articles+ search results

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, Pression partielle, Partial pressure, Presión parcial, Partialdruck, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, A. Iron, A. Organic coatings, A. Steel, and C. Atmospheric corrosion

An in-situ time-lapse optical microscopy study, using a novel dual-compartment cell is used to gain mechanistic understanding of filiform corrosion (FFC) affecting an organic-coated iron surface. The apparatus allows independent control of environments surrounding the filament head and tail regions. When oxygen-containing environments surround the filament head, an anterior cathodic arc is formed, constraining the filament head electrolyte. When oxygen is removed from the vicinity of the head, FFC propagation rates remain unchanged, although the constraining arc is not present. Maximum propagation is observed when oxygen is available for transport through the filament tail to the rear of the head.

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, Adhérence, Adhesion, Adherencia, Adhaesion, Affinement grain, Grain refinement, Afino grano, Kornfeinen, Alumine, Alumina, Alúmina, Tonerde, Aluminure, Aluminides, Aluminuro, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion, Corrosión, Korrosion, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Grosseur grain, Grain size, Grosor grano, Korngroesse, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Oxydation, Oxidation, Oxidación, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Metal coatings, B. SEM, B. TEM, B. XRD, and C. Oxidation

To understand the effect of grain refinement on the thermally grown alumina scale adhesion to the metal substrate, two δ-Ni2Al3 coatings, one coarse-grained (~70 μm) and the other ultrafine-grained (generally below ~500 nm), were prepared. The cyclic oxidation in air at 1100 °C shows that the ultrafine-grained (UFG) coating is better oxidation resistant than the coarse-grained (CG) coating due to the formation of a more adherent alumina scale. The latter is intrinsically correlated with the fact that the aluminide grain refinement helps to increase the oxide/metal strength through a route to prevent the formation of large-sized voids at the interface.

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, Corrosion, Corrosión, Korrosion, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Désalliage, Dealloying, Desaleación, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Synthèse, Synthesis, Síntesis, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Copper, B. SEM, B. XRD, C. De-alloying, and C. Electrodeposited films

Crack-free nanoporous Cu films were synthesized by electrochemical deposition of Cu-Zn alloy films by chronoamperometry (CA) at -0.5 V(Ag/AgCl), followed by a two-step chemical dealloying process. Various nanoporous structures were successfully created with very low concentration of less-noble element (3-4 at.% Zn), by a wet-chemical process. In addition to the Zn, less noble constituent, it is believed that Cu oxide formed during the electrochemical deposition might act as less-noble constituent as well.

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, Ablation, Ablación, Corrosion haute température, High temperature corrosion, Corrosión alta temperatura, Hochtemperaturkorrosion, Céramique, Ceramic materials, Cerámica, Keramik, Haute température, High temperature, Alta temperatura, Hochtemperatur, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Morphologie, Morphology, Morfología, Mécanisme, Mechanism, Mecanismo, Oxydation, Oxidation, Oxidación, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Température, Temperature, Temperatura, Temperatur, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, B. SEM, B. XRD, C. High temperature corrosion, and C. Oxidation

A dense SiC-Si coating with average thickness of 580 μm was prepared on graphite by pack cementation. The surface morphology evolution and ablation mechanism of the coating at about 1780 °C were investigated by oxy-acetylene flame. After applying SiC-Si coating, the ablation surface temperature dropped about 300 °C. The ablation products SiO2 presented high viscosity and provided good protection in the early-to-middle stage of the ablation. The mechanical denudation gradually became severe with the ablation time increasing. Finally, the convection between the gases formed in the subsurface and the ablative gases turned out to be the primary ablation barrier.

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 piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Couche monomoléculaire, Monolayer, Capa monomolecular, Protection, Protección, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, A. Copper, A. Organic coatings, C. Neutral inhibition, and C. Pitting corrosion

The protection performance of self-assembled monolayers (SAMs) formed by 2-(Pyridin-2-yliminomethyl)-phenol (HL) on the surface of copper has been studied in situ with the scanning electrochemical microscope (SECM). The pitting dynamic processes were observed in sodium chloride solution without the presence of SAMs, but they tended to be inhibited by SAMs if the assembly time was long enough. During the scanning process, the self-assembled method decreases the interaction between the HL molecules and the SECM tip greatly.

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, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Corrosion, Corrosión, Korrosion, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Céramique, Ceramic materials, Cerámica, Keramik, Dépôt physique phase vapeur, Physical vapor deposition, Deposición física fase vapor, Physikalisches Aufdampfen, Impédance, Impedance, Impedancia, Magnétron, Magnetron, Magnetrón, Oxyde anodique, Anodic oxide, Oxido anódico, Pulvérisation irradiation, Sputtering, Pulverización irradiación, Sputtern, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Ceramic, A. Stainless steel, A. Zirconium, B. EIS, B. XRD, and C. Anodic films

ZrCN coatings with incorporated silver were deposited on 316L stainless steel by dual reactive magnetron sputtering to evaluate the silver influence on the structural properties and corrosion resistance of the films. Samples composition was assessed by electron probe microanalysis. Glow discharge optical emission spectroscopy was used to determine the distribution of silver in the films. Structural characterization was performed by X-ray diffraction and Raman spectroscopy. Corrosion resistance was evaluated by potentiodynamic test and electrochemical impedance spectroscopy. Results revealed enhanced corrosion resistance properties of the coated steel and higher coatings reactivity when incorporated with silver, showing a plausible silver release increment.

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, Acier non allié, Carbon steel, Acero no aliado, Unlegierter Stahl, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion, Corrosión, Korrosion, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Impédance, Impedance, Impedancia, 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, A. Carbon steel, A. Organic coatings, and B. EIS

Microcapsules containing isophorone diisocyanate (IPDI) were used as self-healing additives in the alkyd varnish coatings (AVCs), and their self-healing performance was evaluated in the case of artificial defects on Q235 steel surfaces, using scanning micro-reference electrode technique and Fourier-transform infrared spectroscopy. Comparison of the micromechanical properties between the water-insoluble self-healing products (polyurethanes) and AVCs indicates that the former significantly enhanced the capability of the scratched crevice to successfully endure outer stress. The electrochemical impedance spectroscopy experiments analysed the different stages in the self-healing process. This study successfully demonstrated the self-healing activity of IPDI-AVCs in protecting steel surfaces.

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, Cellulose, Celulosa, Zellulose, Corrosion, Corrosión, Korrosion, Electrode, Electrodes, Electrodo, Elektrode, Impédance, Impedance, Impedancia, Inhibiteur corrosion, Corrosion inhibitor, Inhibidor corrosión, Korrosionsinhibitor, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Polymère, Polymer, Polímero, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, A. Steel, B. EIS, B. SEM, B. Scratching electrode, and C. Polymer coatings

Polymer coatings containing cellulose nanofibers were applied to carbon steel for corrosion inhibition. The specimens were scratched with a knife-edge, and then polarization resistance was monitored in a sodium chloride solution. The polarization resistance of the scratched specimen containing nanofibers and corrosion inhibitor was higher than that of a polymer coating that contained only a corrosion inhibitor. The optimal mixing ratio of corrosion inhibitor for cellulose nanofibers was 4. Empty holes were confirmed on a cross-section of the polymer coating after the corrosion test, which showed that the nanofibers served as pathways for the release of the corrosion inhibitor.

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, Corrosión, Korrosion, Epoxyde résine, Epoxy resin, Epóxido resina, Epoxidharz, Impédance, Impedance, Impedancia, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Peinture, Paint, Pintura, Anstrich, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Transport ion, Ion transport, Transporte iónica, A. Organic coating, B. EIS, B. SEM, and C. Paint coatings

An epoxy resin coating with a sandwich structure was prepared to investigate ion transport behavior in the coating. The macro- and micro- appearance of the coating immersed in 5 wt.% KCI solutions was observed by stereo microscopy, scanning electron microscopy equipped with an energy dispersive spectrometer. The electrochemical property of the coating was characterized by electrochemical impedance spectroscopy, and change of free volume after immersion was characterized by positron annihilation lifetime spectroscopy. The results indicated that Cl― ions permeated into the coating prior to K+ ions, the free volume size and positron annihilation lifetime of the coating increased during immersion.

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, Alliage base titane, Titanium base alloys, Aluminium alliage, Aluminium alloy, Aluminio aleación, Aluminiumlegierung, Apatite hydroxylée, Hydroxyapatite, Hidroxiapatito, Biomatériau, Biomaterial, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Impédance, Impedance, Impedancia, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Oxyde anodique, Anodic oxide, Oxido anódico, Oxyde de titane, Titanium oxide, Titanio óxido, Titanoxid, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vanadium alliage, Vanadium alloy, Vanadio aleación, Vanadiumlegierung, A. Titanium alloy, B. EIS, B. SEM, C. Anodic films, and C. Electrodeposited films

In order to improve the bonding strength between hydroxyapatite (HA) coating and Ti-6Al-4V substrate, a uniform titanium oxide film was obtained by controlled anodic oxidation. After that an alkaline treatment with NaOH solution was used to make them more bioactive. Finally hydroxyapatite coating has been prepared on Ti-6Al-4V substrate through electrochemical deposition. Comparative electrochemical behaviour of untreated and surface modified Ti-6Al-4V alloy, in bio-simulated fluid solution was investigated by electrochemical techniques. SEM was used to observe the morphology of modified surfaces and the thicknesses of the oxide films prepared were evaluated on the cross-sections of the samples using SEM-FIB.

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, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Acier non allié, Carbon steel, Acero no aliado, Unlegierter Stahl, Corrosion, Corrosión, Korrosion, Impédance, Impedance, Impedancia, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Nanocomposite, Nanocompuesto, Polymère, Polymer, Polímero, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement composite, Composite coating, Revestimiento compuesto, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Silice, Silica, Sílice, Spectrométrie IR, Infrared spectrometry, Espectrometría IR, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Mild steel, B. EIS, B. IR spectroscopy, B. SEM, and C. Polymer coatings

A series of nanocomposite coatings (PBS) consisting of silane functional polybenzoxazine (PB-TMOS) and SiO2 nanoparticles were developed for corrosion protection of mild steel. The influence of silica content on corrosion resistance of PBS coatings was investigated by electrochemical measurements. The surface chemistry of nanoparticles and its effect on morphology of the PBS coating was also studied utilizing Fourier Transforms Infrared Spectroscopy, 29Si Nuclear Magnetic Resonance and Scanning Electron Microscopy analyses. The results indicate that the presence of the covalent bond between nanoparticles and PB-TMOS, greatly improves the interfacial interactions at the polymer/filler interfaces resulting in a better corrosion performance.

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, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base magnésium, Magnesium base alloys, Corrosion, Corrosión, Korrosion, Implantation ion, Ion implantation, Implantación ión, Ionenimplantation, Impédance, Impedance, Impedancia, Interface, Interfase, Grenzflaeche, Néodyme alliage, Neodymium alloy, Neodimio aleación, Neodymlegierung, Plasma, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Magnesium, B. EIS, B. Ion implantation, B. Polarization, and C. Interfaces

Plasma immersion ion implantation and deposition (PIII&D) is conducted to modify the corrosion behavior of Mg―Nd―Zn―Zr alloy. A diamond-like carbon film (DLC) with a thickness of about 200 nm is formed on the surface after acetylene PIII&D and the resulting corrosion resistance in the 0,9 wt% NaCl solution is significantly improved. The corrosion mechanism is discussed from the perspective of random defects in the DLC film.

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 biochimique, Bacterial corrosion, Corrosión bioquímica, Biologische Korrosion, Fabrication, Manufacturing, Fabricación, Fertigung, Impédance, Impedance, Impedancia, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, A. Alloy, A. Magnesium, A. Organic coatings, B. EIS, B. Polarization, and C. Microbiological corrosion

Inspired by the lotus leaf, various methods to fabricate artificial superhydrophobic surfaces have been developed. Our purpose is to create a simple, one-step and environment-friendly method to construct a superhydrophobic surface on a magnesium alloy substrate. The substrate was immersed in a solution containing ferric chloride (FeCl3·6H2O), deionized water, tetradecanoic acid (CH3(CH2)12COOH) and ethanol. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared (FT-IR) were employed to characterize the substrate surface. The obtained surface showed a micron rough structure, a high contact angle (CA) of 165° ± 2° and desirable corrosion protection and antifouling properties.

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, Barrière thermique, Thermal barrier, Barrera térmica, Corrosion, Corrosión, Korrosion, Cycle thermique, Thermal cycle, Ciclo térmico, Temperaturverlauf, Interface, Interfase, Grenzflaeche, Lanthanide, Lantánido, Monocristal, Single crystal, Einkristall, Oxydation, Oxidation, Oxidación, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Superalliage, Superalloy, Superaléación, Superlegierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Metal coatings, A. Rare earth elements, A. Superalloys, B. Thermal cycling, C. Interfaces, and C. Oxidation

NiAl and NiAlHf/Ru coatings were produced onto nickel-based single crystal superalloy to investigate the interdiffusion behaviour and cyclic oxidation resistance at 1100 °C. A ∼30 μm thick layer, mainly consisting of needle-like topologically close-packed phases (TCP) and secondary reaction zone (SRZ), was formed in the NiAl coated superalloy after annealing at 1100 °C for 100 h, whereas the precipitates of TCP and SRZ were effectively constrained in the NiAlHf/Ru coated alloy. The NiAlHf/Ru coating exhibited superior cyclic oxidation resistance as compared to the NiAl coating. The roles of Ru and Hf in affecting interdiffusion and cyclic oxidation were 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 métaux et d'alliages, Metallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base zinc, Zinc base alloys, Aluminium alliage, Aluminium alloy, Aluminio aleación, Aluminiumlegierung, Corrosion atmosphérique, Atmospheric corrosion, Corrosión atmosférica, Atmosphaerische Korrosion, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Dissolution anodique, Anodic dissolution, Disolución anódica, Dépôt immersion, Dip coating, Depósito inmersión, Tauchbeschichten, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Phase initiale, Early phase, Fase inicial, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Spectrométrie photoélectron, Photoelectron spectrometry, Espectrometría fotoelectrón, ESCA Spektrometrie, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, Zink, A. Metal coatings, A. Zinc, B. AES, B. XPS, C. Anodic dissolution, and C. Atmospheric corrosion

The onset and initial progress of atmospheric corrosion of ternary alloyed Zn-Mg-Al coatings induced by an aqueous sodium chloride environment was studied in detail by means of surface sensitive techniques. X-ray photoelectron spectroscopy and Auger electron spectroscopy. Two fundamental processes were found to be involved in the initial corrosion attack: (i) dissolution of the surface layer consisting of MgO and (ii) preferential anodic dissolution of both, binary and ternary eutectic phases constituting the coating, which led to the formation of characteristic cracks/holes and was followed by a predominant deposition of zinc corrosion products around anodic regions.

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, Alliage base aluminium, Aluminium base alloys, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Corrosion, Corrosión, Korrosion, Epoxyde résine, Epoxy resin, Epóxido resina, Epoxidharz, Impédance, Impedance, Impedancia, Inhibiteur corrosion, Corrosion inhibitor, Inhibidor corrosión, Korrosionsinhibitor, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, A. Alloy, A. Aluminium, A. Organic coatings, B. EIS, and B. SEM

This work aims at investigating the corrosion protection effectiveness of multifunctional epoxy coatings modified with pigments such as ceramic nanocontainers loaded with corrosion inhibitor, chloride and water traps, applied on AA2024-T3. Characterizations on the morphology, composition and structure of the coatings were conducted. The corrosion resistance was studied by electrochemical impedance spectroscopy, localized electrochemical impedance spectroscopy and scanning vibrating electrode technique. The mechanical behaviour of the coatings was examined through nanoindentation and nanoscratching tests. Electrochemical and nanomechanical testing results, evidenced the improvement of the corrosion protective properties and mechanical behaviour of the coatings in the presence of the various pigments.

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, Corrosion, Corrosión, Korrosion, Dissolution, Disolución, Aufloesung, Inhibiteur corrosion, Corrosion inhibitor, Inhibidor corrosión, Korrosionsinhibitor, Modélisation, Modeling, Modelización, Polymère, Polymer, Polímero, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, C. Neutral inhibition, and C. Polymer coatings

A theoretical model is proposed to explain the diversity of time profiles of the release of inhibitor to a scratch in a damaged protective coating. The model involves diffusion of an inhibitor and inhibitor release-triggering species and dissolution of inhibitor. The total mass M, of inhibitor released to a scratch was approximated with a power function of time t: Ml ~ tα. The numerical simulations showed that, through variations in the properties of either the matrix or the inhibitor, primarily dissolution rate, α could be tuned to any value in the range from 0.5 to 1.5.

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, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion, Corrosión, Korrosion, In situ, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Microstructure, Microestructura, Mikrogefuege, Oxydation, Oxidation, Oxidación, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Intermetallics, A. Metal coatings, and C. Oxidation

The development of robust high temperature oxidation resistant coatings for Nb-Si based alloy was evaluated for a Mo-Si-B coating system that was applied by a two step process. It is observed that the coating is composed of an outer layer of MoSi2 containing boride dispersoids and an inner layer of unreacted Mo. The mass gain of substrate and Mo-Si-B coating is 190.08 and 1.28 mg cm-2 after oxidation at 1250 °C in dry air for 100 h, respectively. The good oxidation resistance of the coating is attributed to the formation of a continuous borosilicate glass coverage.

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, Alumine, Alumina, Alúmina, Tonerde, Carbure de silicium, Silicon carbide, Silicio carburo, Siliciumcarbid, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion, Corrosión, Korrosion, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Oxydation, Oxidation, Oxidación, Revêtement composite, Composite coating, Revestimiento compuesto, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Class, A. Intermetallics, A. Titanium, B. EPMA, B. SEM, and C. Oxidation

A SiC-Al2O3-glass composite coating was prepared on Ti-47AI-2Cr-2Nb alloy by a slurry made from aqueous solution of potassium silicate and powders of SiC and Al2O3. The oxidation behavior of the specimens was studied at 800 °C, 900 °C and 1000 °C. The composite coating prevented the inward diffusion of oxygen from air to the coating/alloy interface, therefore, decreasing the oxidation rate of the alloy remarkably. Besides, the composite coating exhibited good thermal cyclic resistance on Ti-47AI-2Cr-2Nb alloy. The microstructure changes of the composite coating, including oxidation of the SiC inclusions and the coating/alloy interfacial reaction, were investigated.

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 aluminium, Aluminium base alloys, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion, Corrosión, Korrosion, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Oxydation, Oxidation, Oxidación, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, A. Intermetallics, A. Metal coatings, B. SEM, and C. Oxidation

To protect Cr-50Nb alloys from high-temperature oxidation, the silicide diffusion coating and Si-Al coating were produced by pack cementation. The results indicate that the two coatings have three-layer structure and the interfaces are smooth. Uncoated Cr-50Nb alloy occur catastrophic oxidation at the initial oxidation stage at 1200 °C. However, the scale spalling resistance of the two coatings are improved significantly, and Si-Al coating exhibits excellent resistance to oxidation. During cyclic oxidation in air at 1200 °C for 100 h, the weight loss of Si-Al coating is 1.39 mg/cm2 and the mass gain is 6.01 mg/cm2.