bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Numerical Investigation—Air Plasma Spraying by Means of a Three-Cathode Spraying Torch
Authors: Bobzin K. , Öte M. 
Published: August 2022

Abstract
Newly-developed multi electrode spraying systems have improved the process stability and coating properties in air plasma spraying (APS) significantly. The new generation three-cathode torches, i.e. TriplexProTM-200/210, can be operated without significant plasma fluctuations. In previous studies a numerical model, which couples fluid dynamic, electro-magnetic and thermal relationships to investigate the flow characteristics in the torch were introduced. In this study further development of the model with respect to meshing and turbulence model will be introduced. Furthermore, free jet simulations will be conducted which use temperature and pressure profile at the outlet of the torch as inletting boundary conditions. Advanced diagnostic methods will be implemented to verify the capability of the numerical models.
Al/Al2O3Cermets by Plasma Spraying—Optical Response of Experimental and Numerical Materials
Authors: Toru D. , Quet A. , Piombini H. , Bianchi L. , Echegut R. , De Sousa Meneses D. , Del Campo L. , Echegut P. 
Published: August 2022

Abstract
Normal hemispherical spectral reflectances of plasma sprayed Al2O3/Al cermets were measured from visible to infrared wavelengths for several metal concentrations ranging from pure alumina to aluminum. Microstructure and composition of the samples were carefully characterized to explain their optical response, highly dependent on volume and/or surface scattering. Besides their contribution to the knowledge of microstructure, 2D scanning electron microscopy and 3D micro-tomography images were exploited to get statistical data in order to generate simplified numerical samples. A Monte Carlo ray-tracing model was then intended to reproduce experimental trends of the optical spectra. A good agreement with the experimental data was obtained.
An Investigation on Microstructural Properties of Plasma Sprayed Tungsten Carbide Enhanced with Partially Stabilized Zirconia
Authors: Abuali Galedari S. , Salimi Jazi M. , Azarmi F. , Tangpong A. , Huang Y. 
Published: August 2022

Abstract
Tungsten carbide coatings are often applied to improve surface properties such as wear, high temperature degradation, and corrosion resistance. Zirconia coatings have also been used extensively in various industries due to their excellent tribological and insulation properties combined with high stiffness. It is speculated that adding zirconia to tungsten carbide may result in a coating with combination of excellent thermal and mechanical properties of constituents. In the current study, a powder mixture of 50 wt. % WC-Ni and 50 wt. % ZrO2-Y2O3 deposited on a low carbon steel substrate using atmospheric plasma spray technique. The microstructural evolution of deposited sample was investigated. Splat boundaries, micro cracks, pore morphology conversion, and grain growth mechanism were elucidated comprehensively. Results indicated a good adhesion between two different major components. No porosity formed due to mismatch between zirconia and tungsten carbide. This study pays special attention to the dependency of the microstructural characteristics to the phase distribution within the coating.
Ceramics Filler Rods Feeding for Plasma Flame Torch in Thermal Nanoparticles Spraying
Authors: Kirihara Soshu 
Published: August 2022

Abstract
Using nanoparticles filler rod feeding, fine coated layer can be formed successfully with higher deposition late. Nanometer sized alumina particles of 200 nm in average diameter were dispersed into liquid resins at 40 % in volume fraction. The obtained pastes were solidified through heat polymerization to crate composite rods of ᶲ4×200 mm in dimensions. The solid rods were introduced into an acetylene and oxygen gas flame torch for a coaxial direction at 5.0 mm/s in supplying speed by using a mechanical actuator. Fine coated layer of 500 µm in thickness could be formed at 100 µm/s in deposition rate on stainless steel substrates. Effective dielectric constants of these coated layers were measured to estimate porosities by time domain spectroscopic method of electromagnetic waves in a terahertz frequency range. The reducing porosities in the coated layers through the optimization of filler rods feeding speeds and nanoparticles deposition rates will be discussed.
Comparison of Simulated and Experimental Particle Mean Temperature and Velocity for Thermal Spray Coating Process
Authors: Shang S. , Batra R.C. , Cybulsky M. 
Published: August 2022

Abstract
We numerically solve the system of nonlinear and coupled partial differential equations expressing the conservation of mass of species, the total mass, linear momentum, and energy, the k-ε turbulence model for plasma flow, the lumped heat capacity model for particle heating, and Newton’s equations for the particle motion under pertinent initial and boundary conditions. The interaction between the powder particles and the plasma is modeled by considering the drag force the plasma exerts on the particles and vice versa. The effect of particle vaporization as well as that of turbulence modulation on the mean velocity and the mean temperature of particles is also considered. The initial-boundary-value problem has been numerically analyzed by using the recently developed software, LAVA-3DI. The computed results are found to agree well with the test observations reported in the literature.
Constrained Healing and Morphology Change Mechanism of 2D Cracks in Plasma Sprayed Thermal Barrier Coatings
Authors: Li Guang-Rong , Lei Juan , Yang Guan-Jun , Li Cheng-Xin , Li Chang-Jiu 
Published: August 2022

Abstract
The stiffness and thermal conductivity of thermal barrier coatings (TBCs) are inevitably changed by healing up of intersplat pores and intra-splat cracks during high temperature exposure, which results in less compliance and thermal insulating performance. However most publications on sintering of plasma sprayed TBCs are based on free-standing coatings, which ignore residual stress and the stress produced by the mismatch of thermal expansion coefficient between substrate and ceramic top coatings. In this paper, individual splat of YSZ and YSZ coatings have been sprayed on substrate of YSZ and Ni-based superalloy. Evolution of healing and morphology of 2D cracks and some properties, such as hardness and thermal conductivity, have been revealed during thermal exposure. Results showed that, during heating stage, the shear stress coming from substrate caused some tearing of bonding area tips and narrowing of inter-splat pores. Some recoverable and unrecoverable widening on intra-splat cracks occurred also due to shear stress. During annealing stage, compared with free-standing coating, the surface hardness of the coating deposited onto the Ni-based superalloy showed enhanced increasing due to the faster healing of inter-splat pores by narrowing down, and the hardness in cross-section presented retarding increasing due to the widening of cracks in out-plane direction leading to slower healing. The case of YSZ substrate fell between free-standing case and Ni-based superalloy. This would benefit the further in-depth understanding of the thermal cycling failure mechanism of plasma sprayed TBCs.
Detection and Avoidance of Unmelted Wire Pieces during Wire Arc Spraying
Authors: Eichler S. , Kirner S. , Zimmermann S. , Schein J. , Mayr W. , Zierhut J. 
Published: August 2022

Abstract
A real-time measuring system has been developed to record and analyze the fluctuations of burner voltage and current. The objective is to identify the occurrence of stripping unmolten wire pieces (cold shuts) and to detect corresponding spraying conditions. To identify voltage and current fluctuations causing cold shuts, high speed camera shots are synchronized with electrical measurements to analyze spraying parameters which were assumed leading to cold shuts. As a result, different cold shut conditions could be identified. The electrical cold shut identification then triggers a camera system, to capture online the size and velocity of cold shuts. Based on electrical measurements it is intended to detect wear of spraying equipment which leads to enhanced cold shuts occurrence during industrial spraying process.
Development of Thin WC-12Co Coatings Manufactured by HVOF-Spraying
Authors: Tillmann Wolfgang , Hollingsworth Peter , Baumann Ingor , Laschitzki Marcel 
Published: August 2022

Abstract
The thicknesses of HVOF-sprayed WC-12Co wear protective coatings usually range between 50 – 500 μm. These thicknesses ensure a homogeneous coating structure as well as sufficient material reserves for efficient wear protection. For applications which require high shape accuracies, a cost intensive finishing of the thick coatings, in terms of grinding and polishing, is necessary. Thus, smooth and thin coatings are favored. In this study, thin HVOF-sprayed carbide coatings are developed by means of fine sintered and agglomerated WC- 12Co powders (2 – 10 μm). The use of fine powders enables the reduction of the coating thickness down to values below 50 µm. To influence and adjust the thickness of the coatings the powder flow, the gun velocity and the track pitch were systematically varied. During these tests the hardness and the roughness of the coatings were scrutinized.
Effect of Type and Amount of Tungsten Carbides on the Abrasive Wear of Laser Cladded Nickel Based Coatings
Authors: Maroli Barbara , Dizdar Senad 
Published: August 2022

Abstract
Metal-matrix composite (MMC) coatings consisting of a nickel based metal matrix, providing toughness and tungsten carbides, providing wear resistance, are used in applications subjected to severe abrasive wear conditions. The aim of this work is to map the influence of type, morphology and amount of tungsten carbides in a nickel based matrix on the wear resistance and microstructure of laser cladded MMC coatings. Abrasive wear, evaluated according to ASTM-G65, is mainly influenced by the volume fraction of the tungsten carbides in the coating. Shape and microstructure of the tungsten carbides have a minor impact on this property, for similar degree of melting or dilution from the substrate material and size of the tungsten carbides. Microstructure analysis shows that the dissolution of the tungsten carbides in the melt pool is influenced by the chemical composition of the liquid metal phase, the microstructure and the amount of tungsten carbides selected.
Electron Microscopy and EBSD Characterization of Cold-Sprayed IN625 Coatings on 4130 Steel
Authors: Srinivasan Dheepa , Amuthan Ramar , Lau Y.C. , Chaudhuri Atanu , Raghupathy Y. , Suwas Satyam , Srivastava Chandan 
Published: August 2022

Abstract
The Cold spray method of material deposition is widely used for surface enhancement, to improve properties such as corrosion and wear. A detailed microstructural analysis of cold sprayed Ni based coatings (IN625 (Inconel 625 is a Trademark of Huntington alloys corporation) using the transmission electron microscope, revealed the occurrence of three distinct types of microstructures in the as sprayed condition, adjacent to each other. These include the occurrence of large (&gt; 1 μm) grains having a high dislocation density, along with regions comprising shear bands (20-30 nm wide) and twins with a large aspect ratio (&gt; 1000), along with locations having a very fine grained structure (20-30 nm). The crystallite size, using a Hall-Williamson plot measures an average 50 nm. The substrate deformation indicates a bilayer dynamic recrystallization, as a means to accommodate the strain. The microscopy studies will serve to correlate the bonding mechanism of cold sprayed IN625 on 4130 steel.
Epitaxial Grain Growth during 8YSZ Splat Formation on Polycrystalline YSZ Substrates by Plasma Spraying
Authors: Yang Er-Juan , Luo Xiao-Tao , Yang Guan-jun , Cheng-xin Li , Li Chang-Jiu , Takahashi Makoto 
Published: August 2022

Abstract
The effect of substrate template effect on the crystalline structure of plasma sprayed 8YSZ (8mol%Y2O3) splats was investigated by high resolution transmission electron microscopy (HR-TEM) examination of FIB-processed splat samples. 8YSZ splats were deposited by the atmospheric plasma spraying (APS) on the polished sintered tetragonal structure substrate (3YSZ) and cubic structure substrate (8YSZ) at different preheating temperatures. The focused ion beam (FIB) was utilized to prepared TEM cross-sectional sample of splats. The crystalline structures of both the splat and the underlying substrate were examined by HRTEM. Results showed that the 8YSZ splats deposited on the polished sintered cubic structure 8YSZ substrate at a substrate surface temperature of 900°C exhibited cubic structure and the epitaxial grain growth was confirmed between the crystalline of splat grain and immediately underlying cubic crystalline substrate grain. Moreover, epitaxial grain growth was confirmed between the crystalline of splat grain and the tetragonal structure substrate when substrate surface temperature was increased to 1200°C. The present results suggest that the crystalline structure formation of 8YSZ splats produced by plasma spraying was affected by the substrate template effect.
Experimental Investigation and Finite Element Simulation of Residual Stress Development in Thermally Sprayed Coatings
Authors: Elhoriny Mohamed , Wenzelburger Martin , Killinger Andreas , Gadow Rainer 
Published: August 2022

Abstract
In this study, coating buildup process of ceramic powder Al2O3 deposited on steel substrate by atmospheric plasma spraying is simulated by creating a thermo-mechanical FEA model that utilizes the element death and birth techniques in ANSYS commercial software. The simulation process starts with side-by-side deposition of coarse subparts of the ceramic layer until the entire coating is created. Simultaneously, the heat flow into the material, initial quenching stress, thermal deformation and particle impact impulse transfer are computed. The purpose is to be able to predict - for the considered spray powder and substrate material - the development of residual stresses and to assess the risk of coating failure. The model allows the prediction of heat flow, temperature profile and residual stress development over time and position in the coating and substrate. The proposed model has been successfully run and results were experimentally verified by comparing with actual residual stresses measured by the hole drilling method.
Fretting Behavior of Cold-Sprayed Cu and Cu-MoS2 Coatings
Authors: Zhang Yinyin , Chromik Richard R. , Descartes Sylvie , Regis Edouard , Vo Phuong 
Published: August 2022

Abstract
Cu and Cu-MoS2 coatings were fabricated by cold gas dynamic spray and the fretting wear performance of the two coatings was compared. A mixture (95 wt.% Cu + 5 wt.% MoS2) was used as feedstock for the composite coating. Coatings were sprayed with identical gas flow conditions on the substrates preheated to approximately 170°C. The cross section of the coatings was analyzed by scanning electron microscope (SEM) and MoS2 concentration was measured, as well as coating microhardness. Fretting tests were carried out under gross slip conditions in ambient environment. SEM observation on wear scars and counterspheres revealed the development of third bodies, by which the sliding was accommodated. For the Cu-MoS2 coating, solid lubrication effects in the form of friction drops occurred in early cycles (&lt; 5k), but eventually (&gt; 5k) the coating's friction behavior was similar to the pure Cu coating. Third body morphology and wear of the two coatings were distinctly different, which could largely be attributed to the hardness reduction of the Cu-MoS2 composite due to poorly bonded interfaces induced by the effect of MoS2 during particle impact and coating formation.
Fully Nano-Equiaxed-Structured Thermal Barrier Coating Deposited Using Very-Low-Pressure Plasma Spray
Authors: Gao Yang , Zhao Yan , Sun Cheng-qi , Yang D.-M. , Gao Jianyi 
Published: August 2022

Abstract
A novel fully nano-equiaxed-structured thermal insulation Y2O3-stabilised ZrO2 (YSZ) coating was first successfully deposited using very-low-pressure plasma spray (VLPPS) and the agglomerates feedstock from nanometer-sized powders. The microstructure of fully nano-equiaxed-structured coating is different from that of a “bimodal microstructure”, which is currently the dominant nanostructured coating. This desirable structure in the new TBCs appears to be responsible for their improved thermal cycling lifetimes and reduced thermal conductivity relative to those of conventional plasma-sprayed TBCs with lamellar structures or bimodal structures. Preliminary results from experiments aimed at understanding the VLPPS deposition mechanisms suggest that the nanometre-scale equiaxed in the coating are formed from original nano-particles, they underwent melted in the low pressure plasma plume and solidification onto the substrate. The VLPPS method, which offers some unique advantages over the conventional plasma-spray process, is generic in nature and can be potentially used to deposit a wide variety of ceramic coatings for diverse applications.
Homogenization of Coating Properties in Three-Cathode Atmospheric Plasma Spraying by Use of Advanced Diagnostics and Numerical Simulation—Investigations of Suspension Plasma Spraying (SPS)
Authors: Zimmermann Stephan , Schmettlach Sven , Weber Sebastian , Marques Jose , Forster Guenter , Landes Klaus , Schein Jochen , Lummer Christin , Knödler Patrick , Kresnik Simon , Prehm Jens , Möhwald Kai , Maier Hans J. 
Published: August 2022

Abstract
This paper discusses a research project with the goal of homogenizing the properties of three-cathode plasma sprayed coatings through the use of advanced diagnostics and numerical simulations. The approach included the development of a suspension injection setup, the determination of plasma and suspension behavior through diagnostic methods such as computer tomography and particle image velocimetry, and the analysis of coating formation through computational fluid dynamics and finite element analysis. The results of their investigations are presented, including tomographic reconstructions of temperature distribution, suspension behavior measurements, and coating analysis. The paper concludes with a discussion of the future directions of their research and the potential impact on the field of thermal spray coatings.
Improved Corrosion Resistance of Plasma-Sprayed NiCr-Mo Coating with Shell-Core-Structured Powder by Improving Lamellar Interface Bonding
Authors: Tian Jia-Jia , Yang Guan-Jun , Li Cheng-Xin , Luo Xiao-Tao , Li Chang-Jiu 
Published: August 2022

Abstract
The bonding between flattened particles in plasma-sprayed metal coatings dominates their corrosion behavior by influencing the porosity in coatings, especially the porosity connected to the substrate for coatings used in a corrosive environment. Therefore, how to efficiently enhance the lamellar interface bonding in metallic coatings has been an important issue which has not been settled effectively. In this study, a shell-core structured powder particle designing with cladding spherical Ni20Cr powders with refractory molybdenum as alloying element is proposed to limit the evaporation of low melting point elements and subsequently raise particle temperature significantly high enough to cause impact melting. Results show that a dense coating with much low porosity was obtained due to the improved lamellar interface bonding by gas shrouded plasma spraying of the composite NiCr -Mo particles. Electrochemical method was employed to evaluate the polarization behavior of the NiCr - Mo coating to estimate its connected porosity. It was revealed that NiCr-Mo coating of excellent corrosion resistance with low connected porosity can be obtained by designing the shell-core-structured powder.
Influence of Gas Flow Parameters and Nozzle Design on Secondary Atomization in a Rotating Twin-Wire Arc Spray System
Authors: Devillers Jean-Baptiste , Liao Hanlin , Coddet Christian , Malhaire Jean-Marie 
Published: August 2022

Abstract
Internal coating of cylinders has always been a challenge for cars engineers. Driven for more than two decades now by the ecological and economical constrains applied to the automotive industry, it constitutes a dynamic way of research and development for industrial applications. One of the most economical processes for this kind of coatings is the rotating twin-wire arc spray (TWAS) system. Meanwhile the actual quality and the performances of the corresponding coatings still leave place for some improvements. Therefore, in the work presented here, attention was paid to the second atomization phenomena in a TWAS system considering the influence of the gas flow parameters on the particles’ morphology and deposition behavior. Numerical modeling of the plume and comparisons between several designs of the second atomizing units were also considered.
Influence of Surface Oxide Film on Deposition Behavior of Cold Spray Emulated Particle by Single Particle Shot System
Authors: Ito K. , Ichikawa Y. , Ogawa K. 
Published: August 2022

Abstract
In a cold spray technique (CS), which used for making dense and thick metallic coatings, the fine solid metallic particles are impinged and deposited on a substrate at subsonic or supersonic velocity. The property and performance of a CS metallic coating significantly depends on the bonding state of particle-substrate and particle-particle interfaces. Therefore, the deposition mechanism of the CS particles has become one of the most important research targets. However, it is difficult to experimentally evaluate the deposition mechanism due to numerous impingements of very fine particles with various size and shape. In this study, in order to evaluate the deposition mechanism, a CS emulated environment was created by a single particle shot system (SPSS) in which spherical particle with 1 mm diameter is impinged on a substrate. The influence of substrate surface oxide film on deposition behavior of a spherical Al particle with 1 mm diameter was investigated. The thickness of surface oxide film on a substrate was controlled by heat treatment and estimated by X-ray photoelectron spectroscopy (XPS). Using the SPSS, Al particles were impinged on the substrates with different surface oxide film thicknesses. The critical velocity, which means the starting velocity for particle deposition, and the microstructure of deposited particle were evaluated. From the results, it was found that the surface oxide films on substrates play important roles on the deposition behavior of the Al particle.
Investigation of Flow Parameters in Wire Arc Thermal Spraying Using CFD Simulation
Authors: Farrokhpanah Amirsaman , Pershin Larry , Mostaghimi Javad , Naffrechoux Julien 
Published: August 2022

Abstract
Comprehensive study of the wire arc thermal spray technology will allow for better design and optimization of guns. In wire arc spray, a feed of two electrically-charged wires are melted using an arc. This bath of molten metal goes through an atomization process with a high pressure air being blown upon it. Flow of air will then carry the generated molten drops and deposits them on the substrate. The focus of this study is on the numerical simulation of wire arc sprays using ANSYS FLUENT software. Effects of geometrical parameters on resulting flow conditions and flow circulations inside the gun are studied. Simulation results help in better parameter selection for effective wire arc coating.