bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of Reactive Spray Atomization and Deposition
Authors: Dai S. , Delplanque J.-P. , Lavernia E.J. , Rangel R.H. 
Published: May 2021

Abstract
Recent experimental investigations of reactive spray deposition of aluminum alloys have indicated that oxides could not be detected for atomization gas oxygen contents lower than 10%. In order to elucidate this behavior, an analysis of the oxidation kinetics during reactive spray deposition based on the Mott-Cabrera theory of oxidation is proposed herein. A linear growth law is obtained that indicates that the oxide growth rate decreases with decreasing temperature or oxygen pressure. Furthermore, the oxide growth rate is found to decrease faster at low oxygen pressure with decreasing temperature as well as at low temperature with decreasing oxygen pressure. Calculations of the width of oxide stringers as a function of oxygen content and superheat temperature based on this analysis are in good agreement with the experimental observations.
Modeling and Diagnostics of the Praxair HVAF Combustion Spray Process
Authors: Varacalle D.J. , Irons G. , Lalumiere R.J. , Swank W.D. , Lagerquist J. 
Published: May 2021

Abstract
The high-velocity air-fuel process (HVAF) is an emerging technology used in the thermal spray industry. The Praxair HVAF process combines air and a liquid fuel (e.g., kerosene, diesel) to generate an energy source with extremely high gas velocities. Analytical studies were conducted to investigate gas and particle dynamics in the Praxair HVAF process for coating with WC-l2Co and stainless steel powders. The mass, momentum, and energy conservation equations were first solved, using the TORCH computer program. Typical output from the model includes temperature and velocity profiles as a function of radial and axial position. The PROCESS gas/particle computer program was then used to calculate from these temperature and velocity profiles the dynamics of particles injected into the gas plume. The primary result of the gas/particle code is a description of the injected particle temperature and velocity as a function of position in the plume. A thorough understanding of the process was obtained using this modeling technique. The results of the modeling were confirmed with process diagnostics. Particle temperature measurements for the WC-Co powder system were obtained with a two-color pyrometer; particle velocity measurements were obtained using particle imaging velocimetry. The coatings produced in the study exhibit superior quality, with high-density, high-hardness, low-oxide content, and high-bond strength.
Finite Elements Modeling of Liquid Particle Impacting onto Flat Substrates
Authors: Feng Z.G. , Montavon G. , Coddet C. , Feng Z.Q. , Domaszewski M. 
Published: May 2021

Abstract
The deformation and spreading of fully molten particles impacting onto a rough surface have been investigated by numerical simulation. A numerical technique, based on finite element analysis, was developed specifically for this simulation. The Lagrangian method with an automatic remeshing technique has been used to trace accurately the free surface of the molten matter and to improve the accuracy of the computation. A friction limiting condition at the particle substrate interface was introduced to describe the effects of the substrate surface roughness. This surface characteristic significantly influences the flattening degree, the flattening time, the spreading velocity of the liquid particle and its final shape.
Numerical Modeling and Simulation of Particle Behaviors in an HVOF Supersonic Flow
Authors: Yang Y.-M. , Coddet C. , Imbert M. 
Published: May 2021

Abstract
Dynamic and thermal behaviors of particles injected into an HVOF supersonic flow were modeled using the Lagrangian formulation coupled with a moving grid system which allows to treat melting and solidification problems in a particle. The particle behaviors of alumina, Tribaloy-400 and MCrAlY were examined by numerical simulations. Velocities calculated by this model were compared with experimental measurements available in publications. For investigating the particle temperatures for which experimental data are hardly available, qualitative experiments were conducted with an MCrAlY powder. It was thus observed that unmelted particles predicted by the numerical simulation were also found in the microstructure of the sprayed MCrAlY coating. From this work, it was shown that the established model provides a reasonable prediction of dynamic and thermal particle behaviors in HVOF flows.
The Features of the Modeling of High-Velocity Pulsating Jets
Authors: Potapenko A.N. , Konstantinov I.S. , El-Hammoudani A. , Semernin A.N. 
Published: May 2021

Abstract
By means of mathematical modelling the features of an outflow of high-velocity pulsating jets out of chambers of gas-detonation installations intended for handling materials are investigated. The boundary value problem is reduced to a solution of an inhomogeneous wave equation with allowance for pressure variation on the boundary of the pulsed source. The calculation of gas-dynamic fields of velocities and pressures is carried out, the volumetric density of potential and kinetic energies and its concentration on the surface under treatment are defined.
Influence of Mechanical and Thermal Behaviour of Stainless Steel Powder Particles During High Velocity Oxy-Fuel (HVOF) Spraying on Properties of Coatings
Authors: Sobolev V.V. , Guilemany J.M. , Martin A.J. 
Published: May 2021

Abstract
Influence of the in-flight behaviour of the stainless steel 316 powder particles during high velocity oxy-fuel (HVOF) spraying on the properties (porosity and level of oxidation) of the coating is studied. Modelling of the in-flight behaviour is undertaken which takes into account the combustion process, gas dynamics, gas-particle interactions, acceleration and deceleration of the gas flow, heat transfer in the particles and full thermal history of the particles including their melting, cooling and the possible solidification. The results obtained are used for the explanation of the experimental data on the coating porosity and level of oxidation.
Modeling and Diagnostics of a New High-Velocity Combustion Wire Spray Process
Authors: Varacalle D.J. , Irons G. , Lalumiere R.J. , Swank W.D. , Lagerquist J. 
Published: May 2021

Abstract
The High-Velocity Combustion Wire Process is a new high-velocity combustion process now being used in the thermal spray industry. This process combines air, oxygen, and a fuel gas to generate a high-temperature, high-velocity plume that is optimum for producing metallic coatings. Analytical studies were conducted to investigate gas and droplet dynamics for the spraying of three different materials: aluminum, stainless steel, and molybdenum. With the relatively low flame temperatures of the process, the feedstock wire is melted by convective heat transfer with no superheating or vaporization of the droplets. When the droplets strike the substrate, their temperature peaks as the high kinetic energy of the droplet is transformed into thermal energy. The conservation equations were solved using the TORCH computer model, yielding the temperature and velocity profiles as a function of location. The PROCESS gas/droplet computer program was then employed to calculate the dynamics of the molten droplets. The results of this modeling was confirmed with process diagnostics. Experimentation included droplet temperature measurements using a two-color pyrometer and droplet velocity measurements using particle imaging velocimetry for the stainless steel material system. The coatings produced in the study exhibit superior quality with high density, high hardness, low oxide content, and high bond strength.
Microstructure and Corrosion Behaviour of HVOF Sprayed Nickel-Based Amorphous/Nanocrystalline Alloys
Authors: Dent A.H. , Horlock A.J. , Harris S.J. , Mccartney D.G. 
Published: May 2021

Abstract
The corrosion characteristics of two bespoke Ni-Cr-Mo-B alloy powders sprayed by the high velocity oxy-fuel (HVOF) process have been studied using potentiodynamic and potentiostatic corrosion analysis in 0.5M H2SO4. The deposits have also been microstructurally characterised using X-ray diffraction (XRD), scanning electron microscopy (utilising both secondary electron (SE) and backscattered electron (BE) modes), and transmission electron microscopy (TEM). Results from the microstructural examination of the two alloys have revealed a predominantly amorphous/nanocrystalline (fcc) matrix containing submicron boride precipitates as well as regions of martensitically transformed laths. Apparent recrystallisation of the amorphous matrix has also been observed in the form of cellular crystals with an fcc structure. The oxide stringers observed at splat boundaries were found to be columnar grained α-Cr2O3, though regions of the spinel oxide NiCr2O4 with a globular morphology were also observed. The coatings of the two alloys exhibited comparable resistance to corrosion in 0.5M H2SO4, as revealed by potentiodynamic tests. They both had rest potentials approximately equal to -300mV(SCE) and passive region current densities of around 1mAcm-2. Microstructural examination of samples tested potentiostatically revealed the prevalence of degradation at splat boundaries, especially those where significant oxidation of the deposit had occurred.
Thermal Spray Quasicrystalline Coatings Part II: Relationships Among Processing, Phase Assemblage, and Tribological Response
Authors: De Palo S. , Usmani S. , Kishi K. , Sampath S. , Sordelet D.J. , Besser M.F. 
Published: May 2021

Abstract
Al-Cu-Fe quasicrystalline coatings, due to their high hardness and low friction coefficients, are potential candidates for improving the wear resistance of ductile materials. However, technological applications may be limited on account of their brittle nature. This study examines the effects of starting powder composition and thermal spray process parameters on the phase assemblage, microstructure, and tribological response of Al-Cu-Fe thermally sprayed coatings. It was found that the coatings fail by a delamination mechanism in unlubricated unidirectional sliding wear. Furthermore, the coatings produced by the high velocity oxy-fuel technique showed a very low coefficient of friction and wear rate.
In Situ Temperature Measurement Using Embedded Micro-Thermocouples in Vacuum Plasma Sprayed Multi-Layered Structures
Authors: Verdy C. , Serio B. , Coddet C. 
Published: May 2021

Abstract
The integration of thermocouples into thermal spray deposits and especially into vacuum thermal spray coatings could provide temperature monitoring between the substrate and the coating or between two different coatings during the spray process and later during post treatments and service life. Thermocouples of 251µm in diameter were made using Chromel and Alumel wires. Electrical insulation was obtained using a ceramic cement. Astroloy and Copper coatings were successfully sprayed over these sensors and the temperature given by an embedded thermocouple was compared to the response of an infrared pyrometer during the spraying process.
Investigations of the Fracture of Composites Matrix-Coating Under Tension
Authors: Panin V.E. , Klimenov V.A. , Panin S.V. 
Published: May 2021

Abstract
Deformation stages and specific features were studied by mesomechanical methods under tension of plasma sprayed coating-steel matrix composites. The effect of coating quality on the deformation of the matrix at the mesolevel was revealed. The results obtained make it possible to predict reliability and durability of this kind of coating and of the entire composite.
Residual Stresses during Coating Generation: Plasma Sprayed Alumina Coating on XC38—Measurements and Calculations
Authors: Leger A.C. , Haddadi A. , Pateyron B. , Delluc G. , Grimaud A. , Nardou F. , Fauchais P. 
Published: May 2021

Abstract
A simplified 1D model has been developed to calculate the temperature-time history of alumina layering splats. The splats were obtained by plasma spraying alumina fused-and-crushed particles onto steel substrates. The model correlates solidification time with splat layer thickness and cooling rate and helps to explain the process of columnar growth, the development of residual stresses, and the effect of quenching and expansion mismatch.
Coatings for Plasma-Facing Components of Nuclear Fusion Devices
Authors: Mallener W. , Rauwald K.H. , Duwe R. 
Published: May 2021

Abstract
Tungsten coatings on copper substrates were produced and subjected to thermal shock loads in an electron beam device. The aim was to minimize the erosion rates thus caused. They are basically dependent on the level and type of porosity. Moreover, material erosion can also be directly influenced by the spraying parameters in coatings with the same relative density. In this connection, the chamber pressure, powder size and spraying distance play a decisive role.
Plasma Sprayed Boron Carbide Coatings as First Wall Material for Laser Fusion Target Chamber
Authors: Bianchi L. , Brelivet P. , Freslon A. , Fornier A. , Cordillot C. , Jequier F. , Schirmann D. 
Published: May 2021

Abstract
The Laser Megajoule (LMJ) is designed to produce, in laboratory, fusion energy with a significant gain. Such an energy could be achieved by imploding a small capsule filled with a DT mixture. Fusion experiments produce a large emission of neutrons, x-rays, laser scattered light and debris which impose a first wall protection for the laser target chamber made of a low Z and refractory material. As boron carbide appeared to be a good candidate, among others, it was decided to evaluate the potentiality of plasma sprayed B4C coatings for this application. This paper deals with the optimization of plasma spraying conditions to build up coatings that satisfy specifications required for the first wall. Coating general properties are presented as well as outgassing performances. Specific x-ray and laser tests were performed to evaluate coating behavior close to real LMJ working conditions.
W and B4C Coatings for Nuclear Fusion Reactors
Authors: Cavasin A. , Brzezinski T. , Grenier S. , Smagorinski M. , Tsantrizos P. 
Published: May 2021

Abstract
The development of nuclear fusion reactors is presently considered to be the only possible answer to the world's increasing demand for energy, while respecting the environment. Nuclear fusion devices may be broadly divided into two main groups with distinctively different characteristics: magnetic confinement fusion (MCF) and inertial confinement fusion (ICF) reactors. Although the two nuclear fusion technologies show similarities in energy levels (as high as 3 J/cm2) and type of environment (high temperature plasmas) to be contained, the materials of choice for the protective shields (first wall in the ICF and deflectors in the MCF) differ significantly. In ICF reactors, multiple laser beams are used to ignite the fuel in single pulses. This process exposes the first wall to microshrapnel, unconverted light, x-rays, and neutrons. B4C is a low Z material that offers high depth x-ray absorption to minimize surface heating, is not activated by neutrons (will not become radioactive), and offers high hardness and vapour temperature. The long term operation envisioned within MCF reactors, where a continuous nuclear fusion of the fuel is sustained within the confinement of a magnetic field, favours the use of high Z materials, such as W, to protect the plasma exposed deflectors. The reason is a lower erosion rate and a shorter ionization distance in the plasma, which favours the redeposition of the sputtered atoms, both resulting in a lower contamination of the plasma. The production of the first wall and the deflector shields using solid B4C and W materials respectively, is obviously unthinkable. However, ProTeC has developed high density coatings for both ICF and MCF nuclear fusion reactors. W coatings with less than 2% porosity have been produced for both, the Tokamac MCF reactor and its Toroid Fueler. The toroid fueler is a plasma generating device designed to accelerate particles and inject them into the centre of the operating fusion reactor in order to refuel. For the application in an ICF reactor, B4C coatings exhibiting porosity levels below 3% with a hardness above 2500 HV have been deposited directly onto Al substrate. Properties such as outgassing, resistance to erosion and shrapnel, and the influence of x-rays have been studied and showed exceptional results.
Hydroxyapatite-Bond Coat Systems for Improved Mechanical and Biological Performance of Hip Implants
Authors: Heimann R.B. , Kurzweg H. , Vu T.A. 
Published: May 2021

Abstract
Bond coats based on bioinert ceramic materials such as titania and zirconia were developed to increase the adhesion strength of the coating system hydroxyapatite/bond coat to Ti6A14V alloy surfaces used for hip endoprostheses and dental root implants. The bond coats improved the adhesion strength, measured by a modified ASTM D3167-76 peel test, by 50 to 100% and also the resorption resistance as determined by in vitro leaching in simulated body fluid (Hank's Balanced Salt Solution, HBSS) for up to 28 days.
Properties of Coated Tools for Improved Performances
Authors: Rosso M. , Bennani A. , Rastrelli R. 
Published: May 2021

Abstract
The degradation of materials, connected to ageing and wear, can be limited by suitable treatments aimed at the increase of surface properties Among the surface modification techniques thermal spraying processes allow a lot of advantages improving the performance and extending the life of materials and components. The convenience for the substitution of nodular cast iron with coated steel for the manufacture of rolls to be employed in a rod mill plant was studied by means of disk on disk wear tests on plain carbon samples coated with the fuse and spray technology, using 7 different type of nickel or cobalt based powders, comparing their wear resistance with the behaviour of nodular cast iron specimens. On the basis of the wear tests, the most promising coating materials were applied to steel rolls and their behaviour and duration on a rod rolling plant were compared with those of nodular cast iron rolls. The rolls coated with nickel based alloy admixed with WC-Co powder reached the best performance, with a duration about 40 % higher than the cast iron ones.
Fe-AI Intermetallic Coating Applications to Thermal Energy Conversion Advanced Systems
Authors: Magnee A. , Offergeld E. , Leroy M. , Lefort A. 
Published: May 2021

Abstract
In many industrial processes, metallic materials are subjected to high temperature corrosion and aggressive forms of erosion. Such conditions occur especially in thermal energy advanced systems using tube bundles of fluidised bed boilers. For these types of plants, availability and low costs determine the choice of materials and in most cases this choice is not optimised for middle or long-term behaviour. Moreover, few data exist to estimate material lifetime under such aggressive conditions. Such is the case for low carbon steel grades which constitute the basic materials for these plants. New FeAl intermetallic alloys have been developed in the framework of a European collaboration, and it has been seen that these materials have good corrosion and erosion resistance properties at high temperature. Heat exchanger tubes in low carbon steel have been coated by thermal-spray then tested in a new industrial plant burning a very poor fuel (coal residues). After 5000 hours of operation in a rich erosive high temperature environment (850-900°C), no significant wear was observed on coated tubes whereas the other tubes, without protection, showed an appreciable diameter reduction.
Obtention and Development of Blends of Powder to Obtain Free-Standing Components Produced by HVOF Spray-Forming
Authors: Guilemany J.M. , De Paco J.M. , Miguel J.R. , Llibre J. 
Published: May 2021

Abstract
The feasibility of using the HVOF process for the thermal spray-forming of free-standing components has been investigated. HVOF spray forming offers a number of potential advantages compared to the established procedure of plasma forming, including increases in component density, and reduction in material decomposition during spraying. Using blends of carbide and superalloy powders in various proportions, HVOF spraying has been successfully used to form free-standing cylinders and cones of various lengths and thicknesses. Microstructural examination of the spray-formed material, using optical microscopy and scanning electron microscopy (SEM), has shown a homogeneous distribution of carbides in the superalloy matrix, with very low levels of porosity. Vickers microhardness has been measured on several sprayed forms. In order to complete the study of the different systems, abrasion (Rubber Wheel Test), friction (Ball on Disk Test) and erosion wear results have been obtained. These wear results have been used in order to evaluate the behaviour of the sprayed samples with a different powder percentage in the blends. Corrosion tests have been done to evaluate the corrosion resistance of the sprayed samples (ASTM D-1411).
New Powdered Silicide Materials for Thermal Spraying Process and Coatings on the Niobium Base Alloys
Authors: Terentieva V. , Bogatchkova O. , Cornu D. 
Published: May 2021

Abstract
The given article presents some results of the scientific research devoted to the development of a new class of scale-resistant powder materials of the Si-Ti-Mo-B system for thermal spraying and using these materials for the creation of heat-resistant coatings on the niobium base alloys by means of various methods of thermal spraying. Also under consideration are problems relating to the theory and practice of obtaining reliable protective coatings on high-melting metals and their alloys, niobium ones included, intended for operation in high-enthalpy oxygen-containing gas flows. Hazard in commencing an oxidation reaction of the base material under coating is connected with density of open pores and cracks, and partial pressure of the oxidizer. Powdered multicomponent heterophase materials for gas-thermal spraying of protective coating with a self-healing ability and controlled properties are proposed. Finally the results of some properties of new silicide-type heterophase powders containing silicide and boride phases for a thermal spraying process and some properties of protective coating deposited on the niobium base alloys by means of a thermal spraying technique are presented.
Molybdenum Disilicide Composites Produced by Plasma Spraying
Authors: Castro R.G. , Kung H. , Hollis K.J. , Bartlett A.H. 
Published: May 2021

Abstract
The intermetallic compound, molybdenum disilicide (MoSi2), is being considered for high temperature structural applications because of its high melting point and superior oxidation resistance at elevated temperatures. The lack of high temperature strength, creep resistance and low temperature ductility has hindered its progress for structural applications. Plasma spraying of coatings and structural components of MoSi2-based composites offers an exciting processing alternative to conventional powder processing methods due to superior flexibility and the ability to tailor properties. Laminate, discontinuous and in situ reinforced composites have been produced with secondary reinforcements of Ta, Al203, SiC, Si3N4 and Mo5Si3. Laminate composites, in particular, have been shown to improve the damage tolerance of MoSi2 during high temperature melting operations. A review of research which has been performed at Los Alamos National Laboratory on plasma spraying of MoSi2-based composites to improve low temperature fracture toughness, thermal shock resistance, high temperature strength and creep resistance will be discussed.