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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, Traitements de surface, Surface treatment, Argent, Silver, Plata, Silber, Choc laser, Laser impact, Choque laser, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Cold spray, Composite, Laser shock, Oxide, Powder, Splat, and Tantalum

Since the major technological issues in cold spray are now controlled, the key parameter for successful coating relates to the powder. The influence of the main characteristics of the starting powder on the final coating properties remains rather unknown. This includes primarily metallurgical, morphological and physico-chemical characteristics of the particles. This article focuses on the so-called local approach to these characteristics to show that the current global approach is insufficient. The discussion is based on many examples of cold spray results, including recent work on Ag-based and Ta cold sprayed-coatings. This results in proposed specifications for powders which are claimed to be tailored for cold spray.

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, 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, A froid, Cold process, En frío, Dynamique fluide, Fluid dynamics, Dinámica fluido, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Formage à froid, Cold forming, Modelado en frio, Kaltformgeben, Préchauffage, Preheating, Precalentamiento, Vorwaermen, Revêtement, Coatings, Revestimiento, Ueberzug, Simulation numérique, Numerical simulation, Simulación numérica, Température, Temperature, Temperatura, Temperatur, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Carrier gas, Coating, Cold spray, and Computational fluid dynamics

Carrier gas is known as the medium to inject the cold sprayed powders into the main driving flow inside the nozzle. Hence, the properties and conditions of carrier gas should be of great importance to the particle motion behaviour and then particle deposition process. In this study, the effect of carrier gas temperature on the particle acceleration and deposition in cold spray process was investigated by both numerical and experimental methods. It is found that the supersonic driving gas flow and the consequent particle acceleration behaviour are significantly influenced by the carrier gas temperature, more specifically, higher carrier gas temperature results in higher particle impact velocity. In addition, because the carrier gas has additional heating effect on the powder particles before injection, the final impact temperature also increases with the carrier gas temperature, which leads to the reduction in the critical velocity. The increase in particle impact velocity and reduction in critical velocity enable the deposition efficiency and coating bonding strength to significantly improve as the carrier gas temperature increases. The particle impact velocity is found to be more influential than critical velocity reduction.

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, Cémentation caisse, Pack carburizing, Cementación en paquete, Pulveraufkohlen, Dépôt chimique phase vapeur, Chemical vapor deposition, Depósito químico fase vapor, Chemisches Aufdampfen, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Oxydation, Oxidation, Oxidación, Protection, Protección, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Chemical vapour deposition, SEM, TG, and XRD

The growth of Mg and Al coatings on copper by pack cementation is examined in this work by investigating the mechanism of the process, the effect of temperature and heating time on the coating structure. The experiments were undertaken at temperatures ranging from 550 to 600°C, while the duration of the process varied from 30 min to 3 h. It was found that the magnesium coatings consist of two phases corresponding to MgCu2 and CuMg2. These phases appeared as distinguished layers or mixed with each other, depending on the deposition temperature and duration. On the other hand, the aluminium coatings consist of a single Al4Cu9 phase whose thickness increases with deposition time and temperature. Finally, the oxidation resistance was also evaluated by thermogravimetric measurements, which revealed that the coated samples have superior resistance to bare copper, while Al coated coupons had the best performance when exposed in high temperature environment.

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, Alliage base aluminium, Aluminium base alloys, Alliage base magnésium, Magnesium base alloys, 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, Aluminium, Coating, Magnesium, Optimisation, and Spray

Cold spray technology continues to attract increasing attention in surface modification of light metals due to its low temperature operation. A method for selecting optimum process parameters is presented for cold spraying of aluminium coatings upon magnesium alloy AZ91. In the present study, particle deposition behaviour is investigated via modifying spraying parameters. Subsequently, based on the relationship between bonding ratio and particle velocity, the critical particle velocity for successful adhesion is determined. Finally, the influence of particle velocity on key coating characteristics is examined, including coating porosity, hardness, deposition efficiency and bond strength.

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, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Microstructure, Microestructura, Mikrogefuege, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Coating microstructure, Kinetiks, MRO, Nickel alloys, PCS-1000, and Waspaloy

The deposition of pore free and highly adhered Ni and Co superalloy coatings is of great interest for engine design and gas turbine applications, both in case of maintenance repair and overhaul operations as well for mechanical and chemical protection purposes in aeronautics and energy applications. This study would like to give a wide overview about the capability of cold spray technology on this topic: two different commercially available deposition systems, Sulzer-CGT Kinetiks 4000 and Plasma Giken PCS-1000, were compared, and deposition processes with both nitrogen and helium as carrier gas have been explored. Microstructural investigation, microhardness and adhesion results are reported to depict a preliminary scenario of coating properties. Fully dense coatings with thickness >1 mm and adhesion >50 MPa are obtained using helium, while quite porous, 20 MPa adhered coatings are obtained using nitrogen. Finally, general considerations about the potential applicability of those coatings for repair purpose in aerospace applications are pointed out.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rupture, Ruptura, Bruch, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, Cold spraying, Critical velocity, and Impact behaviour

Cold spraying (CS) is a coating technique, which has developed rapidly in the last two decades and shows great potential in the industrial community due to its advantages of low temperature deposition as well as no oxides forming in the coating. This review's focus is on the behaviour of particles impacting and the prediction of critical velocity for particle deposition during CS as calculated by numerical simulations according to the open literature. The first part presents an introduction of CS and its particle bonding mechanism. The second part briefly introduces the typically employed numerical computation methods and compares these methods. The third part discusses the effect of particle parameters on particle deformation behaviour. Finally, the current problems and prospects existing in numerical simulations of the impact of CS particles are explored.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Microstructure, Microestructura, Mikrogefuege, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Biodegradable Mg, Coating, Mechanical behaviour, Scaffold, and Tissue engineering

In recent years, attention has been focused on the magnesium (Mg) as a promising material in biodegradable metallic scaffolds for bone tissue engineering. Since an orthopedic scaffold is supposed to repair and regenerate fractured bones, its mechanical integrity is vital throughout the healing process. In this study, a biocompatible polymeric layer made of polycaprolactone (PCL) in different concentrations of 3% w/v and 6% w/v was coated on the surface of Mg scaffolds. The structural characteristics and mechanical behaviour of the Mg scaffolds during the immersion in physiological saline solution (PSS) were investigated. According to our results, the PCL coating hindered the diminution of mechanical stability of scaffolds to provide adequate support for bone healing. Specifically, scaffold coated with 3% w/v and 6% w/v PCL demonstrated 24 and 100% improvement in the elastic modulus and 41 and 83% enhancement in compressive strength respectively, after 24 h immersion in PSS, compare to the uncoated scaffold. Thus, PCL coating of Mg scaffolds may be a promising approach in the development of mechanically stable bone scaffolds.

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, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Modélisation, Modeling, Modelización, Métaux dissemblables, Dissimilar metals, Metales desemejantes, Verschiedenartige Metalle, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Bonding, Cold spray, Impact, Modelling, and SPH

In this study, the critical, maximum and optimum velocity of a single cold sprayed (CS) particle is estimated using the smoothed particle hydrodynamics (SPH) method by evaluating the impact shape coefficient of restitution, as well as the rebound and deposit energy ratio. The contact surfaces of the particle and the substrate are modelled as intersurface forces using the Dugdale-Barenblatt cohesive zone model. The application of SPH allows the simulation of the CS process without the use of mesh, thereby avoiding the disadvantages of the traditional numerical method in handling large deformations and tracing moving interfaces. The impact of CS particles is simulated using various powder and substrate materials. The influence of the materials on the optimum velocity and the coating quality is discussed. The reliability of the model is verified with CS experiments.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Erosion, Erosión, Modélisation, Modeling, Modelización, Méthode élément fini, Finite element method, Método elemento finito, Finite Element Methode, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rupture, Ruptura, Bruch, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, Cold spray, Euler, FEA, Multimaterial, and Multiparticle

Finite element analysis on the high velocity impact behaviour in cold spraying is conducted using the Euler method. The simulation results demonstrate that the Euler method is capable of realising the reliable simulation on some complicated impact processes. The comparative deformation ratio (CDR) is proposed, which is defined as the ratio of dimensionless crater depth to compressional ratio, to evaluate the comparative deformation degree between the particle and substrate. Proper CDR and sufficiently large compressional ratio can ensure the well bonding between the particle and substrate. Furthermore, for the multiparticle impact process, it is found that, after the deposition of the first layer coating, the subsequent impact process can be considered as particles impacting on the same material no matter what substrate is coated. When the velocity is increased to a hypervelocity (erosion velocity), extreme erosion occurs in the substrate or the formed coatings, resulting in the poor performance of the coating.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Déformation, Deformation, Deformación, Verformung, Propriété mécanique, Mechanical properties, Propiedad mecánica, Préchauffage, Preheating, Precalentamiento, Vorwaermen, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Cold spraying, and Deformation behaviour

The present paper used an Eulerian model to study effects of the substrate material and the substrate temperature on the particle deformation behaviour in cold spraying dissimilar particle/substrate combinations. Results show that the deformation pattern of the particle presents a spreading and penetration way for soft/hard and hard/soft particle/substrate material combinations respectively. In addition, preheating the substrate can achieve a coordinated deformation pattern for the soft/hard particle/substrate material combination and a maximum steady PEEQ ranging in 3·2-3·5 in the present study.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Etat surface, Surface conditions, Estado superficie, Oberflaechenzustand, Alliage base aluminium, Aluminium base alloys, Couche mince, Thin film, Capa fina, Duennschicht, Dureté, Hardness, Dureza, Haerte, Epaisseur, Thickness, Espesor, Dicke, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, and Amorphous

This work explored the effect of deposition pressure on the properties of the ternary AI―Mg―B thin films deposited on Si substrate at high deposition temperature (600°C) by magnetron sputtering system with one pure boron target and one Al/Mg co-target. The influences of the deposition pressure on the elemental contents, deposition rate, surface roughness, structure and mechanical properties were investigated by Electron microprobe analysis (EPMA), 3D surface profiler, X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and nanoindentation experiments respectively. Experimental results indicated that the amorphous thin films deposited at 0·5 Pa had a smooth surface and displayed the maximum hardness and Young's modulus of 35 and 322 GPa respectively. From the results of this work, high quality Al―Mg―B hard thin films can be obtained by magnetron sputtering under an optimum deposition pressure of 0·5 Pa.

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, Calcul, Calculation, Cálculo, Berechnung, Conception, Design, Diseño, Gestaltung, Dynamique fluide, Fluid dynamics, Dinámica fluido, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Efficacité, Efficiency, Eficacia, Wirkungsgrad, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, CFD, Cold spray, Deposition efficiency, Nozzle design, Particle velocity, and Titanium coatings

Coating technologies play a critical role in the worldwide manufacturing industry. The ability to form layers of specific materials onto engineering components to enhance mechanical and physical properties has numerous applications, ranging from corrosion protection, repair, hardfacing, down to purely aesthetic purposes. Cold spray is an innovative technology, which allows for the manufacturing of coatings in a solid state manner; hence, feedstock properties can be fully preserved. Its working principles relies upon the acceleration of powders up to supersonic velocities, and the subsequent generation of high energy impacts on a substrate which triggers the coating formation. This paper presents deposition efficiency (DE) results from four different supersonic nozzles when using titanium as feedstock material. DE is the most critical parameter to assess the performance of cold spray nozzles. A theoretical analysis through computational fluid dynamics (CFD) is carried out so to compare numerical results against experimental findings. Results have suggested that current commercial codes cannot accurately predict the acceleration process under realistic working conditions. It is therefore difficult to predict DE levels. Cold Spray is starting to be applied to high end engineering; however, it is likely not to be successful unless critical understanding is generated and used to accurately design nozzles, and predict the performance of new prototypes.