bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Powder Size on the Structures and Properties of the Cold Sprayed Copper Coatings
Authors: Sakaki K. , Shinkai S. , Shimizu Y. 
Published: August 2022

Abstract
Powder size, which influence on spray particle behavior in super sonic gas flow in and out of nozzle, is one of the most important parameters in cold spray process. In the other hands, it was reported that small particles (smaller than 5ƒÊm in diameter) decelerate significantly close to the substrate by the bow shock in cold spray. In this study, numerical simulation and experiments investigated the effect of the powder size of copper on the cold spray process and the structures and properties of the cold sprayed coatings. In the numerical simulation, it is assumed that gas flow within the nozzle is quasi-one-dimensional isentropic flow of semi-perfect gas. A spray powder of copper is used. Mean diameter of copper powder 1, 5, 10, 15 @and 45ƒÊm are used. Working gas (is nitrogen) pressure and temperature at nozzle-intake are 3MPa and 350 ‹C. With decreasing particle diameter, calculated particle velocity at the nozzle exit increase immediately. So deposition efficiency increase immediately with decreasing particle diameter until 5ƒÊm. Abstract only; no full-text paper available.
Effect of Particle Geometry and Substrate Preparation in Cold Spray
Authors: Richer P. , Jodoin B. , Taylor K. , Sansoucy E. , Johnson M. , Ajdelsztajn L. 
Published: August 2022

Abstract
Cold Gas Dynamic Spraying is a relatively new high rate deposition process that uses a supersonic gas flow to accelerate fine powder particles (micron size) above a critical velocity. Upon impact, the particles deform plastically and bond to the substrate to form a coating. In this study, nanocrystalline Al-Mg coatings are produced using the Cold Spray technology. In an attempt to improve the understanding and optimize the process, the effects of substrate preparation and substrates thickness on the overall quality of the coatings are investigated. Two different grit materials are used to prepare the substrates with simple grit-blasting. Results show that the use of different grit sizes leads to changes in the mass deposited on the substrate (deposition efficiency) but has no significant effect on the coating microstructure. Other trials are conducted on samples of different thickness to verify the applicability of the Cold Spray process on thin surfaces. Results show that the Cold Spray process can be used to produce coatings on thin surfaces without noticeable damage to the substrate and with the same coating quality.
Spray Forming Titanium Alloys using the Cold Spray Process
Authors: Blose R.E. 
Published: August 2022

Abstract
Development of new, low-cost methods for spraying near net shapes of Titanium and Titanium alloys is critical for many industries and applications. Direct fabrication technologies would have an impact on many industries because of the potential to quickly manufacture complex parts or additive features with minimal waste. However, currently used high temperature spray technologies (Lasform, thermal spray methods) involve melting and solidification. Each new layer starts out molten, then solidifies, and must eventually cool to room temperature. This report presents results of feasibility tests for development of a new method of direct fabrication of Ti alloy parts at near-net shapes (nns) using the Cold Spray process (CSP). Several Ti-6Al-4V powders including gas atomized, plasma atomized, and hydride dehydride were tested in these experiments. Feedstock powders were characterized for particle size distribution, morphology, chemical composition, hardness, and deposition efficiency. Coatings in thicknesses of 2 mm were sprayed for evaluation of microstructure, hardness, and porosity. Thick rectangular prisms (10 mm) were sprayed for machining tensile specimens. The material properties of as sprayed and post treated coatings by heat-treating and hot isostatic pressing (HIPing) on material properties was studied. Analysis showed that after HIPing the density of sprayed Ti-6Al-4V coupons is near 100% and material properties met or exceed those of wrought material.
Cold Spray Nozzle Design and Performance Evaluation using Particle Image Velocimetry (PIV)
Authors: Pattison J. , Morgan R. , Celotto S. , Khan A. , O'Neill B. 
Published: August 2022

Abstract
Based on the principles of cold spray, Cold Gas Dynamic Manufacturing (CGDM) is a high-velocity metal spraying process capable of the high-rate deposition of dissimilar materials under cold conditions. However, unlike many cold-spraying techniques that have focussed primarily on surface coatings, the CGDM process has been tailored for solid free-form fabrication. Central to the needs of the process is the ability to accelerate the feedstock powder – through entrainment into a high-velocity gas flow – to speeds in excess of its critical deposition velocity. The critical factor here is not the gas velocity but rather the ultimate particle velocity; and it is the drag force experienced by the individual powder particles that affect their velocity. This paper documents the methods used to predict, model and validate nozzle performance – in terms of particle acceleration and ultimate velocity – via Computational Fluid Dynamics (CFD) and Particle Image Velocimetry (PIV). Results are presented and discussed pertaining to the effects of nozzle type (de Laval, MLN etc.) and geometry, as well as gas type (Helium and Nitrogen), composition and temperature. Abstract only; no full-text paper available.
The Effect of a Simple Annealing Heat Treatement on the Mechanical Properties of Cold-Sprayed Aluminium
Authors: Hall A.C. , Cook D.J. , Neiser R.A. , Roemer T.J. , Hirschfeld D.A. 
Published: August 2022

Abstract
Cold spray, a new member of the thermal spray process family, can be used to prepare dense, thick metal coatings. It has tremendous potential as a spray forming process. However, it is well known that significant cold work occurs during the cold spray deposition process. This cold work results in hard coatings but relatively brittle bulk deposits. We have investigated the mechanical properties of cold sprayed aluminum and the effect of annealing on those properties. Cold spray coatings approximately one centimeter thick were prepared using three different feedstock powders: Valimet H-10, Valimet H-20, and Broadman Flomaster. ASTM E8 tensile specimens were machined from these coatings and tested using standard tensile testing procedures. Each material was tested in two conditions: as-sprayed and after a 300°C, 22 h air anneal. The as-sprayed material showed high ultimate strength and low ductility, &lt; 1% elongation. The annealed samples showed a reduction in ultimate strength but a dramatic increase in ductility, up to 10% elongation. The annealed samples exhibited mechanical properties similar to wrought 1100 H14 aluminum. Microstructural examination and fractography clearly showed a change in fracture mechanism between the as-sprayed and annealed material. These results indicate good potential for cold spray as a bulk forming process.
Finite Elements Modelling of Transient Thermal Stresses Developed in Ceramic Coatings During Thermal Cycling Conditions
Authors: Robin P.C. , Gitzhofer F. , Boulos M.I. , Fauchais P.L. , Hogge M. 
Published: August 2022

Abstract
Ceramic functional coatings are frequently applied to structure materials in a wide range of mechanical and chemical applications for their specific properties of hardness, passive resistance to chemical aggression and low thermal conductivity. The counter part of those specific properties is a low mechanical and thermal shock resistance. Thus it is of prime importance to investigate the fundamental mechanisms, which governs the failure under thermal shock and thermal cycle conditions to increase the range of reliable industrial applications. The work presented in this paper deals with the Finite Element Modelling [FEM] of the transient thermal fields and associated stresses developed in ceramic coatings during firstly the post deposition cooling step and secondly during thermal cycling conditions. Alumina [Al2O3] and Partially Stabilized Zirconia [PSZ] coatings, which are both widely used in mechanical and chemical industries, are under investigation.
Numerical Analysis of Injection Diesel Spray Using Modified KIVA Code and Comparison to Experimental Works
Authors: Rezaei R. , Raisee M. , Mirsalim S.M. , Bahmanpour D. 
Published: August 2022

Abstract
In the last decade 3D-CFD has been successfully established for three-dimensional simulations of fluid flow, mixture formation, combustion and pollutant formation in internal combustion engines. In direct injected engines, the accuracy of simulation results and hence their contribution to design analysis and optimization strongly depends on the predictive capabilities of the models adopted for simulation of the injector flow, spray formation and propagation characteristics. The original KIVA-3V code uses the droplet collision algorithm of O’Rouke for calculating collisions in Lagrangian spray simulation. The modified KIVA-3V code includes no-time-counter (NTC) method which is proposed by David P. Schmidt (2000). The NTC method of calculating spray droplet collisions is both faster and more accurate than the current standard method of O’Rouke. In this work an original and a modified version of KIVA-3V multi-dimensional CFD code is used to simulate the spray resulting from the injection of diesel fuel. Numerical results from original and modified KIVA-3V are compared to experimental data and also results obtained from Fire code.
Modeling of Temperature and Residual Stress Fields Resulting from Impacting Process of a Molten Ni Particle Onto a Flat Substrate
Authors: Fan Q. , Wang L. , Wang F. , Wang Q. 
Published: August 2022

Abstract
Several effective numerical techniques, based on finite element analysis, have been developed and computed independently in this paper. Results are presented describing the impacting process, and the subsequent temperature and residual stress fields of a molten nickel particle impacting onto a flat substrate. Problems of this type, especially the prediction of the thermal residual stresses, are of major practical interest in thermal spray operations as a pioneering approach.
Modeling of Non-Equilibrium Supersonic Plasma Jets at Low Pressure
Authors: Blais A. , Jodoin B. 
Published: August 2022

Abstract
Low Pressure Plasma Spraying (LPPS) is a spraying technique developed in the 1970s that uses a converging-diverging nozzle (i.e. de Laval nozzle) inside a controlled atmosphere chamber. With such a set-up, it is possible to obtain a plasma jet in the supersonic flow regime, which may encounter several non-equilibrium phenomena. First, the operating pressures (i.e. chamber and torch exit) determine the aerodynamic state of the supersonic plasma jet. Operating at the nozzle design pressure insures aerodynamic equilibrium of the plasma jet while other chamber pressure brings a state of “aerodynamic non-equilibrium” for which expansion, compression and shock waves appear. Second, a low chamber pressure corresponds to a decrease in the number of collisions between electrons and heavy species (i.e. atoms and ions). This rarefaction of the plasma causes a state of “thermal non-equilibrium” for which there exist two different temperature distributions, Te and Th, respectively representing the electrons and the heavy species. Third, the high velocity of the plasma jet can bring a state of “chemical non-equilibrium” as the hydrodynamic time scale of the flow might become smaller than its chemical time scale. Hence it is a challenging task to model a phenomenon as complex as the low pressure supersonic plasma jet. The model developed in this work uses a commercial code in which recent advances in the field of plasma transport properties are implemented. It considers chemical non-equilibrium through the solution of the electrons conservation equation while the two temperature distributions each require the solution of an energy balance. The validation of the model is possible from recent measurements with a new method enhancing the capabilities of the enthalpy probe technique to supersonic jets in aerodynamic non-equilibrium. Abstract only; no full-text paper available.
Effect of the Surface Adsorbates on the Morphology of Plasma-Sprayed Splats
Authors: Li C.-J. 
Published: August 2022

Abstract
Copper splats are deposited on the flat stainless steel surface at the ambient and preheated conditions. The splashing occurs as the splats are deposited at an ambient atmosphere. The characteristics of the splashing occurring at different splat regions during spreading of the droplet are examined. The splashing can be classified into two types according to the splashing mechanisms. At the surrounding region of the splat larger than flattening ratio about 1.5 to 2, the radial splashing takes place by jetting-away of splat materials, which leads to the formation of a splat with a reduced diameter. At the central area of the reduced splat, the upward splashing occurs through the blowing up of the top surface layer which results from the high pressure of gas bubbles. At the preheated condition which can remove surface adsorbates, no evident splashing occurs under the normal spray conditions. Two types of splashing can be explained by the gases evolved through evaporation of the adsorbates resulting from the heating of the high temperature droplet. The spreading of the droplet involved in the wave urging flow is presented.
Influence of Powder Size Distribution and Heat Flux on Yttria Stabilised Coatings Elaborated by Liquid Suspension Injection in a DC Plasma Jet
Authors: Delbos C. , Fazilleau J. , Rat V. , Coudert J.F. , Fauchais P. , Bianchi L. 
Published: August 2022

Abstract
This paper is devoted to the study of coatings elaborated by a process permitting Air Plasma Spraying (A.P.S.) of finely structured ceramic coatings. This process mainly consists in injecting in a d.c. plasma jet, a ceramic suspension containing sub-micron ceramic particles. Coating characteristics are close to those observed in P.E.C.V.D., but with a faster elaboration rate (. 15 µm/m2.h) and, the possibility to produce a wide range of thicknesses (1 &lt; e &lt; 100 µm). This paper is aimed at producing the Yttria Stabilized Zirconia electrolyte (Y.S.Z.) of Solid Oxide Fuel Cells with a thickness of 5 to 30 µm. Previous studies of this process have been devoted to the influence of the spray parameters on the structure of Y.S.Z. splats collected and have allowed determining some well adapted working conditions. The new stage described in this paper, is related to the study of the growth of Yttria Stabilized Zirconia coatings and the influence of different parameters such as the ceramic particle size distributions contained in the suspension and the heat flux imposed to the surface of the substrate and successive passes during the coating elaboration.
Influence of the Voltage Modulation Frequency on Voltage Trace and Wire Arc Coatings Properties
Authors: Wilden J. , Bergmann J.P. , Jahn S. , Zimmermann S. 
Published: August 2022

Abstract
Due to the low running costs, high spray rates and efficiency wire arc spraying has become one of the most important thermal spray technology, especially as a tool for coating large areas with high deposition rates. The main applications are corrosion and wear protection of large structures, such as coating with zinc for anodic corrosion protection or with high-alloyed chromium steel for longer surface service time. Disadvantages of the arc spraying process are on the one hand that only electrically conductive materials can be processed and on the other hand the higher oxygen content within the coating compared to other thermal spray processes such as HVOF or APS. Innovative and flexible power supply systems were developed for arc welding technologies in the last decade. Today power supply devices with new features for arc wire spraying technologies are present at the market, too. Particle flow conditions as well as coating properties such as morphology and oxide content can be optimized by changing the current generator characteristic and modulating the energy input for example by pulsing the spray voltage up to 500 Hz. As a consequence of the power modulation the oxidation of the particles can be reduced by a lower heat input based on lower average spray voltage. Investigations in order to influence the droplet behaviour and the coating microstructure using dynamic current generators were performed for zinc, aluminium and copper. The effect of different modulation frequencies, pulse lengths and pulse voltages are presented.
Production of Samarium Doped-Ceria Plasma Sprayed Nano-Coatings Using an Internal Injection of a Suspension Containing Nanoparticles
Authors: Bouaricha S. , Oberste-Berghaus J. , Legoux J.-G. , Moreau C. , Ghosh D. 
Published: August 2022

Abstract
For solid fuel cell application, thin electrolyte is needed for novel materials that allow reducing their operating temperature. The influence of what called ‘the thermal management of the coating and the substrate’ is discussed. In particular, influence of substrate temperature and the nature of the substrate. It was found that adequate control of the coating and substrate temperature, together with an equivalent substrate/coating thermal expansion coefficients (CTE) are the key-factor to successfully obtain an SDC nanosized thin and dense coating free of cracks.
Deposition and Crystallization of Thermally Sprayed Amorphous Metallic Coatings
Authors: Rohan P. , Bouaricha S. , Legoux J.-G. , Moreau C. , Denoirjean A. , Vardelle A. , Le Niniven C. 
Published: August 2022

Abstract
The high cooling rate (&gt;105 - 106 K/s) achieved in thermal spraying makes it possible to deposit coatings that exhibit a high content of amorphous phase and can be, afterwards, heated above the crystallization temperature to form nano-structured coatings. In this study, the relationship between the characteristics (temperature and velocity) of the sprayed particles at impact and degree of amorphization of the as-sprayed coatings was investigated for both plasma and wire-arc spraying techniques A Fe-Cr-based alloy that exhibits a high glass forming ability and is commercially available in the form of powder and wire with close chemical composition was used. The amorphous phase content was higher in plasma sprayed coatings than in wire arc sprayed ones and both types of coatings presented an increase in microhardness after heat treatment.
Plasma Spraying Behaviour and Properties of Aynthesized/Agglomerated Calcium/Magnesium Zirconates versus Lime/Magnesia Stabilized Zirconia
Authors: Písačka J. , Neufuss K. , Dubský J. , Kolman B. , Nohava J. 
Published: August 2022

Abstract
Calcium zirconate and magnesium zirconate prepared by synthesis and agglomeration were sprayed using a water stabilized plasma gun under varied spraying conditions. The same set of conditions was maintained during spraying of fused lime stabilized zirconia and magnesia stabilized zirconia. The intent of the study was to compare spraying behaviour and deposit properties of pairs of feedstock material that have just about the same chemical composition but differ considerably in the way of preparation. Free-flight particles as well as deposits were characterised by standard techniques, such as light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, differential thermal analysis, and pycnometry. The differences between relevant coatings were evaluated namely in terms of morphology, chemical and phase composition, density and porosity. Sources of observed differences are discussed.
Simultaneous Deposition of LSM and YSZ for SOFC Cathode Functional Layers by an APS Process
Authors: Hathiramani D. , Mobeen A. , Fischer W. , Lersch P. , Sebold D. , Vaßen R. , Stöver D. , Damani R.J. 
Published: August 2022

Abstract
In order to reduce the manufacturing costs of SOFC layer systems the atmospheric plasma-spray (APS) process is an attractive technique. Especially the deposition of high performance cathodes, which are essential for a high power density of the SOFC, are of major importance. The cathode functional layer (CFL) has to provide a high amount of triple-phases boundaries to allow the cathodic oxidation reaction. A typical materials mixture used for such a CFL is the perovskite (La0.65,Sr0.3)MnO3 (LSM) and the fully Y2O3-stabilized zirconia (YSZ). A sufficiently porous layer has to be formed where both components are mixed on a sub-micrometer scale. In addition to the tough challenge concerning the creation of a suitable microstructure of a CFL deposited by an APS process two additional difficulties have to be solved: i.) a decomposition of the perovskite and ii.) a chemical reaction between the LSM and the YSZ during the atmospheric plasma-spray process must be avoided. Suitable spray processing strategies were developed to overcome these problems. Cathode functional layers were produced by an atmospheric plasma-spray process using a multi-cathode Triplex-APS torch. Coatings are characterized by SEM, EDX, XRD and the porosity was determined by digital image analysis. SOFC layer systems with the new developed CFL are tested in single fuel cell tests.
Microstructures of Sprayed SiCp/Al Composites
Authors: Hu M. , Kang S. , Euh K. 
Published: August 2022

Abstract
The SiCp/Al composite was fabricated by a plasma spraying technique. By mean of OM SEM, TEM, XRD, SAED, EDS techniques, the microstructures for sprayed SiCp/Al composite were investigated in detail. The composite consisted of SiC and Al, along with single crystal Si and amorphorous Si, and tiny Al2O3. On the whole, the interfaces between SiC particle and Al bonded well, and tiny reactants like Al2O3 can be found near the interfaces. The mechanisms of chemical reactions were given during spraying. The nano-Al grains and nano-Al particles were seen in the sprayed composite. The formation mechanism of nano-Al grains and particles of SiCp/ Al composite was explained. Some interface relationships existed in the sprayed composite.
Cytocompatibility of Plasma Sprayed Bioceramic Coatings
Authors: Liu X. , Ding C. 
Published: August 2022

Abstract
In this paper, the Al2O3, ZrO2, TiO2, wollastonite, dicalcium silicate and their composite coatings were deposited onto Ti-6Al-4V substrates by an atmosphere plasma spray system. The rat osteoblasts were seeded onto the surface of the coatings to evaluate the growth behavior of osteoblasts on different implant materials. Scanning electron microscopy was used to observe the morphologies of the osteoblasts seeded on the surface of the coating for different time. The SEM observation indicated the osteoblasts are difficult to survive and proliferate on the Al2O3 coating surface. Osteoblasts can survive and proliferate slowly on the TiO2 and ZrO2 coating surface. Osteoblasts grow and proliferate very well on the surface of the wollastonite and dicalcium silicate coating, which present the two coatings possess excellent cytocompatibility. The addition of wollastonite and dicalcium silicate into ZrO2 and TiO2 can improve their cytocompatibility.