bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deposition Characteristics of Fe/Al Composite Coating Fabricated by Cold Spraying
Authors: Wang H. , Li C. , Yang G. , Li C. , Gao P. , Zhang Q. 
Published: September 2022

Abstract
FeAl Intermetallic compounds have excellent wear resistance and high temperature oxidation resistances. The low temperature brittleness makes intermetallic compound materials more suitable to be applied in the form of coating to protect materials from high temperature oxidation and wear. In the present study, a iron/aluminum composite coating was produced by cold spraying of iron and aluminum powder mixtures and then was annealed at different temperatures to aim at forming an iron aluminide intermetallic based coating. The deposition behavior of iron and aluminum powder mixtures and microstructural characteristics of the as-sprayed deposit were examined by scanning electron microscopy (SEM). The kinetics of the phase transformation of the as-sprayed iron/aluminum composite deposit to iron aluminide was characterized by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results showed that after heat treatment at a temperature of 600°C, intermediate phase Al5Fe2 coexisted in the deposit with remaining Fe and Al. With increasing heat treatment temperature to 900°C, the deposits consisted of mainly FeAl phase and a trace of remaining Fe phase.
Fabrication of TiO2 Coating by Cold Spraying and Evaluation of Its Property
Authors: Yamada M. , Wada H. , Sato K. , Fukumoto M. 
Published: September 2022

Abstract
Titanium dioxide (TiO2) is a promising material for photocatalyst coating. However, it was difficult to fabricate TiO2 coatings which have excellent photocatalyst property by thermal spray processes. Because anatase phase of TiO2 transforms into rutile phase under high temperature i.e. the photocatalyst property of TiO2 declines by heating. In this study, TiO2 photocatalyst coatings were fabricated by cold spraying. Agglomerated TiO2 powder with 100% anatase phase was injected into nitrogen or helium gas stream and deposit onto steel substrate. It was possible to fabricate TiO2 coatings with anatase phase and dense microstructure. The deposition efficiency was increased with gas temperature. The photocatalytic property of the coatings was evaluated by NOx elimination test. From the results, it became clear that cold sprayed TiO2 coatings had excellent photocatalyst property.
Influence of Powder Porous Structure on the Deposition Behavior of Cold-Sprayed WC-12Co Coatings
Authors: Gao P.-H. , Li Y.-G. , Li C.-J. , Yang G.-J. , Li C.-X. 
Published: September 2022

Abstract
The carbide decomposition and the dissolution of carbide into the binder accompanying with thermal spraying of cermets can be eliminated during cold spray deposition of WC-Co. However, the limited deformation of hard impacting cermet particles and impacted coating makes it difficult for conventional thermal spray powders to continuously build up on impact in cold spraying. The porous structure of WC-Co powders provides the powder particles with certain deformability on high velocity impact, which benefits the continuous building-up of coating. In this study, three nano-structured WC-12Co powders with different porous structures and apparent hardness were employed to deposit WC-Co coatings on stainless steel substrate by cold spraying. The deposition characteristics of three powders of different porosity levels of 44%, 30% and 5% were investigated. It was found that WC-Co coating is easily built-up using the porous powders with WC particles bonded loosely and a low hardness. The microhardness of WC-12Co coatings varied from Hv400 to Hv1790 with powders and spray conditions, which depends on the densification effects by impacting particles. With porous WC-Co powders, the fracture of particles on impact may occur and low deposition efficiency during cold spraying. The successful coating building up at high deposition efficiency depends on the design of powder porous structure.
Formation of NiTi Intermetallics by Heat Treatment of Cold-Sprayed Precursor Coating
Authors: Wang H.-T. , Li C.-J. , Yang G.-J. , Li C.-X. , Gao P.-H. , Zhang Q. 
Published: September 2022

Abstract
Nickel titanium is promising cavitation erosion resistant material. Using NiTi in bulk for components might not be feasible due to its poor workability, as well as the high material and processing costs. Surfacing components with its coating is effective for utilizing the good erosion properties of NiTi intermetallic compounds. In this study, a method to prepare NiTi intermetallic compound coatings in-situ through annealing of the cold-sprayed Ni(Ti) metastable coating was investigated. A nanostructured Ni(Ti) solid solution alloy powder was prepared by ball-milling process. The cold sprayed Ni(Ti) alloy coating was used as the precursor coating. The effect of annealing temperature on the microstructure in-situ evolution of Ni-Ti intermetallic compound in cold-sprayed coating was investigated. The morphology and phase composition of the powders milled for different durations and the microstructure of the as-sprayed coating were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that after annealing at 950°C the Ni(Ti) alloy was transformed to intermetallic phases. NiTi, Ni3Ti and NiTi2 intermetallic phases coexisted in the annealed coating.
Effect of Substrate Roughness on the Deposition Behavior of Kinetic Sprayed Copper Particles on Copper Substrate
Authors: Kumar S. , Bae G. , Yoon S. , Kim J. , Lee C. 
Published: September 2022

Abstract
In this work, effect of substrate roughness on the deposition behavior of the particles through kinetic spray technology is studied. Finite element analysis program, ABAQUS 6.7-2 was used to estimate the results. Particle impact on the planar and roughened substrates were analyzed and compared. Interface temperature, contact area and contact time were found to be higher for the particle impact on roughened surfaces than that of the planar one for constant spray condition. These factors are significant for bonding mechanism. Experiments were performed on the polished and grit blasted surfaces in order to compare the results. The deposition efficiency and the bond strength values were used to evaluate the effect of surface roughness.
Impact Behavior Characterization of Engineering Metals in Kinetic Spraying
Authors: Bae G. , Kumar S. , Yoon S. , Kang K. , Lee C. 
Published: September 2022

Abstract
In this study, three kinds of engineering metals, which are aluminum (1100-H12), commercially pure titanium and mild steel were combined as particle/substrate and classified into four cases, i.e., soft/soft, hard/hard, hard/soft and soft/hard, according to their physical and mechanical properties respectively. Based on finite element modeling, impacting interface elements of four cases were analyzed and impact behaviors were numerically characterized. For soft/soft and hard/hard cases, the maximum temperature at the substrate side, which approached melting point, is higher than that of particle side when the shear instabilities occur. In particular, the different size of thermal boost-up zone was numerically estimated and theoretically discussed for these two cases. Meanwhile, for soft/hard and hard/soft cases, the specific aspect of shear instability, which has very high heat-up rate, was always observed at the relatively soft impact counterpart, and a thin molten layer was expected as well. Thus, the successful bonding of the above mentioned four cases can be predicted as a result of the synergistic effect of localized shear instability with interfacial melting.
A Combined Process: Cold Spraying of Heterogeneous Coatings Followed with their High Energy Treatment
Authors: Solonenko O. , Kosarev V. , Golovin A. , Neronov V. , Korchagin M. , Poluboyarov V. 
Published: September 2022

Abstract
Presently, the self-propagating high-temperature synthesis (SHS) has found wide use in the production of compacts and powder materials, and also in the fabrication of end products. Yet, a disadvantageous feature of the standard SHS process, which can be overcome in part by running the synthesis reaction under pressure, is that it fails to provide the possibility of obtaining high-density materials and products. It is therefore of interest to develop a combined process which would allow one to apply a two-component Ni-Al coating with prescribed stoichiometric composition by cold spraying of a nickel-aluminum powder mixture followed by self-propagating high-temperature synthesis of a target intermetallide (Ni3Al or NiAl) by treating the surface layer of the cold sprayed coating with a highly-concentrated energy flux (argon plasma jet). Preparation methods for nickel-aluminum powder mixtures (in particular, mechanochemical activation) intended for cold spraying process are discussed. Computational experiments were performed to substantiate the choice of stationary, traveling and pulsed energy sources for subsequent initiation of SHS in the heterogeneous layer deposited onto a steel substrate. A model was developed to predict the local phase state of the material synthesized in the coating; this model involves the state diagram of the Ni-Al system. The characteristics of sprayed coatings were examined. The developed approach is shown to offer much potential in practical applications.
A Side-by-Side Comparison of Particle Temperature (Tp), Particle Velocity (Vp) Data Collected using the Accura G3 and the DPV-2000
Authors: Hall A. , Williamson R. , Urrea D. , Mccloskey J. , Beatty D. , Roemer T. , Hirschfield D. 
Published: September 2022

Abstract
A Sulzer-Metco 6P Powder Flame Spray Torch spraying an alumina-titania ceramic powder RX60 6-axis robotic was characterized using an Accura G3(Tecnar Automation; Quebec, Canada) and a DPV-2000 (Tecnar Automation; Quebec, Canada). The two sensors were mounted side-by-side and a robot was used position the torch in relation to each sensor. Process gas flows were set using laminar flow element mass flow controllers. Accura and DPV measurements of particle temperature (Tp) and particle velocity (Vp) were made in succession at each operating condition without changing torch operating conditions. Data for a single designed experiment was collected with both sensors allowing for comparison of the two sensors across the operating space of a typical powder flame spray process.
Asymmetric Melting Behaviour in Twine Wire Arc Spraying with Cored Wires
Authors: Tillmann W. , Abdulgader M. , Vogli E. 
Published: September 2022

Abstract
Asymmetric melting behaviour of the electrodes is a process related feature of the twin wire arc spraying (TWAS) technique since the heating of the negative connected wire is different from that of the positive connected wire. Due to these differences in melting behaviour a tracking of particle velocity and temperature for both electrodes individually is very important. Particle velocity and temperature have been recorded from anode and cathode by positioning the tracking device on each side of the spraying gun. To draw the whole picture of the spraying jet particles have been tracked also from the top side of the spray gun. The goal of this study is to have an experimental data set-up for model building and simulation of depositing process in TWAS. Corresponding measuring devices have been employed to investigate the TWAS process by spraying of massive and cored wires.
Gas Flow Drift Velocity Measurement on Plasma Spray Torches
Authors: Lange S. , Forster G. , Schein J. 
Published: September 2022

Abstract
In thermal spray processes fast gas flows are used to accelerate and melt the coating compound materials. The kinetic energy transferred to the particles by the gas flow depends on the velocity of the jet, which thus becomes an important parameter for coating formation. This paper describes a non-contact technique for measuring the drift velocity in those flows. This technique is based on the additional wavelength shift induced by the gas flow for non resonant light scattering. This shift of the order 1 pm is detected by an interferometer composed of two mechanical tilted plates, such that the wavelength of the scattered light can be easily obtained from the location of the maxima in the corresponding Airy profile paired with an MCP-CCD camera, to enhance sensitivity and processing speed. The experimental setup will be described and first results shown.
Flame-Spray Parameter Optimization to Manufacture Glaze Coatings Onto Thermally Sensitive Substrates
Authors: Arcondéguy A. , Montavon G. , Denoirjean A. , Pateyron B. , Grimaud A. , Gasgnier G. , Huguet C. , Planche M.P. 
Published: September 2022

Abstract
Glazes are attractive materials as they can be applied onto metallic or ceramic substrates to confer on them specific properties. They find numerous applications, from art ornamenting to protection against corrosion. Conventional process (vitreous glazing) requires a high temperature treatment (up to 1400 °C in some cases) to fuse glazes after their application on the surface to be covered. This treatment cannot be hence applied onto heat-sensitive substrates without severe degradation. Previous studies showed that manufacturing glaze layers by flame spraying prevents the substrate from thermal degradation. The coating formation mechanisms are different from the ones encountered with crystallized ceramic materials: the high surface tension of glazes prevents the particles from being totally spread (i.e., "dewetting" phenomena). Effects of glaze powder characteristics (chemical composition, particles morphology) on coatings structures were also studied. Furthermore, chemical analyses proved that flame spraying did not modify glaze compositions. The most adapted powder to flame spraying has been hence selected. This contribution describes the coating formation mechanism and discusses the influence of the feedstock powder physical properties on coating characteristics. It also estimates effects of spraying parameters on coatings morphology.
Wear Behaviors of HVAF Sprayed Nano WC-Co Coating Against Al-Ni-Bronze Alloy
Authors: Deng C.M. , Zhou K.S. , Liu M. , Deng C.G. , Hong R.J. 
Published: September 2022

Abstract
High velocity oxygen fuel (HVOF) sprayed WC coatings have been found wide applications as substitutions of chrome plating in the airplane industry. The wear of HVOF WC coated landing gear against Al-Ni-Bronze alloy leads to the wear or spalling of WC particles, and finally results in the degradation of sealing property for landing gear system. WC-Co coating with nano-size WC particles is expected to exhibit good wear resistance, and the weight loss of Al-Ni-Bronze alloy can also be reduced, which is beneficial to the sealing property of landing gear system. Three types of coatings are prepared using agglomerated, sintered nano-scaled WC-12Co, conventional WC- 12Co and WC-10Co4C powders, respectively. The wear behaviors of the as-sprayed coatings against Al-Ni- Bronze alloy are investigated at the different loads and linear velocities. The study is expected to provide the basis for the application of HVO/AF nano-scaled WC coating in landing gear.
High Velocity Oxy-Fuel (HVOF) Suspension Spraying of Mullite Coatings
Authors: Oberste Berghaus J. , Marple B.R. 
Published: September 2022

Abstract
Mullite coatings (3Al2O3 ·2SiO2) were deposited by suspension thermal spraying of micron-sized (D50 = 1.8 µm) feedstock powders, using a high-velocity-oxy-fuel gun (HVOF) operated on propylene (DJ-2700) and hydrogen fuels (DJ-2600). The liquid carrier employed in this approach allows for controlled injection of much finer particles than in conventional thermal spraying, leading to coatings with low porosity and fine and homogeneous porosity distribution, making this process potentially suitable for creating thin layers with low gas permeability. In-flight particle states were measured for a number of spray conditions of varying fuel-to-oxygen ratios and standoff distances and related to the resulting microstructure, stoichiometry, phase composition (EDS, SEM, XRD) and hardness (VHN 300gf) of the coatings. In an attempt to retain the crystalline phase in the coatings, HVOF operating conditions were varied to limit in-flight particle melting. However, fully crystalline coatings were only obtained by gradually heating the coating during deposition to temperatures above 400°C.
Role of HVOF-Spray NiCr Coatings to Control High Temperature Oxidation of Some Boiler Steels
Authors: Kaushal G. , Singh H. , Prakash S. 
Published: September 2022

Abstract
A study was carried out to determine the role of HVOF-spray Ni-20Cr coatings to enhance high temperature oxidation resistance of T22 and 347H boiler steels. Ni-20Cr coatings were deposited on the boiler steels. Subsequently high temperature oxidation behavior of these coatings was investigated by laboratory tests at an elevated temperature of 9000C under cyclic conditions. These coatings were also subjected to a boiler environment at an elevated temperature of 700ºC under cyclic conditions to ascertain their erosion-corrosion behaviour. Thermogravimetric data was taken after each cycle to formulate the oxidation, as well as, erosion-corrosion kinetics. The specimens were also physically examined after each cycle to notice any macrographic physical changes, spallation tendency of their oxide scales etc. The exposed specimens were examined using scanning electron microscopy and Energy Dispersive Spectroscopy (SEM/EDS) analysis. It was observed that oxidation rate was subsequently low in the coated substrates as compare to uncoated steels. It was observed that Ni-20Cr coating on 347H boiler substrate showed the maximum oxidation resistance. Moreover, both the steels showed better resistance to erosion-corrosion in actual boiler conditions after the application of Ni-20Cr coating.
A Numerical Model for Combustion and Expansion in HVOF Flame Spraying
Authors: Dongmo E. , Gadow R. , Wenzelburger M. 
Published: September 2022

Abstract
Nano structured coatings applied by supersonic flame spray processes show a better bonding mechanism, superior hardness and better wear resistance compared to coatings with micron scale structure. However, handling and particle feeding of smaller scale (&lt; 20µm) spray powders is difficult due to their large surface area and easy agglomeration, but also health risks. Therefore, nano structured oxide ceramic powders are mixed with organic solvents in order to form liquid suspensions that are suitable to improve the particle feeding properties. Recent attempts to understand the momentum and heat transfer mechanisms between flame and particles in HVOF flame spraying led to measurement of the in-flight particle properties and computational modeling of the processes. In this work, modeling and simulation of the HVOF spraying process as a two phase model is applied in order to analyze thermal and mass flow processes for an optimization of the spray particle properties and the final properties of the coatings themselves. Simulation results are given for particle tracking during the spray process. Thereby, particle properties are sensitive to a large number of process parameters as well as the particle diameter. Numerical results are validated by experimental diagnosis of particle properties with the SprayWatch system and by the analysis of experimental coatings.
HVAF Coating Application in Steel-Making Process
Authors: Korobov Y. , Filippov M. 
Published: September 2022

Abstract
A significant group of steel-making process parts is exposed to high contact pressure, shock abrasive wear and elevated temperature. High productivity repair techniques are necessary because of the large size of the parts. Analysis of coating metallographic investigations, wear and corrosion test results, full-scale tests shows that restoration of base share of these parts is possible by High Velocity Oxygen Fuel / High Velocity Air Fuel (HVOF/HVAF) process. Comparison of manufacture's data has showed that HVAF excels HVOF alternatives noticeably at productivity. At the same time production costs are 2-2.5 times less. With regard to typical steel-making process parts some investigations results and examples of HVAF restoration at Joint Stock Company "Mashprom" are represented.
Properties of Long Persistent SrAl2O4 Ceramics Coating Deposited by Low Power Plasma Spraying
Authors: Zhou F. , Fu Y. , Gao Y. 
Published: September 2022

Abstract
Strontium aluminates activated by Eu, Dy3+ ions has recently attracted more attention due to not only their bright luminescence and super long afterglow without radioactivity but also the extensive application. SrAl2O4:Eu, Dy coatings were prepared by low power plasma thermal spraying (2.5-4W). The optimum spraying conditions have been established with spray parameters. The effects of the plasma conditions on the porosity rate of the coatings were investigated by many techniques, respectively X-ray diffraction (XRD) and scanning electron microscopy (SEM). To better qualify the characteristics of these coatings prepared from spray-dried powders, luminescence characteristics were also studied.
Comparative Study between Ar-H2 and N2-H2 Plasma Gas Mixtures: Application to ZrO2-Y2O3 Coatings
Authors: Noguès-Delbos E. , Goutier S. , Vardelle M. , Fauchais P. , Granger P. 
Published: September 2022

Abstract
In plasma spray process, ceramic coatings can be sprayed by using either argon-hydrogen or nitrogen-hydrogen plasma gas mixtures. Starting from a given particle size distribution the question is what are the spray parameters allowing achieving similar coatings with these types of plasmas? The problem is made more complex because a torch working with Ar-H2 is different from that using N2-H2 as plasma forming gas. It is thus necessary to compare the gas mixture properties, the torches working conditions (mean voltage and thermal efficiency for given current), the arc column diameter relatively to the nozzle internal diameter and the spray parameters, the arc root fluctuations, the powder injection, the particles mean temperatures and velocities as well as their fluctuations linked to those of arc root, the splat formation, the coating porosity and deposition efficiency. This comparison has been achieved for ZrO2-Y2O3 (7 vol%) powder with a size distribution between 5 and 25 µm and using the same plasma torch for the two plasma gas mixtures: a 3MB torch with a cylindrical anode nozzle and 5.5 mm in internal diameter.
Fluctuations in One-Cathode Plasma Torches: Characterization and Modelling
Authors: Marqués J.-L. , Fuchs M. , Dschung F. , Lange S. , Zierhut J. , Schein J. 
Published: September 2022

Abstract
Increasing erosion of the anode wall of a single-cathode F4 torch changes the fluctuation pattern of the plasma jet. Trajectories and temperature history of particles injected into the plasma become accordingly modified. In this work such fluctuations are characterised through spectral analysis of the torch voltage as well as of the light intensity of the jet outside the torch. Instead of considering the evolution of the main peaks in the frequency spectrum for both voltage and optical signals, the variation with increasing torch wear of the spectrum’s higher frequency fraction (above 20kHz) is focused on. The evolution of the fractal dimension in this high frequency range exhibits a reliable correlation with the erosion of the anode wall. This is confirmed further by the development of a simple stochastic model for the motion of the arc root along the anode wall. This model yields, depending on the probability for a pronounced arc root jump, a fractal dimension and an evolution just within the range observed in the measurements. Additionally, tracking the fluctuations at different locations outside the torch enables the isolation of the fluctuation dissipation due to jet viscosity and velocity.