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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, Dépôt de métaux et d'alliages, Metallic coatings, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Frottement. Usure, Contact of materials. Friction. Wear, Propriété mécanique, Mechanical properties, Propiedad mecánica, Adhérence, Adhesion, Adherencia, Adhaesion, Application, Aplicación, Anwendung, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Erosion, Erosión, Force adhérence, Adhesive strength, Fuerza adherencia, Haftfestigkeit, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Turbine gaz, Gas turbine, Turbina gas, Gasturbine, Usure, Wear, Desgaste, Verschleiss, MCrAlY, abradable coating, adhesive strength, atmospheric plasma spray (APS), erosion resistance, gas turbines, and rubbing wear

The processing conditions, microstructural and tribological characterizations of plasma-sprayed CoNiCrAlY-BN high temperature abradable coatings are reported in this manuscript. Plasma spray torch parameters were varied to produce a set of abradable coatings exhibiting a broad range of porosity levels (34-62%) and superficial Rockwell hardness values (0-78 HR15Y). Abradability tests have been performed using an abradable-seal test rig, capable of simulating operational wear at different rotor speeds and seal incursion rates (SIRs). These tests allowed determining the rubbing forces and quantifying the blade and seal wear characteristics for slow and fast SIRs. Erosion wear performance and ASTM C633 coating adhesion strength test results are also reported. For optimal abradability performance, it is shown that coating hardness needs to be lower than 70 and 50 HR15Y for slow and fast blade incursion rate conditions, respectively. It is shown that the erosion wear performance, as well as, the coating cohesive strength is a function of the coating hardness. The current results allow defining the coating specifications in terms of hardness and porosity for targeted 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, Techniques de l'ingénieur appliqués à la métallurgie. Applications. Divers, Engineering techniques in metallurgy. Applications. Other aspects, Applications, Industrie automobile, Automotive engineering, Adhérence, Adhesion, Adherencia, Adhaesion, Application, Aplicación, Anwendung, Force adhérence, Adhesive strength, Fuerza adherencia, Haftfestigkeit, Industrie automobile, Automobile industry, Industria automóvil, Autoindustrie, Industrie aéronautique, Aeronautic industry, Industria aeronáutica, Luftfahrtindustrie, Morphologie, Morphology, Morfología, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement conducteur, Conductive coating, Revestimiento conductor, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Adhesion testing, aircraft, atmospheric plasma spray (APS), automotive, copper, and electrically conductive coatings

Metallization of Carbon Fiber-Reinforced Polymer (CFRP) composites aggrandized their application to aircraft, automobile, and wind power industries. Recently, the metallization of CFRP surface using thermal spray technique, especially the cold spray, a solid state deposition technique, is a topic of research. However, a direct cold spray deposition on the CFRP substrate often imposes severe erosion on the surface owing to the high-impact energy of the sprayed particles. This urges the requirement of an interlayer on the CFRP surface. In the present study, the effect of surface treatment on the interlayer adhesion strength is evaluated. The CFRP samples were initially treated mechanically, chemically, and thermally and then an interlayer was developed by atmospheric plasma spray system. The quality of the coating is highly dependent on the splat taxonomy; therefore the present work also devoted to study the splat formation behavior using the splat-collection experiments, where the molten Cu particles impinged on the treated CFRP substrates. These results were correlated with the coating adhesion strength. The coating adhesion strength was measured by pull-out test. The results showed that the surface treatment, particularly the chemical treatment, was fairly successful in improving the adhesion strength.

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, Couche mince, Thin film, Capa fina, Duennschicht, Dépôt phase vapeur, Vapor deposition, Depósito fase vapor, Aufdampfen, Dépôt physique phase vapeur, Physical vapor deposition, Deposición física fase vapor, Physikalisches Aufdampfen, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Membrane, Membrana, Membran, Perovskite, Perovskita, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, oxygen transport membrane, perovskite La1-xSrxCoyFe1-yO3-δ, plasma spray physical vapor deposition, porous metallic support, and thin films

Plasma spray physical vapor deposition (PS-PVD) is a very promising route to manufacture ceramic coatings, combining the efficiency of thermal spray processes and characteristic features of thin PVD coatings. Recently, this technique has been investigated to effectively deposit dense thin films of perovskites particularly with the composition of La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF) for application in gas separation membranes. Furthermore, asymmetric type of membranes with porous metallic supports has also attracted research attention due to the advantage of good mechanical properties suitable for use at high temperatures and high permeation rates. In this work, both approaches are combined to manufacture oxygen transport membranes made of gastight LSCF thin film by PS-PVD on porous NiCoCrAlY metallic supports. The deposition of homogenous dense thin film is challenged by the tendency of LSCF to decompose during thermal spray processes, irregular surface profile of the porous metallic substrate and crack and pore-formation in typical ceramic thermal spray coatings. Microstructure formation and coating build-up during PS-PVD as well as the annealing behavior at different temperatures of LSCF thin films were investigated. Finally, measurements of leak rates and oxygen permeation rates at elevated temperatures show promising results for the optimized membranes.

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, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Barrière thermique, Thermal barrier, Barrera térmica, Lanthanide, Lantánido, Nanocomposite, Nanocompuesto, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zirconate, Zirconates, Zirconato, lanthanum zirconate, suspension plasma spray, and thermal barrier coating

This work seeks to develop an innovative nanocomposite thermal barrier coating (TBC) exhibiting low thermal conductivity and high durability compared with that of current TBCs. To achieve this objective, nanosized lanthanum zirconate particles were selected for the topcoat of the TBC system, and a new process—suspension plasma spray—was employed to produce desirable microstructural features: the nanocomposite lanthanum zirconate TBC contains ultrafine splats and high volume porosity, for lower thermal conductivity, and better durability. The parameters of plasma spray experiment included two main variables: (i) spray distance varying from 40 to 80 mm and (ii) the concentration of suspension 20, 25, and 30 wt.%, respectively. The microstructure of obtained coatings was characterized with scanning electron microscope and x-ray diffraction. The porosity of coatings is in the range of 6-10%, and the single phase in the as-sprayed coatings was pyrochlore lanthanum zirconate.

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, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Dopage, Doping, Dopen, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Microstructure, Microestructura, Mikrogefuege, Nanocomposite, Nanocompuesto, Nanostructure, Nanoestructura, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zircone stabilisée, Stabilized zirconia, Zircona estabilizada, La2Ce2O7, nanocomposite coating, nanozones, phonon scattering, and plasma spraying

Nanostructured La2Ce2O7-doped YSZ coatings were developed using atmospheric plasma-spraying technique by optimizing various process parameters. To ensure the retention of nanostructure, the molten state of nanoagglomerates was monitored using plasma and particle diagnostic tools. It was observed that the morphology of the coating exhibits a bimodal microstructure consisting of nanozones reinforced in a matrix of fully-molten particles. The thermal diffusivity of nano-LaCeYSZ coatings is lower than that of nano and bulk YSZ. The reason for this change in thermal diffusivity may be attributed to scattering of phonons at grain boundaries, point defect scattering and higher inter-splat porosity. Also, the thermal conductivity of the nanocomposite coatings was lower than those of nanostructured and bulk YSZ coatings. XRD results show cubic zirconia with a small amount of tetragonal zirconia. The average grain size of the as-sprayed La2Ce2O7-YSZ nanocomposite coatings is -150-200 nm. The improved thermal behavior is mainly due to a dense, packed, and more compact structure 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, Dépôt de métaux et d'alliages, Metallic coatings, Dépôt de matériaux non métalliques, Nonmetallic coatings, Barrière thermique, Thermal barrier, Barrera térmica, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, MCrAlY, Triplex torch, atmospheric plasma spraying, bondcoat, and thermal barrier coating

MCrAlY bondcoats (M = Co, Ni) are used to protect metallic substrates from oxidation and to improve adhesion of ceramic thermal barrier coatings for high temperature applications, such as in land-based and aviation turbines. Since MCrAlYs are prone to take up oxygen during thermal spraying, bondcoats often are manufactured under inert gas conditions at low pressure. Plasma spraying at atmospheric conditions is a cost-effective alternative if it would be possible to limit the oxygen uptake as well as to obtain sufficiently dense microstructures. In the present work, high-velocity spray parameters were developed for the TriplexPro 210 three-cathode plasma torch using MCrAlY powders of different particle size fractions to achieve these objectives. The aims are conflictive since the former requires cold conditions, whereas the latter is obtained by more elevated particle temperatures. High particle velocities can solve this divergence as they imply shorter time for oxidation during flight and contribute to coating densification by kinetic rather than thermal energy. Further aims of the experimental work were high deposition efficiencies as well as sufficient surface roughness. The oxidation behavior of the sprayed coatings was characterized by thermal gravimetric analyses and isothermal heat treatments.

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 titane, Titanium base alloys, Aluminium alliage, Aluminium alloy, Aluminio aleación, Aluminiumlegierung, Cinétique, Kinetics, Cinética, Kinetik, Courbe TTT, TTT curve, Curva TTT, ZTU Schaubild, Etat solide, Solid state, Estado sólido, Fester Zustand, Formage, Forming, Conformado, Umformen, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, Vanadium alliage, Vanadium alloy, Vanadio aleación, Vanadiumlegierung, TTT diagram, Ti-6Al-4V, characterization, heat treatment, net-shape forming, and vacuum plasma spray

Because of the nature of the plasma spraying process, the physical and mechanical properties of vacuum-plasma-sprayed structures of Ti-6AI-4V alloy are completely different from those of conventionally manufactured alloys such as bulk materials from casting and forging. To obtain desired mechanical and physical properties, vacancy and internal defects must be reduced, splat boundaries must be eliminated, and optimal phase compositions should be obtained through postdeposition heat treatments. To determine appropriate heat treatment processes, one needs to study the kinetic behavior of the as-sprayed microstructure at elevated temperatures. In the current study, the kinetics of the solid transformations found in Ti-6AI-4V alloys produced during the vacuum plasma spraying process was studied based on the Johnson-Mehl-Avrami theory. For the kinetic behavior of this alloy, the nonconstant temperature dependence of the transformation rate constant exhibits an irregularity at 900 °C, marking a change in the transformation mechanism. For the lower-temperature (<900 °C) curves, the constant gradient indicates a lack of change in the transformation mechanism, including homogeneous nucleation, with growth of a phase. For higher temperatures (>900 °C), a gradient change indicates a change in the transformation mechanism. The first mechanism was the formation of α-phase grain boundary, and the second mechanism was α-plate nucleation and growth from grain boundaries. The value of the transformation rate constant in the kinetics study of as-sprayed Ti-6AI-4V alloy was much higher than for material produced by the casting method. Using the results obtained from the kinetics of the β → α + β phase transformation at different constant temperatures, a time-temperature-transformation (TTT) diagram for as-sprayed Ti-6AI-4V alloy was developed.

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, Cavitation, Cavitación, Kavitation, Chrome alliage, Chromium alloy, Cromo aleación, Chromlegierung, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Microstructure, Microestructura, Mikrogefuege, Plasma, Projection arc, Arc spraying, Proyección arco, Lichtbogenspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, arc spraying, cavitation, plasma remelting, and strain hardening

Surface remelting is an important technique for modifying the microstructure of thermally sprayed coatings as it reduces the porosity and promotes a metallurgical bond between substrate and coating. Many studies have been carried out in the field of materials selection and surface engineering in an attempt to reduce cavitation damage. In this work, an Fe-Mn-Cr-Si alloy was deposited by arc spraying and then remelted by a plasma-transferred arc process. The base metal was a soft martensitic stainless steel. The influence of remelting current on coating and base metal microstructure and cavitation resistance was studied. The use of a lower mean current and a pulsed arc reduced the thickness of the heat-affected zone. In specimens remelted with constant arc current, dendrites were aligned parallel to the path followed by the plasma torch; while in those remelted with a pulsed plasma arc, the alignment of the microstructure was disrupted. The use of a higher peak current in pulsed-current plasma transferred arc remelting reduced mass loss due to cavitation. Fe-Mn-Cr-Si coatings exhibited cavitation-induced hardening, with martensite formation during cavitation tests. This transformation helps to increase the cavitation resistance of the remelted coating compared with the soft martensitic stainless steel base metal.

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, Barrière thermique, Thermal barrier, Barrera térmica, Basse pression, Low pressure, Baja presión, Niederdruck, Cycle thermique, Thermal cycle, Ciclo térmico, Temperaturverlauf, Durée vie, Lifetime, Tiempo vida, Lebensdauer, Dépôt physique phase vapeur, Physical vapor deposition, Deposición física fase vapor, Physikalisches Aufdampfen, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété thermique, Thermal properties, Propiedad térmica, Thermische Eigenschaft, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, PS-PVD, low pressure plasma spray (LPPS), pre-heating of substrate, thermal cyclic properties, thermal cycling, and vacuum plasma spray

The plasma spray-physical vapor deposition (PS-PVD) process is a promising method to manufacture thermal barrier coatings (TBCs). It fills the gap between traditional thermal spray processes and electron beam physical vapor deposition (EB-PVD). The durability of PS-PVD manufactured columnar TBCs is strongly influenced by the compatibility of the metallic bondcoat (BC) and the ceramic TBC. Earlier investigations have shown that a smooth BC surface is beneficial for the durability during thermal cycling. Further improvements of the bonding between BC and TBC could be achieved by optimizing the formation of the thermally grown oxide (TGO) layer. In the present study, the parameters of pre-heating and deposition of the first coating layer were investigated in order to adjust the growth of the TGO. Finally, the durability of the PS-PVD coatings was improved while the main advantage of PS-PVD, i.e., much higher deposition rate in comparison to EB-PVD, could be maintained. For such coatings, improved thermal cycling lifetimes more than two times higher than conventionally sprayed TBCs, were measured in burner rigs at ∼1250 °C/1050 °C surface/substrate exposure temperatures.

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, Dépôt de matériaux non métalliques, Nonmetallic coatings, Barrière thermique, Thermal barrier, Barrera térmica, Conductivité thermique, Thermal conductivity, Conductividad térmica, Waermeleitfaehigkeit, Céramique, Ceramic materials, Cerámica, Keramik, Frittage, Sintering, Sinterización, Sintern, Impureté, Impurity, Impureza, Begleitelement, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Stabilité thermique, Thermal stability, Estabilidad térmica, Thermische Stabilitaet, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zircone stabilisée, Stabilized zirconia, Zircona estabilizada, atmospheric plasma spray (APS), thermal and phase stability of coatings, thermal barrier coatings (TBCs), thermal conductivity, and zirconia

Dysprosia-stabilized zirconia (DySZ) is a promising candidate to replace yttria-stabilized zirconia (YSZ) as a thermal barrier coating due to its lower inherent thermal conductivity. It is also suggested in studies that DySZ may show greater stability to high temperature phase changes compared to YSZ, possibly allowing for coatings with extended lifetimes. Separately, the impurity content of YSZ powders has been proven to influence high-temperature sintering behavior. By lowering the impurity oxides within the spray powder, a coating more resistant to sintering can be produced. This study presents both high purity and standard purity dysprosia and YSZ coatings and their performance after a long heat treatment. Coatings were produced using powder with the same morphology and grain size; only the dopant and impurity content were varied. Samples have been heat treated for exposure times up to 400 h at a temperature of 1150 °C. Samples were measured for thermal conductivity to plot the evolution of coating thermal properties with respect to exposure time. Thermal conductivity has been compared to microstructure analysis and porosity measurement to track structural changes. Phase analysis utilizing x-ray diffraction was used to determine differences in phase degradation of the coatings after heat treatment.

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 renforcés par dispersion, Dispersion hardening metals, Traitements de surface, 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, Techniques de l'ingénieur appliqués à la métallurgie. Applications. Divers, Engineering techniques in metallurgy. Applications. Other aspects, Applications, Industrie automobile, Automotive engineering, Propriété mécanique, Mechanical properties, Propiedad mecánica, Alliage mécanique, Mechanical alloying, Aleación mecánico, Mechanisches Legieren, Application, Aplicación, Anwendung, Carbure de silicium, Silicon carbide, Silicio carburo, Siliciumcarbid, Céramique, Ceramic materials, Cerámica, Keramik, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Fabrication, Manufacturing, Fabricación, Fertigung, Industrie automobile, Automobile industry, Industria automóvil, Autoindustrie, Industrie aéronautique, Aeronautic industry, Industria aeronáutica, Luftfahrtindustrie, Industrie aérospatiale, Aerospace industry, Industria aeroespacial, Raumfahrtindustrie, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Métal renforcé dispersion, Dispersion strengthened metal, Metal reforzado dispersión, Dispersionsgehaertetes Metall, Nanostructure, Nanoestructura, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, aerospace applications, aluminum alloys, automotive applications, ceramic matrix composite feedstock, mechanical alloying feedstock, nanocomposite feedstock, and wear-resistant coatings applications

6061Al powder with 15 wt.% SiC particulate (SiCp) reinforcement was mechanically alloyed (MA) in a high-energy attrition mill. The MA powder was then plasma sprayed onto weathering steel (Cor-Ten A242) substrate using an atmospheric plasma spray process. Results of particle size analysis and scanning electron microscopy show that the addition of SiC particles as the reinforcement influences on the matrix grain size and morphology. XRD studies revealed embedment of SiCp in the MA-processed composite powder, and nanocrystals in the MA powder and the coating. Microstructural studies showed a uniform distribution of reinforced SiC particles in the coating. The porosity level in the coating was as low as 2% while the coating hardness was increased to 232VHN. The adhesion strength of the coatings was high and this was attributed to higher degree of diffusion at the interface. The wear rate in the coatings was evaluated using a pin-on-disk type tribometer and found to decrease by 50% compared to the 6061Al matrix coating. The wear mechanism in the coating was delamination and oxidative type.

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 nickel, Nickel base alloys, Conception, Design, Diseño, Gestaltung, Electrode, Electrodes, Electrodo, Elektrode, Plan expérience, Experimental design, Plan experiencia, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Ni, atmospheric plasma spray (APS), design of experiment (DOE), electrochemical characterization, and suspension spraying

Ni-based electrode coatings with enhanced surface areas, for hydrogen production, were developed using atmospheric plasma spray (APS) and suspension plasma spray (SPS) processes. The results revealed a larger electrochemical active surface area for the coatings produced by SPS compared to those produced by APS process. SEM micrographs showed that the surface microstructure of the sample with the largest surface area was composed of a large number of small cauliflower-like aggregates with an average diameter of 10 μm.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Décharge étincelle, Spark discharge, Descarga chispa, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Frittage, Sintering, Sinterización, Sintern, Microstructure, Microestructura, Mikrogefuege, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, cold spray, copper, heat treatment, mechanical property, microstructure, and spark-plasma sintering

Cold-spray is well known as an effective coating technique to make thick metallic coatings. However, cold-sprayed metallic coatings usually have low tensile strengths due to low adhesion strength between particles, and low ductility due to low adhesion strength between particles and work hardening. Spark-plasma sintering (SPS) is a pressure-sintering technique that employs a large pulsed direct current. Compared to annealing heat treatment (AHT), SPS is expected to effectively improve the adhesion strength between particles in cold-sprayed metallic coatings. In order to investigate the effects of SPS, cold-sprayed Cu coatings were treated by both SPS and AHT under a wide range of temperatures. The microstructures and mechanical properties of the treated specimens were investigated primarily by scanning electron microscopy, electron backscatter diffraction analysis, hardness tests, and tensile tests. Despite comparable values for porosity, crystal grain size, plastic strain distribution, hardness, and yield stress, the tensile strength and ductility of the specimen treated by SPS at 400 °C (SPS400) were significantly higher than those of the specimen treated by AHT at 450 °C. Based on these results, it was determined that SPS treatment is more effective in improving the adhesion strength between the particles in cold-sprayed Cu coatings than AHT.

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 sec, Dry, En seco, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Nanostructure, Nanoestructura, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété magnétique, Magnetic properties, Propiedad magnética, Magnetische Eigenschaft, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, FeAl, atmospheric plasma spraying (APS), dry-ice blasting, magnetic properties, and nanostructured materials

Amorphous and nanocrystalline materials have attracted much interest in the field of new materials design because of their excellent mechanical and physical properties as well as their magnetic properties. In this work, Fe-40Al coatings were prepared from a nanostructured feedstock by atmospheric plasma spray combined with dry-ice blasting. The scanning electron microscopy, x-ray diffraction, tensile test, and magnetic measurements were used to investigate microstructure, phase structure, adhesion, and magnetic properties of the deposited coatings. The results showed that after using dry-ice blasting, the oxidation and porosity decreased and the atmospheric plasma-sprayed Fe-40Al coatings exhibited a soft ferromagnetic character with lower coercivity and higher saturation magnetization due to their lower degree of order. The plasma-sprayed Fe-40Al coating from the nanostructured feedstock has a very high adhesive 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, 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, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Propriété mécanique, Mechanical properties, Propiedad mecánica, Nanocomposite, Nanocompuesto, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, Mo-alloy, hybrid coatings, nanocomposite, solution precursor plasma spray, and wear resistance

A novel approach hybridizing the conventional atmospheric plasma spraying and the solution precursor plasma spraying techniques has been explored to develop nanocomposite coatings. The above hybrid processing route involves simultaneous feeding of an appropriate solution precursor and commercially available spray-grade powder feedstock to realize microstructures comprising nanostructured and micron-sized features, which are unique in thermal spraying. The attractive prospects offered by this hybrid technique for deposition of nanocomposite coatings are specifically highlighted in this paper through a case study. Plasma sprayed Mo-alloy coatings are known for their good tribological characteristics and widely used in many applications. Further augmentation in performance of these coatings is expected through incorporation of distributed nanostructured oxide phases in the microstructure. Successful development of such coatings using a spray-grade Mo-alloy powder and a suitable oxide-forming solution precursor has been demonstrated. Splat formation under varied processing conditions has been comprehensively investigated and related to microstructure and tribological behavior of the coatings to assess the efficacy of the above nanocomposite coatings for wear resistant 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, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Absorption, Absorción, Application, Aplicación, Anwendung, Diélectrique, Dielectric materials, Dieléctrico, Dielektrisches Material, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Hyperfréquence, Microwave, Hiperfrecuencia, Mikrowelle, Nanocomposite, Nanocompuesto, Nanotube carbone, Carbon nanotubes, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété diélectrique, Dielectric properties, Propiedad dieléctrica, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, carbon nanotubes/cordierite nanocomposite coatings, dielectric property, microwave absorption property, and plasma spray

Multi-walled carbon nanotubes (MWCNTs)/cordierite (MAS) nanocomposite coatings with different MWCNT contents were prepared via atmosphere plasma spraying method. The characteristics of the MWCNTs/MAS powders and as-sprayed coatings, such as microstructure and phase constitution, were observed and measured. The dielectric properties and microwave absorption properties of MWCNTs/ MAS powders and nanocomposite coatings have been investigated at the frequency of 8.2-12.4 GHz with different MWCNT contents and sample thicknesses. When the MWCNT content increased to 7%, the nanocomposite coating revealed the highest dielectric constant and optimal microwave absorption property. Further increase in MWCNT content led to severe oxidation of MWCNTs during the plasma spray process, which resulted in lower dielectric constants and poor microwave absorption property. Moreover, the sample thickness has a noticeable influence on the reflection loss (RL) of the MWCNTs/ MAS coatings, and the coating of 2.4-mm thickness shows optical microwave absorption with a minimum RL of -15.61 dB and bandwidth of 2.35 GHz.

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, Gouttelette, Droplet, Gotita, Modélisation, Modeling, Modelización, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, droplet breakup, modeling, spray parameters, and suspension plasma spray

Suspension feedstock in plasma spraying opened a new chapter in coating process with enhanced characteristics. The suspension carrying sub-micron up to few micron-sized particles is radially injected into an atmospheric plasma plume. Understanding the trajectory, velocity, and temperature of these small particles upon impacting on the substrate is a key factor to produce repeatable and controllable coatings. A three dimensional two-way coupled Eulerian-Lagrangian scheme is utilized to simulate the flow field of the plasma plume as well as the interactions between the evaporative suspension droplets with the gas phase. To model the breakup of droplets, Kelvin-Helmholtz Rayleigh-Taylor breakup model is used. After the breakup and evaporation of suspension is complete, the solid suspended particles are tracked through the domain to determine the characteristics of the coating particles. The numerical results are validated against experiments using high-speed imaging.

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, 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, 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.