraction, and glow discharge optical emission spectroscopy. The corrosion resistance as determined by cyclic potentiodynamic polarization was found to depend more strongly on the morphology and composition of the outermost oxynitride layer than on its thickness. For post-oxidation times below and above 90 min, the oxynitride layer presented defects that can act as pathways for corrosive species. The degradation of the corrosion resistance for longer processing times is through cracking of granules, which were previously formed at shorter times owing to the hydrogen accumulation at the oxide-nitride interface. The salt spray tests revealed a main dependence on the manganese sulfide (MnS) inclusions content in the base material.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Frottement. Usure, Contact of materials. Friction. Wear, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Alliage résistant corrosion, Corrosion resistant alloy, Aleacion corrosiorresistente, Korrosionsfeste Legierung, Corrosion avec érosion, Erosion corrosion, Corrosión con erosión, Erosionskorrosion, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Kohlendioxid, Ecrouissage, Work hardening, Endurecimiento en frío, Erosion, Erosión, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Usure, Wear, Desgaste, Verschleiss, Vitesse corrosion, Corrosion rate, Velocidad corrosión, Korrosionsgeschwindigkeit, CO2 corrosion, cold-working, corrosion-resistant alloys, erosion corrosion, impingement cell, stainless steel, and synergy

The erosion-corrosion behavior of two corrosion-resistant alloys (UNS S42000 and UNS N08028) has been assessed under gaseous-liquid-solid impingement conditions. Erosion-corrosion impingement tests were conducted at three different impact angles and at three different impact velocities up to 60 m/s, and furthermore, pure erosion and pure corrosion impingement tests were run for UNS S42000, and carbon dioxide (CO2) at a pressure of 1,500 kPa was used as the gas phase. The sand content, with grain size below 150 μm, was 2.7 g/L brine. Artificial brine with a sodium chloride (NaCl) content of 2.7% was used as liquid phase. The damaged surfaces of samples exposed to the high-velocity multiphase flow were investigated using scanning electron microscopy (SEM) and an optical device for 3D surface measurements to assess the depth of attack. Electrochemical investigations according to ASTM G61 were performed to determine electrochemical behavior of tested materials including critical pitting potentials (Epit) and repassivation potentials (Erepass). Furthermore, the surfaces near regions of the samples tested were investigated using applying atomic force microscopy (AFM), magnetic force microscopy (MFM). and nano-indentation measurements. From the analysis, variation of velocity shows the greatest effect on the degradation rate of both materials. In this paper the erosion-corrosion behavior and rates of two stainless steels are presented. The effects of their chemical composition and mechanical properties are discussed.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion atmosphérique, Atmospheric corrosion, Corrosión atmosférica, Atmosphaerische Korrosion, Corrosion filiforme, Filiform corrosion, Corrosión filiforme, Fadenkorrosion, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Spectrométrie Raman, Raman spectrometry, Espectrometría Raman, Raman spectroscopy, atmospheric corrosion, filiform corrosion, organic coating, and steel

The atmospheric corrosion of coated steel samples with artificial defects was characterized to determine the environmental variables that are important in the corrosion process. Coated steel samples were exposed to different climates in Hawaii, Florida, and Ohio. The iron oxides formed under the coating were identified with Raman spectroscopy, which allowed the corrosion mechanisms to be deduced. Those mechanisms were influenced by the time of wetness (TOW) and the deposition rate of chloride and sulfur that were measured at the different sites. Two corrosion morphologies were observed: bead-like corrosion was formed in the defect vicinity and filiform corrosion (FFC) was initiated from the bead-like corrosion. Bead-like corrosion was influenced by the TOW and the salt deposition, whereas FFC grew in the humid environment, but its mechanism was independent of the salt deposition. At almost all of the sites tested, chloride was the only salt that participated in the corrosion process.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Acier galvanisé, Galvanized steel, Acero galvanizado, Alliage base aluminium, Aluminium base alloys, Alliage base zinc, Zinc base alloys, Aluminium alliage, Aluminium alloy, Aluminio aleación, Aluminiumlegierung, Corrosion, Corrosión, Korrosion, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, magnesium, metal coatings, scanning electron microscopy, x-ray diffraction, and zinc

In this work the hot-dip galvanizing coating ZnAl2Mg2 was tested against the reference material ZnAlO.2 in various standardized cyclic corrosion tests with alternating climates. Those tests were the VDA 621-415 test and the VDA 233-102 test, two tests with alternating humidity and temperatures as well as salt spray phases, developed in the automotive industry. Additionally, the materials were tested in a condensation climate with a constant humidity test and a condensation climate with alternating humidity and air temperature tests. As a reference, a standardized salt spray test was performed. The corrosion products on the alloys were analyzed using x-ray diffraction (XRD). Additionally, the corrosion behavior of the samples was investigated by studying cross-sectional cuts with scanning electron microscopy (SEM). It was found that the spread in corrosion performance between the ZnAl2Mg2 coating and the conventional coating decreased in the alternating climate tests by a factor of about 2. This decrease was attributed to the reduction of the chloride exposure time and the reduced time of wetness for these tests. These factors impeded the formation of protective corrosion products, because the buffering of magnesium ions was inhibited.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion atmosphérique, Atmospheric corrosion, Corrosión atmosférica, Atmosphaerische Korrosion, Corrosion eau mer, Sea water corrosion, Corrosión agua mar, Meerwasserkorrosion, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Impédance, Impedance, Impedancia, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Perte masse, Mass loss, Pérdida masa, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Prétraitement, Pretreatment, Pretratamiento, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, atmospheric corrosion, electrochemical impedance spectroscopy, organic coatings, scanning electron microscopy, weight loss, and x-ray diffraction

In this work, five coating systems combining different surface treatments were applied to steel samples and compared with a model system used in civil structures. The corrosion behavior under an aggressive marine environment was evaluated for two years of exposure. An excellent anticorrosive performance was demonstrated for a phosphate conversion coating-based surface treatment developed by our research group. The anticorrosive performance of this new protective system is comparable to those provided by abrasive blasting, which entails environmental and economic advantages. These conclusions were supported by means of electrochemical impedance spectroscopy (EIS) and surface characterization (x-ray diffraction [XRD]. Fourier transform infrared spectroscopy [FTIR], scanning electron microscopy [SEM], and energy-dispersive x-ray spectroscopy [EDX]).

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Propriété mécanique, Mechanical properties, Propiedad mecánica, Acier haute résistance, High strength steel, Acero alta resistencia, Hochfester Stahl, Anode sacrificielle, Sacrificial anode, Anodo sacrificial, Opferanode, Corrosion, Corrosión, Korrosion, Fissuration corrosion sous tension, Stress corrosion cracking, Fisuración por tensocorrosión, Spannungsrissbildung, Fragilisation hydrogène, Hydrogen embrittlement, Fragilización hidrógeno, Wasserstoffversproedung, Hydrogène, Hydrogen, Hidrógeno, Wasserstoff, Protection cathodique, Cathodic protection, Protección catódica, Kathodischer Schutz, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Rupture, Ruptura, Bruch, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, Zink, cathodic protection, environmentally assisted cracking, fracture, high-strength steel, hydrogen embrittlement, sacrificial anodes, and zinc primers

Scribed panel testing under cyclic salt fog conditions indicates that Zn-rich coatings reduce the corrosion damage observed in armor steel as compared to traditional coatings. Constant extension rate and rising step load testing on armor steel were conducted to evaluate the effect of the Zn-rich coating on environmentally assisted crack (EAC) initiation and propagation in a marine environment. It was found that the presence of the Zn-rich coating did moderately degrade the resistance to crack initiation compared to uncoated steel during immersion in artificial seawater. It was also found that the presence of the Zn-rich coating approximately doubled the crack propagation rates compared to uncoated steel in seawater immersion. Adding a chemical agent resistant coating (CARC) topcoat to the Zn-rich coating improved the resistance to crack initiation in the constant extension rate tests, but had no effect on the crack propagation rates. Intergranular and quasi-cleavage fracture modes were noted for the environment-affected test specimens. Seawater exposures followed by a drying time had no residual effect on crack initiation behavior in air as evaluated by the constant extension rate test. In the presence of a precrack, seawater exposure can serve to initiate cracking, and subsequent arrest during the drying period will depend on the mechanical driving force (i.e., applied stress intensity). The subcritical crack growth rates for Zn-coated material during the drying period is slower than under full immersion conditions, and is similar to, or less than, values obtained for the uncoated condition.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Corrosion, Corrosión, Korrosion, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Délaminage, Delamination, Delaminación, Schichtabloesung, Epoxyde résine, Epoxy resin, Epóxido resina, Epoxidharz, Impédance, Impedance, Impedancia, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, aluminum, cathodic delamination, electrochemical impedance spectroscopy, epoxy, and x-ray diffraction

An epoxy/polyamide coating was reinforced with various loadings of aluminum particles. The coatings were applied on steel panels. The corrosion resistance, cathodic delamination, and surface morphology of the coatings were studied by electrochemical impedance spectroscopy (EIS) (3.5 wt% sodium chloride [NaCl]), a sacrificial Mg anode, optical microscopy, and x-ray diffraction (XRD) techniques, respectively. Results showed that aluminum particles improved corrosion resistance of the epoxy coating significantly. The rate of cathodic delamination of the coating was reduced in the presence of the particles noticeably. The corrosion protection mechanism of the coating was changed using low and high loadings of the particles. The aluminum particles showed active/passive behaviors against the corrosive electrolyte depending on exposure times. The lamellar aluminum particles improved barrier properties of the coating and behaved as a sacrificial pigment at long immersion times. This pigment reduced cathodic activity of the substrate by an aluminum oxide layer formation.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Microstructure, Microestructura, Mikrogefuege, Alliage base nickel, Nickel base alloys, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Foret (outil), Drill, Broca (herramienta), Bohrer, Inclusion non métallique, Non metallic inclusion, Inclusión no metálica, Nichtmetallischer Einschluss, Outil coupe, Cutting tool, Herramienta corte, Zerspanungswerkzeug, Protection, Protección, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tube, Tubo, Rohr, Usinage, Machining, Mecanizado, Zerspanen, Vitesse corrosion, Corrosion rate, Velocidad corrosión, Korrosionsgeschwindigkeit, corrosion rate, corrosion resistance, inclusions, organic coating, and pitting

G105 (API SPEC 5D group 3)-coated drill pipes suffer from washout after drilling for 70.000 m to 80,000 m. The microstructure, micromorphology, and corrosion products near the washout were analyzed by metallurgical microscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Electroless plating Ni-P as drill pipe protection in freshwater mud was studied. Results showed the metallographic microstructure of the material was typical tempered sorbite. No fatigue crack was observed. Drill-pipe washout was caused mainly by the inclusion of manganese sulfide (MnS) in steel because of the excess S and by damaged coating, both of which induced pit nucleation and promoted the pitting corrosion process. Electroless plating was cystiform in structure on the surface, and phosphorus content was 13.23%, which was high phosphorus and corrosion-resistant plating. Maximum corrosion rate of electroless plating was a quarter of the minimum of the corrosion rate of G105. Organic coating was damaged by enhanced abrasion after 10 h, and electroless plating did not change basically after 50 h. Organic coating bubbled after 10 h under low velocity because of high-temperature corrosion, but electroless plating had no change.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Impédance, Impedance, Impedancia, Procédé sol gel, Sol gel process, Procedimiento sol gel, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, aluminum, impedance, organic coatings, pitting corrosion, and potentiodynamic polarization

The effect of hydrotalcite (HT) on the protection of aluminum alloy by sol-gel films was investigated by electrochemical impedance spectroscopy (EIS) and electrochemical noise measurements (ENM). Samples of 1, 5, and 10 wt% of HT were tested. Improved performance was observed and the main action of HT was explained by its buffering capacity, which reduces locally aggressive conditions and maintains the stability of the films. A comparison between EIS and ENM results showed differences in the response of the coatings that may have come from pitting activation triggered by EIS measurements at the beginning of immersion, which, in turn, may lead to premature failure and erroneous coating evaluation.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier non allié, Carbon steel, Acero no aliado, Unlegierter Stahl, Corrosion eau mer, Sea water corrosion, Corrosión agua mar, Meerwasserkorrosion, Impédance, Impedance, Impedancia, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement composite, Composite coating, Revestimiento compuesto, carbon steel, coatings, electrochemical impedance spectroscopy, and seawater

The anticorrosion behavior of the superhydrophobic composite coating in sterilized seawater is investigated using x-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), and water contact angle measurement. The results show that when immersed into sterilized seawater, slight surface damage has been observed, leading to the decrease of water contact angle. The electrochemical measurements, however, reveal good protection of steel substrate from the composite coating. From the viewpoint of anticorrosion ability, the composite coating maintains well after 168 h immersion in seawater and can provide carbon steel with good protection from seawater attack. The corrosion mechanism of the coated samples immersed in seawater is proposed through the schematic diagram. The corrosion medium reaches the carbon steel substrate through the channel forming in the composite coating. With the increase of the immersion time, the corrosion pits develop into the carbon steel.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Formage, Forming, Laminage, Rolling, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base nickel, Nickel base alloys, Carbure, Carbides, Carburo, Carbid, Corrosion eau, Water corrosion, Corrosión agua, Wasserkorrosion, Ecrouissage, Work hardening, Endurecimiento en frío, Fissuration corrosion sous tension, Stress corrosion cracking, Fisuración por tensocorrosión, Spannungsrissbildung, Formage, Forming, Conformado, Umformen, Joint grain, Grain boundary, Limite grano, Korngrenze, Laminage à froid, Cold rolling, Laminado en frío, Kaltwalzen, Microstructure, Microestructura, Mikrogefuege, Précipitation, Precipitation, Precipitación, Ausscheidung, Réacteur eau pressurisée, Pressurized water reactor, Reactor agua a presión, Druckwasserreaktor, Réacteur nucléaire, Nuclear reactor, Reactor nuclear, Kernreaktor, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tôle laminée à froid, Cold rolled sheet, Chapa laminada en frío, Kaltgewalztes Blech, Alloy 690, carbide precipitation, cold work, grain boundaries, microstructure, pressurized water reactor primary water, and stress corrosion cracking

Grain boundary microstructures and microchemistries are examined in cold-rolled Alloy 690 (UNS NO6690) materials and comparisons are made to intergranular stress corrosion cracking (IGSCC) behavior in pressurized water reactor (PWR) primary water. Chromium carbide precipitation is found to be a key aspect for materials in both the mill-annealed and thermally treated conditions. Cold rolling to high levels of reduction was discovered to produce small IG voids and cracked carbides in alloys with a high density of grain boundary carbides. The degree of permanent grain boundary damage from cold rolling was found to depend directly on the initial IG carbide distribution. For the same degree of cold rolling, alloys with few IG precipitates exhibited much less permanent damage. Although this difference in grain boundary damage appears to correlate with measured SCC growth rates, crack tip examinations reveal that cracked carbides appeared to blunt propagation of IGSCC cracks in many cases. Preliminary results suggest that the localized grain boundary strains and stresses produced during cold rolling promote IGSCC susceptibility and not the cracked carbides and voids.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Frottement. Usure, Contact of materials. Friction. Wear, Propriété mécanique, Mechanical properties, Propiedad mecánica, Adhérence, Adhesion, Adherencia, Adhaesion, Alliage base aluminium, Aluminium base alloys, Corrosion, Corrosión, Korrosion, Morphologie, Morphology, Morfología, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, AA6061-T6 alloy, adhesion, corrosion, surface treatment, and wear

The surface morphology, wear resistance, and adhesiveness of aluminum alloy (AA)6061-T6 (UNS A96061) treated in a hexafluorozirconic acid-based solution were studied. The treated alloys had higher resistance to moisture-induced corrosion than the untreated alloys, which was indicated by the smaller increments in roughness of the treated alloys with prolonged exposure to 99.5% relative humidity. The treated alloys did not show a better scratch-induced wear resistance than the untreated alloys. However, the surface treatment resulted in a more difficult removal of a high molecular weight epoxy topcoat from the treated alloy surfaces during scratching in air and water with an atomic force microscopy (AFM) tip because of the enhanced adhesion strength of the topcoats.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Contamination, Contaminación, Corrosion, Corrosión, Korrosion, Grosseur grain, Grain size, Grosor grano, Korngroesse, Microstructure, Microestructura, Mikrogefuege, Traitement mécanique, Mechanical treatment, Tratamiento mecánico, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, corrosion, grain size, magnesium, polarization, and surface mechanical attrition treatment

Surface mechanical attrition treatment (SMAT) is a mechanical peening process used to generate ultrafine grain surfaces on a metal. SMAT was carried out on pure magnesium using different attrition media (zirconia [ZiO2], alumina [Al2O3], and steel balls) to observe the effect on microstructure, surface residual stress, surface composition, and corrosion. Surface contamination from SMAT was characterized using glow discharge optical emission spectroscopy (GDOES). The SMAT process produced a refined grain structure on the surface of Mg but resulted in a region of elemental contamination extending ∼10 μm into the substrate, regardless of the media used. Consequently, SMAT-treated surfaces showed an increased corrosion rate compared to untreated Mg, primarily through increased cathodic kinetics. This study highlights the issue of contamination resulting from the SMAT process, which is a penalty that accompanies the significant grain refinement of the surface produced by SMAT. This must be considered if attempting to exploit grain refinement for improving corrosion resistance.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base nickel, Nickel base alloys, Corrosion avec érosion, Erosion corrosion, Corrosión con erosión, Erosionskorrosion, Diagramme polarisation, Polarization diagram, Diagrama polarización, Polarisationsdiagramm, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Erosion, Erosión, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tungstène alliage, Tungsten alloy, Wolframio aleación, Wolframlegierung, erosion-corrosion, nickel, and polarization curve

The amorphous Ni-W-P coating with 4.8 wt% W and 9.8 wt% P was electrodeposited from the electrolytic bath. Using a slurry pot erosion tester, the erosion-corrosion behavior of this Ni-W-P coating was investigated in 3.5 wt% sodium chloride (NaCl) slurry with 3 wt% sand particles (80 μm to 120 μm) at the impact velocities of 3.14, 5.23, and 8.37 m s―1, respectively. After erosion-corrosion in the saline-sand slurry, the hardness of Ni-W-P coating was increased from HV616 to HV722. The mechanical effect of sand particle impact causes crystallization of the coating surface and the work-hardening leads to accelerated corrosion. The microstructure was transformed from amorphous to a mixture of amorphous and multiple crystal phases. With the observation of an eroded surface of the Ni-W-P coating, the fracture of the cracking lips was aggregated by the interaction between impacts of sand particles and corrosion pitting of Cl― solution. The total mass-loss rate of amorphous Ni-W-P coating was increased obviously with the increase of impact velocity and could be evaluated with kV2.9, which was approximately 10 mg h―1 at the impact velocity of 8.37 m s―1. Compared with Ni-P coating, the enhancement of hardness and corrosion current density of Ni-W-P coating is benefit to its lower synergism rate and higher relative wear resistance.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Anodisation, Anodizing, Anodización, Elektrolytisches Oxidieren, Bioencrassement, Biofouling, Incrustación biológica, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion, Corrosión, Korrosion, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, anodization, biofouling resistance, corrosion resistance, organic coatings, superhydrophobicity, and titanium

The present study reveals the influence of different anodizing electrolytes on the superhydrophobic surface modification of titanium and the resultant corrosion and biofouling resistance. Inspired by the Lotus effect, anodization and low surface energy material coating were used to produce superhydrophobic titanium in the present work. The water contact angle measured on surface-modified titanium was found to be 150°, indicating their superhydrophobic nature. Surface roughness, morphology, phase, and composition of the oxide film were correlated with the superhydrophobic nature of the coated surfaces. Electrochemical studies showed that the superhydrophobic titanium in a nitric acid medium had appreciable increase in the corrosion resistance compared to the as-polished titanium. The antibacterial activity studies showed a one to two order decrease in bacterial attachment on superhydrophobic titanium samples compared to polished titanium samples.