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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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Métaux et alliages frittés. Cermets, Sintered metals and alloys. Pseudo alloys. Cermets, Traitements de surface, Surface treatment, 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, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Frittage, Sintering, Sinterización, Sintern, Microstructure, Microestructura, Mikrogefuege, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, Corrosion, and Intermetallics

An erbium modified Mg17Al12 based coating was fabricated by hot press sintering on as extruded AZ61 Mg alloy. The Er modified coating was composed of Mg17Al12 and Al3Er phases. As a result of the presence of the dispersed Al3Er phase, the coating had a greater microhardness than Mg17Al12. Thermal effects of sintering at 400°C for 1 h caused no obvious deterioration in the wear resistance of the AZ61 Mg matrix. Electrochemical and wear resistance tests showed that the Er modified Mg17Al12 based coating had a lower corrosion current density and a lower friction coefficient than Mg17Al12, the AZ61 Mg matrix and a thermal diffusion coating (TDC). The superior wear resistance of the sintered coating resulted from the hard Al3Er phase. The corrosion resistance of the sintered coating was better than that of the TDC as a result of suppression of hydrogen evolution by the rare earth metal Er.

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, Corrosión, Korrosion, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Irradiation, Irradiación, Bestrahlung, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Coatings, Electroless plating, Magnesium alloy, and Ultrasonic irradiation

Ultrasonic irradiation (UI) is applied to assist the electroless plating (EP) Ni―P coating on a magnesium alloy substrate. The results show that under UI, the Ni―P coating becomes smooth, compact, has refined grains and is free of cracks and pores, leading to significant improvement in the coating corrosion resistance. The crystallinity of the coating is also improved by UI, transforming from amorphous state to mixture of amorphous and nanocrystalline one.

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, Corrosion, Action des agents de corrosion, Corrosion environments, Corrosion, Corrosión, Korrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Coating, Properties, Resistance, Spraying, and Structure

Coating technology is growing because of its important role in improving, e.g. corrosion resistance, thermal and electrical conductivities, and other properties of material in order to decrease costs and increase service life and safety. Cold spraying is the technique to produce coatings from powder feedstock by spraying solid particles on the substrate, forming the coating. Cold spraying is a relatively new spraying method, which has many advantages over other forms of thermal spraying. The advantages are dense and pure structures, high deposition efficiency, low residual stresses, minimal heat input to substrate, phase and compositional stability, and little need for masking. Furthermore, cold spraying is a cost effective and environmentally friendly alternative to, e.g. soldering, electroplating, and painting. One potential application field of cold sprayed coatings is corrosion protection due to the possibility to produce fully dense and impermeable coatings. From this aspect, this review is focused on corrosion properties of cold sprayed coatings and structural details behind these coatings.

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, Corrosion, Action des agents de corrosion, Corrosion environments, Application, Aplicación, Anwendung, Corrosion, Corrosión, Korrosion, Déchet industriel, Industrial waste, Desperdicio industrial, Industrieabfall, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Incinérateur, Incinerator, Incinerador, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement déchet, Waste treatment, Tratamiento desperdicios, Abfallbehandlung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Coating, and NiCrAIY

NiCrAIY coating was deposited on Ni based Superni 76 superalloy using cold spray process to enhance the life of superalloy. The present investigation is an attempt to evaluate comparative behaviour of hot corrosion of the bare and coated superalloy in actual industrial medical waste incinerator. The study was conducted in the secondary chamber of medical waste incinerator for 1000 h under cyclic conditions at 900°C. The life of bare and coated superalloy has been evaluated based on thickness lost due to erosion-corrosion. The cold sprayed NiCrAlY coating successfully provided protection to the superalloy against hot corrosion. Based upon thickness loss data, the corrosion rate of exposed coated specimen calculated as 35·87 mpy.

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, Corrosion, Corrosión, Korrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Oxydation, Oxidation, Oxidación, Projection HVOF, HVOF spraying, Proyeccion HVOF, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, Bond coat, Cold gas dynamic spray, and High velocity oxygen fuel

CoNiCrAlY coating for protection against oxidation at elevated temperature was prepared on the surface of the 316L by high velocity oxygen fuel (HVOF) and cold gas dynamic spray (CGDS) techniques. The phase composition, microstructure and oxidation resistance of the coating were investigated at 900°C in air. According to the results, the CGDS coating shows low oxide growth rate as a result of low porosity, oxide content and high hardness. CGDS coating provided excellent oxidation protective ability at 900°C in air, whereas HVOF coating showed high levels of visible defects, oxide content, spinel type oxide and high oxide growth rate. Electrochemical study shows that the HVOF process provided better corrosion resistance as compared to CGDS 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, 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, Corrosion, Corrosión, Korrosion, Elasticité, Elasticity, Elasticidad, Elastizitaet, Indentation, Indentación, Microstructure, Microestructura, Mikrogefuege, Module Young, Young modulus, Módulo Young, Module élasticité, Elastic modulus, Módulo elasticidad, Elastizitaetsmodul, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, MAO, Magnesium, Nanohardness, Nanoindentation, and Young's modulus

The micro arc oxidation (MAO) process is one of the most industrially accepted, prospective methods to design and develop microstruturally integrated, intrinsically generated oxide/ceramic coating over Mg alloys. Here we report, the surface engineering of AZ31 Mg alloy to form MAO coatings by silicate and phosphate based electrolytes. The microstructural examinations of the MAO coatings were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. Further, the nanoindentation studies revealed that the MAO coatings had nanohardness (H) and Young's modulus (E) values as high as about 3―7 times and 1·5―2·5 times those of the as received AZ31 Mg alloy respectively. Both H and E values gradually increased from virgin Mg substrate end to the surface coating end. Further, sealing by hot water did not affect the H and E values of the MAO coatings.

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, Adhérence, Adhesion, Adherencia, Adhaesion, Alliage base magnésium, Magnesium base alloys, Corrosion, Corrosión, Korrosion, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Microporosité, Microporosity, Microporosidad, Microporositaet, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, Simulation, Simulación, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, AZ91D, and Coatings

A notebook computer component with a complex geometry was manufactured with a die cast process (DCP), using an AZ91D alloy. Chemical conversion and organic coatings were sequentially applied to provide protection against physical and chemical damage. Air content in the component, which gives rise to microporosity, was determined with a DCP computer simulation using MAGMA software. The surface layer characteristics of the component were also investigated using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The microporosity content was higher at the end of the filling process compared with the regions that filled first. Corrosion resistance was poorer for discontinuous conversion coatings that resulted from surface microporosity. Moreover, adhesion of an organic coating was degraded at areas with higher microporosity.

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, Application, Aplicación, Anwendung, Corrosion, Corrosión, Korrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Electronique, Electronics, Electrónica, Elektronik, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Applications, Cold spray, Medical, and Plastics

Modern cold spray, first implemented 30 years ago, has since expanded rapidly in system designs and applications. While initially considered to be a method to deposit a ductile metal coating onto another metal, subsequent innovations in design and use have allowed new applications to areas as diverse as medical and electronics. This paper describes some new methods and applications that are currently being developed. Twenty-four new applications are presented, chosen to represent the diversity of actual and potential uses of cold spray technology.

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, Corrosion, Corrosión, Korrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Ni, NiCu, cold spraying, corrosion properties, and structure

Cold spraying is a promising technique for the production of dense metallic coatings. In cold spraying, coating formation is through high velocity impacts of solid particles with high kinetic energy. During impact, particles deform plastically and adhere to the substrate, gradually building-up the coating. This makes it possible to form pure and dense coating structures. These impermeable coatings are advantageous in many applications such as those where corrosion protection is required. Nickel and nickel-copper alloys have good corrosion resistance and therefore, as dense coatings, have high potential for employment as corrosion barrier layers. In this study, the structural and corrosion properties of high-pressure cold-sprayed (HPCS) Ni and NiCu coatings are characterized. NiCu alloys are known to have good corrosion resistance in sulphuric and hydrochloric acids, whereas Ni is resistant to caustic soda and alkaline salt solutions. This study also shows the effect of heat treatments on coating properties. FESEM studies of cross-sectional samples reveal structural details of the HPCS coatings while corrosion properties are evaluated with polarization measurements. The corrosion behavior of both the bulk and substrate material is determined in order to assess the real corrosion protection potential of the coatings.

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, Corrosion, Corrosión, Korrosion, Fabrication, Manufacturing, Fabricación, Fertigung, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Nanocomposite, Nanocompuesto, Nanocristal, Nanocrystal, Phase amorphe, Amorphous phase, Fase amorfa, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Fe-based nanocomposite coatings, amorphous phase, corrosion resistance, nanocrystalline, and thermal spray technologies

This review focuses on the recent development of iron (Fe)-based amorphous/nanocrystalline composite coatings, which have attracted much attention due to their attractive combination of high hardness/strength, elevated abrasive wear resistance, and enhanced corrosion resistance. Accompanying the advancements in various thermal spray technologies, industrial application fields of Fe-based amorphous/nanocrystalline composite coatings are becoming more diverse. In the main part, the typical empirical rules for the design of amorphous alloys with high glass-forming ability are generalized and discussed at first. Then various thermal spray technologies for the fabrication of Fe-based amorphous/nanocrystalline composite coatings, such as high velocity oxygen/air spray (HVOF/HVAF), air plasma spray (APS), low-pressure plasma spray (LPPS), high-energy plasma spray (HPS), and high velocity arc spray (HVAS) processes, are introduced. The microstructures, hardness, wear resistance, and corrosion resistance of Fe-based amorphous/nanocrystalline composite coatings formed using these thermal spray technologies are reviewed and compared. Finally, the existing challenges and future prospects are proposed.

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, Corrosion, Protection contre la corrosion, Corrosion prevention, Alliage surface, Surface alloying, Aleación superficie, Oberflaechenlegieren, Biocompatibilité, Biocompatibility, Biocompatibilidad, Biokompatibilitaet, Composition phase, Phase composition, Composición fase, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Fluence, Fluencia, Homme, Human, Hombre, In vitro, Irradiation ion, Ion irradiation, Irradiación ión, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Nickel alliage, Nickel alloy, Níquel aleación, Nickellegierung, Plasma sanguin, Blood plasma, Plasma sanguíneo, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Siliciure, Silicides, Siliciuro, Silicid, Titane alliage, Titanium alloy, Titanio aleación, Titanlegierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, binary NiTi-base alloy, biocompatibility, corrosion resistance, high-dose ion implantation, silicon, and surface alloying

This paper presents the study on changes in element and phase compositions in the near-surface layer and on surface topography of the NiTi specimens after the silicon ion-beam treatment. The effect of these parameters of the near-surface layer on corrosion properties in biochemical solutions and biocompatibility with mesenchymal stem cells of rat marrow is studied. Ion-beam surface modification of the specimens was performed by a DIANA-3 implanter (Tomsk, Russia), using single-ion-beam pulses under oil-free pumping and high vacuum (10-4 Pa) conditions in a high-dose ion implantation regime. The fluence made 2 × 10 cm-2, at an average accelerating voltage of 60 kV, and pulse repetition frequency of 50 Hz. The silicon ion-beam treatment of specimen surfaces is shown to bring about a nearly twofold improvement in the corrosion resistance of the material to attack by aqueous solutions of NaCl (artificial body fluid) and human plasma and a drastic decrease in the nickel concentration after immersion of the specimens into the solutions for ~3400 and ~6000 h, respectively (for the artificial plasma solution, a nearly 20-fold decrease in the Ni concentration is observed). It is shown that improvement of NiTi corrosion resistance after treatment by Si ions occurs mainly due to the formation of two-layer composite coating based on Ti oxides (outer layer) on the NiTi surface and adjacent inner layer of oxides, carbides, and silicides of the NiTi alloy components. Inner layer with high silicon concentration serves as a barrier layer preventing nickel penetration into biomedium. This, in our opinion, is the main reason why the NiTi alloy exhibits no cytotoxic properties after ion modification of its surface and leads to the biocompatibility improvement at the cellular level, respectively.

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, Corrosion, Corrosión, Korrosion, Dépôt conversion, Conversion coating, Depósito conversión, Konversionsbeschichten, Phosphate, Phosphates, Fosfato, Phosphat, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Préparation surface, Surface preparation, Preparación superficie, Oberflaechenvorbereitung, Prétraitement, Pretreatment, Pretratamiento, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Conversion coatings, Magnesium alloys, Metal phosphates, and Surface pretreatment

This work describes a group of metal phosphate films, including calcium, manganese and strontium phosphate conversion coatings, for corrosion protection of magnesium alloys. These films have been developed by a process that is simple for implementation, chemically stable and non-toxic. The preparation and characterisation of these coatings, along with evaluation of their corrosion performance in 0·1M NaCl, are systematically described. Phase diagram of calcium phosphate was produced to elucidate the coating formation mechanism, which depends upon the chemistry of coating solution, in particular pH and ion concentration. A discussion of the advantages and disadvantages of the coatings is presented, along with perspectives for industrial applications.

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, Corrosion, Corrosión, Korrosion, Indentation, Indentación, Microstructure, Microestructura, Mikrogefuege, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, MAO, Magnesium, Nanoindentation, and Weibull

Ceramic coatings have been developed on AZ31B Mg alloys by micro arc oxidation (MAO) technique, using a mixture of sodium phosphate and sodium fluoride electrolytes. Further, MAO coatings were sealed by the conventional hot water immersion technique. The coatings were characterised by X-ray diffraction, potentiodynamic polarisation, mechanical as well as optical profilometry and nanoindentation techniques. The results showed that the surface roughness and related parameters were always higher after the corrosion test in comparison to as developed MAO coatings, the corrosion resistance of the sealed MAO coatings were enhanced in comparison to unsealed coatings and the MAO coatings had nanohardness ∼10 times and Young's modulus about two times as high as those of the AZ31B Mg alloys. Further, the characteristic scatter in the data was treated by the application of Weibull statistical method. These results are discussed in terms changes in microstructure of the MAO coatings, especially after sealing.

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, Corrosion, Corrosión, Korrosion, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Oxydation, Oxidation, Oxidación, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Chemical conversion, Magnesium alloy, and Microarc oxidation

The dark composite ceramic film was prepared on AZ91D magnesium alloy with a new method which combined chemical conversion with microarc oxidation. Using L16 (45) orthogonal test to optimise the optimum technological conditions of the chemical conversion treatment fluid. The surface morphologies, chemical composition and structure of the film were examined by SEM and XRD. The corrosion resistance performances of the films were investigated by electrochemical measurements (in 3·5 wt-%NaCl aqueous solution). The results showed Zn element was introduced into the microarc oxide ceramic films by chemical conversion pretreatment. The main composition of composite ceramic film was ZnO, ZnO2 and Mg3 (PO4)2 and the surface of the composite ceramic film was smooth, compact and even dark. The saline soaks experiment (72 h) and electrochemical analysis showed corrosion resistance of ceramic film was improved obviously. Adding glycerin can make microarc oxidation reaction more stable and ceramic film of the discharge apertures was smaller. This further increased the density of the film layer and improved the corrosion resistance of the 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, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, A froid, Cold process, En frío, Corrosion, Corrosión, Korrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Formage à froid, Cold forming, Modelado en frio, Kaltformgeben, Oxydation, Oxidation, Oxidación, Procédé dépôt, Deposition process, Procedimiento revestimiento, Beschichtungsverfahren, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, and Cold spray

Cold spray deposition is an emerging technology that addresses many classic shortcomings of more traditional thermal spray processes. Efforts are under way as of this writing to develop a more comprehensive scientific basis for the cold spray process as well as a wider range of suitable materials and its applications for corrosion protection. This paper presents a tutorial introduction to the cold spray coating process, highlighting the coating formation mechanisms, its characteristics and applications. It includes the comparison of cold spray technique with some popular thermal spray techniques. A thorough survey on the combinations of coatings deposited on diverse substrates with their features has also been detailed with emphasis on its applications for oxidation/corrosion protection.

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, Chlore, Chlorine, Cloro, Chlor, Corrosion à chaud, Hot corrosion, Corrosión en caliente, Heisskorrosion, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Superalliage, Superalloy, Superaléación, Superlegierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Coating, and Corrosion

In this work, the NiCrAlY coating was deposited by cold spray deposition technique on Fe based Superfer 800H superalloy. The cold sprayed coating was found to be dense and hard and adhered strongly to the substrate superalloy. In the present investigation, the cyclic hot corrosion behaviour of the coated and bare specimens under the Na2SO4-10%NaCl environment at 900°C is described. It is found that unlike bare superalloy, uniform, dense and adhered scale layer formed on top of the coated specimen. The various characterisation techniques X-ray diffraction, SEM/EDAX and elemental X-ray mapping were used to analyse the corrosion products. It was found that the coating deposited by this coating technique successfully provided protection to the substrate against the hot corrosion degradation by reducing the weight gain of the superalloy.

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.