bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of a Multi-Component Reacting Plasma Jet in Plasma Spraying
Authors: Fuchi Wang , Qunbo Fan , Lu Wang , Quansheng Wang 
Published: July 2022

Abstract
The present study is conducted to simulate the multi-component chemical reactions of a turbulent argon-hydrogen plasma jet flowing into the surrounding atmosphere under typical operating conditions. Based on the initial spraying process parameters, the temperature, velocity profiles and the basic chemical species at the nozzle exit are calculated, and then used for the boundary conditions of the next step, where the chemical reactions in the multicomponent plasma jet are calculated by employing the Eddy-Dissipation model and the Realizable k-ε turbulence model. As the result of the calculation, the distribution of the mole fractions of the products as well as the temperature and velocity distributions is discussed. The approach presented in this paper will be theoretically helpful to perform further analysis of the interaction between the plasma and the particles.
Computational Evaluation of Coating Characteristics in Ceramic Spraying
Authors: Sato T. , Solonenko O.P. , Nishiyama H. 
Published: July 2022

Abstract
Numerical simulation of a plasma spraying process from ceramic particle injection to a coating formation was conducted by integrating particle-laden plasma flow, ceramic splat formation and coating formation models. Velocity and temperature of both plasma flow and ceramic particles under an applied RF electromagnetic field were clarified by using the first model. Radial distributions of particle impact location, velocity and temperature were obtained based on both an unsteady effect of a plasma flow and distributions of particle size and injection velocity. Nextly, splat thickness and diameter of melted ceramic particles after impact on a substrate were clarified by using the particle impact velocity and temperature. Radial distributions of splat thickness and diameter became more uniform. Finally, coating thickness distributions were evaluated by using the last model. They were strongly influenced by particle size and injection velocity distributions.
Computational Model for the Prediction of the Temperatures in the Coating During Thermal Spray
Authors: Bao Y. , Zhang T. , Gawne D.T. 
Published: July 2022

Abstract
The temperature of a substrate during thermal spraying may have a significant influence on the quality of coatings, especially for low-temperature materials such as polymers. The temperature must be high enough to thermally activate the interfacial bonding mechanisms but low enough to avoid degradation of the coating material or the substrate surface. It is thus necessary to understand and control the processes governing the temperature of the coating and substrate. However, thermal-spray deposition is a complex, dynamic process and the temperature distribution across the surface and through the thickness of the coating and substrate depends on many parameters. The scanning characteristics, the nature of the spray technique and the substrate dimensions are known qualitatively to influence the temperature profiles but the quantified inter-relationships are inadequately understood. It is difficult to characterize by experimental measurements the shifting patterns of temperature within the substrate because of the innumerable combinations of operating parameters. A computational model is therefore developed in this paper to simulate the temperature patterns during the deposition process. The influence of operating conditions, the spray technique and the dimensions of the substrate are taken into account in the computational model.
Modeling of Thermal Plasma Jets: A Comparison Between PHOENICS and FLUENT
Authors: Bolot R. , Li J. , Coddet C. 
Published: July 2022

Abstract
The modeling of thermal plasma jets is commonly used in order to obtain a better knowledge and understanding of the atmospheric plasma spray process. Many different software products are used in the literature at present but none of them present the same ease in integrating the plasma properties and none of them propose the same options: for example concerning turbulence modeling or concerning the implemented numerical methods. All that may result in differences in the converged solution and in the required computational time. For this reason, two different software products have been tested in the present study, namely the PHOENICS CFD code developed by CHAM (Wimbledon, UK) and the FLUENT CFD code developed by FLUENT Inc (Lebanon, NH, US). The comparisons concern different points such as the possibilities in implementing the plasma gas properties, the way the energy equation is considered, the available turbulence models or the implemented numerical methods. The conclusion indicates that some differences exist in the numerical results obtained using the two CFD packages.
Modelling of Plasma Jet and Particle Behaviour in Spraying Conditions
Authors: Delluc G. , Perrin L. , Ageorges H. , Fauchais P. , Pateyron B. 
Published: July 2022

Abstract
The numerical forecast constitutes an interesting way for plasma spraying to minimize the number of experiments to achieved the optimum spraying conditions. Many computational codes have been developed to predict the properties of the plasma jet (velocity, temperature) and the particles behavior within (temperature, velocity, melting state). According to the particle injection orthogonally to the plasma jet, the models have to be 3D. However, such codes need several hours if not several days of calculations to obtain the results of one condition. This is the main drawback of the existing sophisticated codes. The computing time is not compatible with industrial needs. Various clever numerical methods were developed in the past to simulate 2-D parabolic gas flows for laminar boundary layers or jets. For example, the Genmix 2-D axi-symmetric algorithm developed by Spalding and Patankar, and known as the Bikini method requires a very low-cost memory and computing time. This algorithm makes it possible, when using the proper thermodynamics and transport properties of plasma gases and the whole equation of Boussinesq-Oseen-Basset and taking into account the thermophoresis and non continuity effect for small particle, to predict in a fast and rather realistic way, the velocity and temperature fields of the plasma jet.
Numerical Simulation of Plasma-Sprayed Functionally Graded Coatings
Authors: Lu Wang , Qunbo Fan , Fuchi Wang , Quansheng Wang 
Published: July 2022

Abstract
Based on the mass flux distribution and dispersion rules of molten particles onto the substrate in plasma spraying, the 3-D shape and 2-D composition distribution map of functionally graded coatings are simulated by employing the grid method and Monte Carlo stochastic model. The models simulate the stochastic deposition according to an appointed stochastic operation number, allowing for the calculation of a large number of plasma spraying particles of different materials. In the analysis, the final mass distribution of the calculated coating is consistent with the initial mass flux distribution and reveals the process of coating formation, as well as the potential mechanism of the composition distribution.
Influence of Induction Plasma Gas Composition on Ti Coatings Microstructure and Composition
Authors: Shin D. , Gitzhofer F. , Moreau C. 
Published: July 2022

Abstract
Influence of induction plasma gas composition on Ti coatings microstructure and composition has been studied. Plasma sprayed Ti powder and coatings were prepared by using induction plasma system. Spheroidization of irregular shaped particles was observed in the powder collected after spraying with Ar-air plasma. Microstructures of the coatings were analyzed by a high-resolution scanning electron microscope. Image analysis of the backscattered images of the cross-sectional view of the coatings was used to calculate coating porosities. X-ray diffraction analysis was also performed to identify secondary phases, which have been formed in the coatings during plasma spraying. Partially induced nanostructures were observed in fractured areas in the coatings. The nanostructures were preferentially formed on the surface of splats. X-ray diffraction pattern reveals that a secondary phase has been formed in the coatings during spraying with air vol. at 16 % and 20 % in plasma gas. Changes of the coating density and thermal diffusivity were studied with respect to the formation of secondary phases and induced nanostructures.
Inductively Coupled Plasma Processing of Nano-Sized Calcium Phosphate Powders
Authors: Xu J.L. , Khor K.A. , Gu Y.W. , Cheang P. 
Published: July 2022

Abstract
A novel thermal plasma process, based on inductively coupled plasma torch is employed for producing nano-sized calcium phosphate powders from spray-dried hydroxyapatite (HA) feedstock. The phases during plasma process of HA feedstock under different working conditions have been studied. It is revealed that amorphous calcium phosphate is predominant in the nano-sized powders. HA, α-TCP and CaO are also detected in the nano-sized powders. After heat treatment at 800 °C in air, β-Ca2P2O7 (β-DCP) and HA are found to dominate in the powders. The presence of β-DCP is attributed to the HA feedstock directly decomposed into DCP in the plasma flame, and this phase formed amorphous calcium phosphates region by the rapid quenching process. This region crystallized into β-DCP after heat treatment.
Characterization of Nanostructured and Conventional Cermet Coatings by Controlled Scratch Testing: Correlation with Abrasion and Hardness Tests
Authors: Marple B.R. , Hawthorne H.M. , Xie Y. 
Published: July 2022

Abstract
Controlled scratch testing, dry abrasion tests and hardness measurements were performed on WC-12Co coatings produced by the high velocity oxy-fuel spraying of nanostructured and conventional feedstock powders. The information obtained employing these different evaluation techniques was used to provide insight into coating behaviour and identify the most abrasion-resistant coatings. The results indicated a correlation between scratch hardness and the microhardness determined by Vickers indentation for the coatings. There was good agreement between the scratch test and the abrasion test in identifying the best coatings for use in dry abrasion. Observation of the scratched surfaces and wear scars indicated material removal by splat debonding and fracture. The results demonstrate the usefulness of the scratch test for assessing the abrasion resistance and wear behaviour of coatings.
Comparative Study of Nanostructured and Conventional WC-Co Coatings
Authors: Morks M.F. , Shoeib M.A. , Ibrahim A. 
Published: July 2022

Abstract
Conventional (micron size) and Nanostructured (multimodal) WC-Co powders were sprayed on Al alloys using JP 5000 HVOF system. The coating microstructural characteristics and phase composition were investigated using SEM and XRD. The morphology and microstructure of nano-powders were also analyzed by SEM and XRD. The crystal size of the different phases was also investigated. The results show that nano-structured coatings have additional phases of W2C beside WC phase. Abrasion and hardness resistance of the coatings were also investigated. The results show that the wear and hardness resistance of the nanostructured coating is higher than the Conventional coating.
Nanophase Partially Stabilized Zirconia Intermediate Layer for Strain Accommodation in a Multi-layer Thermal Barrier Coating
Authors: Guru D.N. , Palacio M. , Mook W. , Chambers M. , Heberlein J. , Gerberich W. , Racek O. , Berndt C.C. 
Published: July 2022

Abstract
Applying an environmental barrier coating (EBC) and a thermal barrier coating (TBC) on the next generation gas turbine structural materials such as silicon carbide matrix composites will lead to large stresses due to thermal expansion mismatch; thereby limiting the coating's effectiveness and lifetime. Nanostructured materials possess a large volume fraction of grain boundaries and are conjectured to partially relieve the strain in the coating structure. A Triple Torch Plasma Reactor (TTPR) was used to spray multi-layered TBCs consisting of a mullite EBC deposited either on a silicon carbide or a mullite substrate, a nano-phase partially stabilized zirconia coating (n- PSZ), and a yttria stabilized zirconia coating (YSZ) as the TBC. The nanostructure of the n-PSZ could be maintained during the deposition process. The coatings were heat treated at 1300°C and the change in microstructure and mechanical properties were analyzed using scanning electron microscopy (SEM), micro-indentation and scratch testing applied to the coating cross section. While a change in the microstructure was observed, in particular grain growth, the hardness and elastic modulus appeared to be little affected by the heat treatment giving a preliminary validation of the multilayer concept.
Nano Structured WC-12Co Coatings Sprayed by HVO/AF
Authors: Zha Bailin , Wang Hangong , Su Xunjia 
Published: July 2022

Abstract
A supersonic flame was produced in HVO/AF through the combustion of kerosene and the mixture of oxygen and air. The flame Temperature can be adjusted between 1400 and 2800 °C through changing the flux ratio of oxygen and air in the mixture. Three kinds of nanostructure WC-12Co coatings were sprayed by HVO/AF under three different spray conditions. Experiments results show that the coatings bond well with the substrates with very dense structure. The decarburization reduces with the decrease of flame temperature. Nanostructure coatings were much denser than microstructure coatings with about 0.4 to 0.5 times increase in microhardness.
The Relationship of Work Distortion and Surface Roughness on Grit Blasting Process
Authors: Abukawa S. , Kobayashi K. , Kobayashi Y. 
Published: July 2022

Abstract
In order to utilize the blasting process for preparing surfaces of precision products, the factors affecting the work piece distortion and the degree of the distortion were investigated. The long and flat shaped specimens of the different materials and the thickness were blasted, and the phenomena induced by the blasting were investigated. In the result, almost the linear relationship between the surface roughness and the maximum deflection existed. In addition, the equivalent load was applied to the simple model of the distortion, and the correlative expression among the maximum deflection, the specimen's size, and the equivalent load was deduced. The results made it possible to select and design beforehand the products, and to optimize the blasting condition.
New Developments in the PROTAL Process
Authors: Costil S. , Li H. , Coddet C. 
Published: July 2022

Abstract
To avoid constraints due to the conventional surface preparation before thermal spraying (degreasing and sandblasting), the PROTAL process was developed implementing a Q-switched Nd-YAG laser to prepare the surface simultaneously to the coating build-up. The original system was designed with a single laser head and could meet with some limitations versus the thermal spray plume size, for example in the case of HVOF or twin wire arc spraying. In this work, a device with two laser heads was implemented thus increasing the size of the surface area which is prepared to receive the impinging material droplets. Then, after a presentation of the integration of such laser system in the thermal spray environment, some results will be presented. No significant surface topography modification can be noticed after the laser beam impact, this paper aims at clarifying the bonding mechanisms of thermal spray coatings manufactured implementing the PROTAL process. The case of a metallic coating deposited on a metallic substrate is especially discussed.
Pack Boronizing of HVOF-Sprayed WC-Co Coatings
Authors: Niinobe K. , Watanabe S. , Itakura K. , Sakoda N. , Tajiri T. 
Published: July 2022

Abstract
The effect of pack boronizing on microstructure and hardness of WC-12wt%Co coating sprayed on a low carbon steel (SS400) was studied using two kinds of HVOF-sprayed WC-Co coatings consisting of a single phase of WC and several phases of WC, W2C and Co3W3C, respectively. Pack boronizing was applied at 1273K for 3.6ks under an argon flow atmosphere, using 5%B4C, 5%KBF4 and 90%SiC powders. Microstructures obtained were characterized by X-ray diffraction, SEM and EDX analyzer. After boronizing, WC and CoW2B2 phases were detected in the both sprayed WC-Co coatings. This suggests that not only WC but also W2C and Co3W3C of WC-Co coatings decomposed by boronizing, resulting in the development of CoW2B2. However, many porosities with a size of more than 10µm were formed on the coating consisting of WC, resulting in a low hardness of HV600. On the contrary, the coating with W2C and Co3W3C has little porosity and a high hardness of HV2600.
The Influence of Post Heat Treatment Processes on Thermal Fatigue Resistance of Thermally Sprayed Coatings
Authors: Abdel-Samad Abdou , Lugscheider E. , Bobzin K. , Maes M. 
Published: July 2022

Abstract
Die-casting moulds are subjected to severe conditions of cyclical thermal and mechanical loads, as well as chemical and mechanical wear. Dies mostly fail due to a combination of wear mechanisms. Heat checking, erosion, melt corrosion and soldering often lead to complete die failure. Ceramic plasma-sprayed coatings have a great potential for die protection, since they are chemically inert, and show high form stability at elevated temperatures. Furthermore, they show good resistance against thermal shock due to the porous state of the coated layer and low Young’s modulus. In the present study, the influence of hot isostatic pressing on thermal fatigue resistance of plasma spraying coatings is investigated. Thermal and thermomechanical tests were applied to characterise their ability to protect dies. The coatings were evaluated by residual stress measurements, metallography, hardness test and X-ray diffraction.
Effects of Sealing on Electrochemical Characteristics of WC-NiCr HVOF Sprayed Coatings
Authors: Koga Yoshito , Obata Hiroaki , Noguchi Masahiro , Tarumi Kiyohiro , Ogi Keisaku 
Published: July 2022

Abstract
The effects of resin sealing on WC-NiCr HVOF sprayed coatings were studied using the anodic polarization measurements and the potentiostatic polarization measurements in sulfuric acid aqueous solution. Three types of coatings, without sealing, with sealing applied once and twice were prepared. Regarding the anodic polarization measurements the current densities of the coatings with sealing were less than that of the coating without sealing in the potential range of 0.1 V to 1 V (vs. Ag/AgCl, sat. KCl). According to the potentiostatic polarization measurements the current densities of the coatings with sealing were also less than that of the coating without sealing. Fe was detected in the electrolyte which the coating without sealing was immersed in on the potentiostatic polarization measurements. This meant that the substrate dissolved into the electrolyte because the coatings contain Fe less than 0.13 wt%. In addition, the coating sealed once were compared with that sealed twice. And it became clear that sealing effectively prevents substrates from dissolving and improves corrosion resistance of coating in sulfuric acid aqueous solution, which agreed with the result of salt spraying test.
Strengthening Alumina Protective Layer on MCrAlY Atmospheric Plasma Sprayed Coating by Chromate Processing
Authors: Teratani T. , Suidzu T. , Tani K. , Harada Y. 
Published: July 2022

Abstract
The high temperature oxidation resistance behavior of atmospheric plasma sprayed CoNiCrAlY coating with a thin layer of Cr2O3 employing chromate treatment was investigated. The high-temperature oxidation test was performed at 1423K for 7.2, 14.4 and 32.4ks, respectively. The formation of the oxide layer on the CoNiCrAlY coatings with Cr2O3 thin layer by chromate treatment was compared with that of the non-Cr2O3 thin layer. The oxide layer formed on the both types of MCrAlY coatings grows with increasing the elevated temperature and the holding time. Also, the thickness of the oxide layers was proportional to the square root of time. The thickness of the oxide layer on CoNiCrAlY coatings with the thin layer of Cr2O3 was only 60% as compared with that of the non-Cr2O3 thin layer in high temperature oxidation tests at 1423K.
Effect of Measurement Technique on Particle Temperature and Velocity Values in a Plasma Spray Jet
Authors: Hussary N. , Outcalt D. , Craig J. , Parker R. , Heberlein J. 
Published: July 2022

Abstract
The distributions of spray particle velocity and temperature were determined with two different instruments, the SpectraViz (Stratonics, Laguna Hills, CA) and the DPV2000 (Tecnar Automation, Montreal, Canada). Experiments were performed with three different powders and a Praxair SG 100 plasma spray torch. The instruments differ by the method they use in imaging the jet ultimately allowing for measurements of velocities and temperatures. The average particle temperature values obtained are very close, indicating that different ways of imaging do not influence the measurement value. The values for the average velocities are in good agreement for two of the powders tested (Al2O3 and CrO2), however, for the YSZ powder a consistent difference in velocity values was found. It appears that for obtaining average values e.g. for process control, both instruments are equivalent.
Particle Diagnostics in Wire-Arc Spraying System
Authors: Pourmousa A. , Abedini A. , Mostaghimi J. , Chandra S. 
Published: July 2022

Abstract
Diagnostics of particles produced from Value-Arc 100 twin-wire-arc spraying system was found using DPV2000 monitoring tool. Effect of different operating parameters on the diagnostics of the particles, namely, temperature, velocity, and size distributions, were experimentally studied and discussed. It was found that the particle characteristics are not symmetric about the center line of the plume. It was also found that the divergence angle in the plane parallel to both wires is less than the divergence angle in the symmetry plane of the wires, which is observed in the actual oval-shape coating structure and is explained by the geometry of the system. Size distribution and volumetric size distribution of particles are also analyzed and compared with log-normal distribution function. It is shown that the size distribution consists of two different peaks believed to be associated with anodic and cathodic particles in the process.
Tribological Properties and Microstructure of Plasma Sprayed High Silicon Aluminium Alloy Coatings
Authors: Mori H. , Nakanishi K. , Tachikawa H. 
Published: July 2022

Abstract
Plasma spraying was carried out on aluminium alloy substrates using high silicon aluminium alloy powders (Al- 40Si-Cu-Mg) to improve the wear resistance of the aluminium alloy. The coating exhibits superior more wear resistant to cast A390, and a low friction coefficient ranging from 0.2 to 0.25. The sprayed coating is much higher hardness of HV260 compared with that of cast A390, because of its quenched microstructure with sub-micron size silicon particles. The coating hardness does not decrease as annealing temperature up to 573 K, above 573 K it decreases rapidly. This drop in coating hardness is related to the coarsening of silicon particles and thus expanded interparticle distance. The wear resistance of coatings after annealing is inferior to that of sprayed coating. This is attributed to decrease in hardness value and coarsening of the microstructure. After annealing, the friction coefficient of the coatings shows a remarkable increase with increasing sliding distance. Since the plasma sprayed coating is in a non-equilibrium state, it maintains low friction coefficient even with a long sliding distance. Therefore, improvement in tribological properties is considered here to be due to change in wear mechanism brought by the formation of film-like layer, which prevents coating surface from adhering to iron.