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General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Ecoulement gaz, Gas flow, Température, Temperature, Traitement surface, Surface treatments, Cold spraying, Initial pressure differential, Powder carrier gas, and Prechamber

In order to inject powder into the nozzle in cold spraying, the pressure of the powder carrier gas at the nozzle inlet must be equal to or higher than the pressure of the propulsion gas, and the temperature of the powder carrier gas needs to be lower than the temperature of the propulsion gas to prevent from buildup or clogging by particles in the nozzle. The gas flow behavior resulting from the lower temperature and the higher pressure of powder carrier gas has an important effect on the particle acceleration in the nozzle. Several issues related to the gas flow will be examined through numerical simulation, including the initial pressure differential, the nozzle throat diameter, and the prechamber length between the injection tube outlet and the nozzle inlet. For different initial pressure differentials, nozzle throat diameters and prechamber lengths, the mixing conditions of the two gas flow streams in the nozzle are quite different and the negative effect of the inadequate mixing of the two gas flow streams in the nozzle on the particle acceleration is obvious. It is found that using lower differential pressure, larger nozzle throat diameter and longer prechamber for a certain diameter of powder injection tube can enhance the particle acceleration in the nozzle.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Traitements thermochimiques et traitements par diffusion, Thermochemical treatment and diffusion treatment, Surface treatment, Acier non allié, Carbon steels, Activité catalytique, Catalyst activity, Actividad catalítica, Couche mince, Thin films, Dépôt physique phase vapeur, Physical vapor deposition, Magnétron, Magnetrons, Nitruration, Nitridation, Oxyde de titane, Titanium oxide, Titanio óxido, Titanoxid, Plasma, Prétraitement, Pretreatment, Pretratamiento, Pulvérisation irradiation, Sputtering, Traitement surface, Surface treatments, Traitement thermochimique, Thermochemical treatment, Tratamiento termoquímico, Thermochemische Behandlung, Carbon steel, Magnetron sputtering, Photocatalysis, Plasma nitriding, and TiO2

This paper presents a comparative study of TiO2 films deposited on plasma nitrided and non-nitrided carbon steel substrates. It is well known that plasma nitriding contributes to increase film adhesion and corrosion resistance of the substrate. However, most studies about photocatalytic properties of TiO2 on steel substrates do not address the use of nitrided carbon steel. The main goal of this paper is to investigate the deposition of photocatalytic TiO2 film on nitrided carbon steel, obtained through a duplex treatment of plasma nitriding and reactive plasma sputtering deposition. TiO2 films were deposited on nitrided and non-nitrided AISI 1015 steel samples. The samples were characterized by X-ray diffraction (XRD), profilometry, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photocatalytic activity was evaluated by monitoring the effect of photoinduced hydrophilicity and through the degradation of methylene blue dye (MB). The pretreatment by plasma nitriding increases the substrate surface roughness and improves the growth of rutile phase. The roughness of the substrate surface affects wettability only when the TiO2 film is not photoactivated. All samples become super-hydrophilic upon UV irradiation and remaining in this state for at least 24 h. A slightly higher performance in photocatalysis of MB is obtained by TiO2 film deposited on non-nitrided substrate.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Borure de titane, Titanium boride, Titanio boruro, Titanborid, Carbure de titane, Titanium carbide, Titanio carburo, Titancarbid, Electrode, Electrodes, Matériau composite, Composite materials, Qualité, Quality, Calidad, Qualitaet, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatments, Coating parameters, Coating quality, Copper alloy electrode, and Titanium diboride-titanium carbide

To improve the lifetime of electrodes used for the resistance spot welding of Zn-coated steel sheets, a TiB2―TiC composite coating was fused onto the surface of spot welding electrodes using an electro-spark deposition (ESD) process. Different processing parameters were studied in order to improve the quality of the electrode coating. The microstructure, elemental composition, phase structure, and mechanical properties of the coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and microhardness testing. When TiB2―TiC is deposited onto the electrodes in air, extensive coating defects occur within the bulk TiB2―TiC coating and at the interface with the electrode; however, coating defects are significantly reduced when the TiB2―TiC is deposited in argon. Delamination and oxidation of the TiB2―TiC coating were prevented and the number of cracks diminished. When TiB2―TiC was deposited in air on an electrode pre-coated with Ni, almost all coating defects were eliminated. The TiB2―TiC coated directly onto electrodes in air was found to have the lowest average microhardness of HV50 650, and the average hardness values obtained in argon and with Ni-coated electrodes were about HV50 1050 and HV50 1080, respectively. A heat-affected zone (HAZ) of about 20 μm in depth within the substrate was observed near the interface between the coating and the substrate for all coating conditions.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Acier non allié, Carbon steels, Application, Aplicación, Anwendung, Chlorure, Chlorides, Corrosion haute température, High temperature corrosion, Corrosión alta temperatura, Hochtemperaturkorrosion, Elimination déchet, Waste disposal, Haute température, High temperature, Alta temperatura, Hochtemperatur, Incinération, Incineration, Incineración, Indentation, Propriété mécanique, Mechanical properties, Température, Temperature, Traitement surface, Surface treatments, Carbon steel, Instrumented indentation technique, and Municipal solid waste incineration

The effect of exposure temperature on the mechanical properties of scales in a carbon steel was investigated in a simulated waste incineration environment consisting of a gas mixture (N2-O2-H2O-HCl) with samples immersed in a salt (K2SO4-Na2SO4-ZnCl2-KCl) in the temperature range of 573 to 773 K. The microstructure, corrosion rate, elastic modulus (E) and hardness (H) of scales were determined by SEM, XRD, descaled weight loss and instrumented indentation technique. The results indicated that both the E and H decreased as a negative exponential function of temperature, thus obtaining a low mechanical and microstructural integrity of scales with high defect density between 673 and 773 K.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Carbone, Carbon, Couche superficielle, Surface layers, Diamant synthétique, Synthetic diamond, Diamante sintético, Dépôt chimique phase vapeur, CVD, Géométrie, Geometry, Microstructure, Plasma, Structure diamant, Diamond structure, Estructura diamante, Traitement surface, Surface treatments, Diamond-like carbon, Plasma CVD, and Surface topography

Potential applications of diamond-like carbon (DLC) coatings range from precision tools and biomedical implants to micro mechanical devices and engine components. Where uniform coatings are required on substrates with complex geometries, plasma enhanced chemical vapour deposition (PECVD) is often a preferred deposition method. As a non-line of sight process, the geometry of the substrate is often considered negligible. For this reason analysis of PECVD coatings, such as amorphous carbon, has mostly been concerned with reactor deposition variables, such as bias voltage, pressure and gas ratios. Samples are therefore usually prepared and positioned to minimise the influence of other variables. By depositing nominally similar DLC films on silicon samples positioned horizontally and vertically on the reactor cathode plate it was possible to examine the variations in the coating characteristics and mechanical properties that occur due to the geometry of the substrate being coated. Topographic measurements and analysis of bonding structures revealed significant heterogeneity in the coatings. Electron microscopy showed variation in surface structure as well as thickness disparities of up to 50% in the vertical sample. Atomic force microscopy showed roughness, Ra, varied from 0.37 nm to 15.4 nm between samples. Raman spectroscopy highlighted variations in the sp2/sp3 bonding ratios whilst micro wear tests demonstrated how these variations reduce the critical load performance. These effects are explained in terms of the deposition mechanisms involved and are related to variation in deposition species and geometrical field enhancements within the deposition chamber. Improved understanding of these local variations will aid in the optimisation of coatings for complex substrate geometries.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base aluminium, Aluminium base alloys, Corrosion, Dépôt conversion, Conversion coating, Depósito conversión, Konversionsbeschichten, Revêtement, Coatings, Température, Temperature, Traitement surface, Surface treatments, Aluminum 2024, Nanosilica, and Silicate conversion coatings

Nanosilica modified potassium silicate conversion coatings were deposited on the surface of 2024 aluminum alloy. The corrosion behavior of coatings was studied by electrochemical impedance spectroscopy, potentiodynamic polarization and the surface analyzing techniques. The effect of curing time and the curing temperature was studied on anti-corrosion behavior of coatings. Curing temperature showed a significant effect in silicate conversion coating and higher corrosion resistance was obtained with 150 °C curing temperature. Also the experimental results indicated that the corrosion resistance was increased with increasing the curing time. This behavior can be related to the increase of the silicate coating continuity and reinforcement of the siloxane chains which formed on the surface. Surface analysis results indicated that the coating obtained from 2.33 silica ratio was more uniform and continuous.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Alliage base magnésium, Magnesium base alloys, Dépôt projection, Spray coatings, Matériau composite, Composite materials, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatments, Cold spray, Magnesium alloys, and Mechanical property

Although many previous studies have confirmed that cold sprayed Al + xAl2O3 (x = 0―75 vol.%) composite coatings on magnesium alloys can effectively improve wear and corrosion resistance, the effect of such coatings on tensile and fatigue properties is still unclear. The present work aims to evaluate the tensile properties and fatigue resistance of an AZ91D alloy with cold sprayed Al + xAl2O3 (x = 0,30, 50 vol.%) coatings. The experimental results showed that although the cold spray coating leads to an increase in yield strength and fatigue limit, the tensile strength is reduced. In-situ examination of the macro-morphology of surfaces of the coated specimens during tensile testing was carried out through video recording. It indicated that once the tensile specimens have yielded, horizontal cracks that were perpendicular to the tensile axis formed on the surface of the specimens. Fractographic analysis of the fracture surfaces of the tensile specimens in a scanning electron microscope revealed that all the cracks within the cold sprayed coatings were suspended at the coating/substrate interface. Based on these experimental observations, it is considered that the improved yield strength is attributed to the constraint effect of the cold sprayed composite coatings on the magnesium substrate. The enhanced fatigue limit is a result of the higher yield strength and the coating/substrate interface barrier to crack propagation. The decrease in tensile strength is attributed to the brittle fracture of the cold sprayed coatings when yielding of the specimens.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, 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, Oxyde de titane, Titanium oxide, Titanio óxido, Titanoxid, Procédé sol gel, Sol-gel process, Température, Temperature, Traitement surface, Surface treatments, Tribologie, Tribology, Usure, Wear, CP-Ti, Calcination, Sol-gel, and TiO2

Commercially pure titanium (CP-Ti) is commonly used as an implant material especially for orthopedic and dental treatments in biomedical applications. This material shows insufficient tribological properties. Some surface treatments were applied on surface CP-Ti in order to improve tribological properties of the CP-Ti. Among these techniques, sol-gel coating process was used for this purpose. In this study, CP-Ti was coated by TiO2 film with sol-gel dip coating process. Coated samples were calcined at the various temperatures. The effects of calcination temperature on the wear performance of the coated films were observed. It was observed that the hardness, elastic modulus, surface roughness, friction coefficient and wear resistance values of coated samples were higher than the uncoated CP-Ti values. Also, these properties of coated samples increased with increasing of calcination temperature. The intensity of the rutile-TiO2 phase increased with the calcination temperatures. It was determined that rutile-TiO2 structure showed self-lubrication like behavior. The best tribological properties were obtained from the sample calcinated at 900 °C.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Autres traitements de surface, Other surface treatments, Alliage base aluminium, Aluminium base alloys, Anodisation, Anodizing, Conception, Design, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Microstructure, Oxydation, Oxidation, Oxyde anodique, Anodic oxide, Traitement surface, Surface treatments, Vieillissement, Aging, Aluminum anodizing, Bath aging, Oxide layer microstructure, and Pore design

During the aluminum anodization the anodizing electrolyte changes over time and is well-known as bath aging. This alteration of the bath is mainly caused by the impact of Al3+ ions and ions of alloying elements as well as the consumption of protons. It is shown that the higher the Al3+ concentration the higher the pH value and the electrical resistance of the bath. Consequently, the oxide formation rate decreases, whereby the efficiency of layer formation increases. This work is focused on the effect of the ongoing bath aging on the microstructure of the anodic oxide layers formed on AA1050. It illustrates the fact that the ongoing bath aging significantly influences the morphology, the thickness and the pore structure of the oxide layers that are formed, but does not influence the barrier layer thickness. The pore diameter decreases with ongoing bath aging. As a direct consequence the hardness of the oxide layer increases and the pore diameter decreases.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Air, Alliage base nickel, Nickel base alloys, Développement, Ontogenesis, Microstructure, Oxydation, Oxidation, Pile combustible oxyde solide, Solid oxide fuel cells, Revêtement, Coatings, Superalliage, Superalloys, Traitement surface, Surface treatments, Electron microscopy, Nickel base superalloy, and Solid oxide fuel cell interconnects

The effect of reactively sintered Mn1.5Co1.5O4 (MCO) coatings on the development of surface microstructure for Haynes 230 (H230) oxidized in air at 800 °C has been studied using a combination of thermo-gravimetric analysis and electron microscopy techniques. The bare alloy exhibits a parabolic rate constant of 8.8 × 10―9 mg2cm―4 s―1 and forms a two-layer oxide scale with a continuous chromia layer and a thinner discontinuous MnCr2O4 overlayer. For the MCO-coated H230, the reduction step of the reactive sintering process converts the MCO coating to a mixture of Co and MnO with a thin Cr-rich oxide layer at the interface with the alloy substrate. Following the re-oxidation step, there is a 200 nm chromia layer and a 400 nm cubic spinel reaction layer (RL) between the alloy and the MCO. These layers thicken to 800 nm and 1.2 μm, respectively after 1000 h oxidation. These observations are compared to our previous studies of MCO-coated Crofer 22 APU, and the implications for long-term SOFC performance are discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Céramique, Ceramics, Oxydation, Oxidation, Oxyde de zirconium, Zirconium oxide, Zirconio óxido, Zirconiumoxid, Plasma, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatments, Ceramic coating, PEO, Plasma electrolytic oxidation, and Pure zirconium

The pure zirconium metal was coated by plasma electrolytic oxidation in silicate containing basic electrolyte for the cumulative periods of 5, 10, 20, 30, 45, 60, 90, and 120 min successively for the total coating duration of 120 min. The phase content, surface morphology and chemical composition of the PEO coating were characterized by XRD, SEM and profilometry after each coating time successively. The equiaxed clusters unique to Zr were formed on the surface of the coating. The number of plasma channels decreased but the sizes and intensities of the sparks increased by increasing the process duration and consequently the amount of materials ejaculated through these channels increased. The thickness and the surface roughness of the coating were increased by the process duration. The presence of cracks and pores resulted in a lower value of microhardness of the coating compared to the theoretical value of ZrO2. The plasma channels containing Si rich and radially grown Zr rich crystals were clearly observed from the cross sectional examination of intentionally created fracture surface. The characterizations carried out upon successive coating and successive removal of this coating confirmed that monoclinic ZrO2/tetragonal ZrO2 ratio was not changing with coating thickness.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Corrosion, Action des agents de corrosion, Corrosion environments, Adhérence, Adhesion, Corrosion, Dépôt physique phase vapeur, Physical vapor deposition, Magnétron, Magnetrons, Pulvérisation irradiation, Sputtering, Résistance corrosion, Corrosion resistance, Traitement surface, Surface treatments, High power pulsed magnetron sputtering, Tensile strain, and Ti-O film

In order to explore the potential application on cardiovascular stent, titanium oxide films were fabricated on CoCrMo alloy substrate by high power pulsed magnetron sputtering (HPPMS). The effect of Ti interlayer and thickness of Ti-O film on the film adhesion was investigated by the scratch test and tension test. After different tensile strain, the corrosion behavior of Ti-O coated CoCrMo alloy and bare CoCrMo alloy was also investigated by polarization tests. The results showed that the deposition of Ti interlayer can obviously improve the film adhesion and the film adhesion decreased with film thickness increase. In addition, the 30 nm Ti-O film with 10 nm Ti interlayer had excellent adhesion and it could withstand 30% relative elongation without obvious delamination. The corrosion resistance of Ti-O coated CoCrMo alloy was superior to bare CoCrMo alloy after different tensile strain. Due to its good adhesion and corrosion resistance after different tensile strain, the HPPMS Ti-O film had a potential application on CoCrMo alloy cardiovascular stent surface modification.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Calorimétrie, Calorimetry, Composé intermétallique, Intermetallic compounds, Développement, Ontogenesis, Effet température, Temperature effects, Microscopie électronique balayage, Scanning electron microscopy, Microstructure, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Température, Temperature, Traitement surface, Surface treatments, Aluminide miscellaneous, Aluminium, and Thermal spraying

In this work, the authors have used an unconventional experimental route that consists of (i) deposition of a nickel coating onto an aluminium substrate and (ii) the subsequent heat treatment of created couple in order to produce intermetallic-layered structures, hypereutectic or bulk aluminide intermetallic alloys. The procedure was conducted by controlling chemical concentrations in the Al-rich corner of Al-Ni binary system. The couple was prepared by high velocity oxyfuel spraying of 99.0 wt.% Ni powder onto the surface of 99.999 wt.% Al sheet. The specimens for heat treatment were manufactured immediately after the spraying. The heat treatment was carried out in a differential thermal analysis apparatus by using the temperature range of 600―1200 °C, thus considering the solid state, transient liquid as well as liquid phase of aluminium, with a constant heating/cooling rate of 5 °C/min in an argon atmosphere. Microstructural development of produced alloys was studied by conventional metallography and scanning electron microscopy. Formed intermetallic layers and compounds were evaluated by using energy dispersive microanalysis and image analysis techniques. The development of a novel ultra-fine eutectic alloy is reported.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Chrome, Chromium, Contrainte résiduelle, Residual stresses, Effet température, Temperature effects, Nitrure de chrome, Chromium nitride, Cromo nitruro, Chromnitrid, Nitrure de titane, Titanium nitride, Titanio nitruro, Titannitrid, Procédé dépôt, Deposition process, Procedimiento revestimiento, Beschichtungsverfahren, Propriété mécanique, Mechanical properties, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Température, Temperature, Traitement surface, Surface treatments, Tribologie, Tribology, Cathodic arc deposition, Superlattices, Titanium and chromium nitrides, and Tribological properties

Nanolayered TiN―CrN coatings were synthesized by cathodic arc deposition (CAD) on M2 tool steel substrates. The aim of this study was to establish a double-correlation between the influence of the bilayer period and the deposition temperature on the resulting mechanical―tribological properties. The superlattice hardening enhancement was observed in samples deposited at different temperatures ― i.e. without additional heating, 300 °C and 400 °C. Nonetheless, the residual compressive stresses are believed to be the responsible for reducing the hardness enhancement when the deposition temperature was increased. For instance, sample deposited without additional heating presented a hardness of 48.5 ± 1.3 GPa, while by increasing the processing temperature up to 400 °C it was reduced down to 31.2 ± 4.1 GPa due to the stress relaxation. Indeed, the sample deposited at low temperature which possesses the thinnest bilayer period (13 nm) exhibited better mechanical properties. On the contrary, the role of the interfaces introduced when the period is decreased seems to rule the wear resistance.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Déformation, Deformation, Dépôt projection, Spray coatings, Effet température, Temperature effects, Propriété mécanique, Mechanical properties, Sensibilité vitesse déformation, Strain rate sensitivity, Sensibilidad velocidad deformación, Dehngeschwindigkeitsempfindlichkeit, Température, Temperature, Traitement surface, Surface treatments, Vitesse déformation, Strain rate, Cold spray, Copper, Impact deformation, and Smoothed particle hydrodynamics

Cold spray is a manufacturing process that has proved to be a valuable technique for producing high strength metallic coatings. It has been extensively studied in recent years, both experimentally and computationally. Among the various modelling investigations in the literature, a large number have considered the problem of a single particle impacting a substrate by means of a continuum technique, most commonly the finite element method. These models that have been used previously are generally based on two inadequate assumptions, namely 1) both particle and substrate are assumed to initially be at room temperature, and 2) the experimentally observed increase in strain rate sensitivity of the flow stress at high strain rates is ignored. To investigate the combined effect of temperature and strain rates, a three-dimensional model of a single particle impact with a metallic substrate has been developed using smoothed particle hydrodynamics. This meshless method is ideally suited to the simulation of cold spray as very large material deformations can be readily accommodated, whereas this is often a significant difficulty in mesh based techniques. A Cu-on-Cu impact was considered and quantitative comparisons with experimental cross-sections were conducted. It was found that predictions within 5% of the experimental data could be achieved only when both the softening effect due to the initial thermal field and the hardening effect due to the very high strain rates were included in the model. In contrast ignoring these effects led to results that had as much as 50% variation compared to experiments. The model described in this paper is a robust tool that will enable quantitative predictions of cold spray impacts and help further optimise the process.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, 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, Adhérence, Adhesion, Couche mince, Thin films, Dureté, Hardness, Elasticité, Elasticity, Module Young, Young modulus, Module élasticité, Elastic modulus, Propriété mécanique, Mechanical properties, Traitement surface, Surface treatments, Tribologie, Tribology, Usure, Wear, Tantalum oxynitride, Wear behavior, and Young's modulus

Tantalum oxynitride (TaNxOy) thin films were produced by magnetron sputtering. This work analyzes and compares the mechanical properties and the wear behavior of the films, taking into account the differences promoted by changes in composition and structure, caused by the variation of the partial pressure of the reactive gases (P(N2 + O2)) and by the polarization of the substrate holder. Besides the change in composition, the variation of P(N2 + O2) causes significant changes in the morphology and structure of the films. Those produced with low P(N2 + O2) evidence a higher crystallinity and, in these conditions, the films exhibit hardness around 20 GPa. Films produced with higher P(N2 + O2) exhibit higher O content, are amorphous and the hardness is significantly lower. The substrate bias does not influence the adhesion of the films to the high speed steel substrate, but influences the mechanical properties, particularly the hardness, at low P(N2 + O2) regime. Films with higher crystallinity exhibit higher hardness, but in the low P(N2 + O2) regime, those who were produced with polarization are harder. Although some dependence may be established for set B films, the hardness is not as influent on the wear resistance of the TaNxOy films as the friction coefficient.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Couche mince, Thin films, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Etat solide, Solid state, Estado sólido, Fester Zustand, Modélisation, Modelling, Méthode élément fini, Finite element method, Oxydation, Oxidation, Oxyde de cobalt, Cobalt oxide, Cobalto óxido, Cobaltoxid, Oxyde de cuivre, Copper oxide, Cobre óxido, Kupferoxid, Propriété mécanique, Mechanical properties, Propriété physicochimique, Physicochemical properties, Propiedad fisicoquímica, Recuit, Annealing, Revêtement, Coatings, Traitement surface, Surface treatments, Traitement thermique, Heat treatments, Copper―cobalt oxides, Finite element modeling, Solid state ionics, and Thin film coating

Sol―gel dip-coated optical coatings, copper―cobalt oxides on aluminum substrates, were thermally treated at different annealing temperatures in the range 500―650 °C. The resulting films were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV―Vis―NIR spectrophotometry and nanoindentation techniques. The crystallinity of CoCu2O3 enhanced significantly, with increasing annealing temperature from 500 to 650 °C, while the electronic structure and bonding states of the copper―cobalt oxides matrix remained unchanged. UV―Vis―NIR analysis showed that the solar absorptance (α) of the coatings changed with increase of annealing temperature and an optimum α (84.4%) was achieved at 550 °C, which also coincides to the maximum tensile residual stress of the coating. Nanoindentation tests exhibited an increasing trend in both the hardness (H) and elastic modulus (E) of the coatings with increase in annealing temperature, although a slight decrease in the H/E ratio was also observed. The experimental studies were complemented by finite element modeling (FEM). The results showed that, under mechanical loading, the stress deformation and plastic deformation were concentrated within the coating layers. As such, the likelihood of delamination of the coating layer upon unloading would be reduced.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Dépôt électrophorèse, Electrophoresis coating, Depósito electrofóresis, Elektrophoretisches Beschichten, Matériau composite, Composite materials, Revêtement composite, Composite coating, Revestimiento compuesto, Solubilité, Solubility, Traitement surface, Surface treatments, Chitosan, Composite coatings, Degradation, Drug eluting, Electrophoretic deposition, and Gelatin

We prepared chitosan―gelatin (Chi―Gel) composite coatings on Ti via electrophoretic deposition (EPD) method for utilization in tissue repair and drug delivery. Uniform coatings were produced over a wide compositional range (0―75% Gel) with coating gains dependent on the EPD parameters including voltage and time. Coating degradation increased as the Gel content increased, with 16―54% weight losses after 3 weeks of immersion in phosphate buffered saline. Ampicillin, used as a model drug, was successfully incorporated within the coatings during the EPD process, and the release was highly sustainable with no burst effect up to a month, proving the potential of these materials as long-term drug eluting coatings. The release rate was dependent on the coating degradation, i.e., the more degradable with increasing Gel content, suggesting a rate-controllable drug release by a compositional change. Preliminary cell tests showed favorable cell adhesion and spreading on the composite coatings, with significant improvement in cell proliferation as Gel content increased. While more in-depth biological assays remain, the Chi―Gel might be useful as a drug eluting electrophoretic coating system on metallic implants for tissue repair.

General chemistry, physical chemistry, Chimie générale, chimie physique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Acier inoxydable, Stainless steels, Extraction, Oxydation, Oxidation, Plasma, Pyrolyse, Pyrolysis, Revêtement, Coatings, Traitement surface, Surface treatments, Extraction-pyrolysis method, Oxide coatings, Plasma electrolytic oxidation, Stainless steel, Ta2O5, and Titanium

Coatings with up to 20 at.% of tantalum and phases of Ta2O5, Ta2O5 • TiO2, and TiO2 have been formed on titanium in an aqueous electrolyte containing NH4[TaF6] by means of the method of plasma electrolyte oxidation (PEO). The addition of ethylene glycol into the electrolyte enables one to change the morphology and phase composition of resulting coatings. By combining the PEO and extraction-pyrolysis (EP) methods, layered coatings composed, in the upper part, of alternating elevations with predominant content of tantalum oxides and lows containing titanium oxides and calcium phosphates. The sizes of elevations and lows are about 10 μm. Layers consisting predominantly of tantalum oxides of a thickness of 3 μm have been formed on stainless steel by means of the EP method. The composition and structure of the obtained coatings make it possible to recommend their use in tests as biocompatible or bioinert media for deposition on titanium or steel implants, stents, or catheters.