bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Substrate Surface Condition on the Flattening Behavior of Impinging Splat
Authors: Li H. , Liao H-L. , Costil S. , Coddet C. 
Published: August 2022

Abstract
Thermal spray coatings are formed by successive molten droplets impinging onto a substrate. It is commonly admitted that the flattening behavior determines the interaction of splats with the substrate or previously deposited under layer and hence governs the overall quality of the sprayed deposit. Therefore a number of works have been devoted to explain the splashing mechanisms and the flattening behavior from different aspects, such as fluid dynamics, solidification behavior, surface wettability or surface adsorbates/condensates. It was thus shown that surface conditions such as surface roughness, contaminants, adsorption, etc. play a very important role in controlling the splat flattening behavior. In this study, the role of the substrate condition as well as that of the impinging particle parameters are emphasized in the case of a copper deposit formed on a titanium base alloy and on a stainless steel substrates. The plasma sprayed copper splats were examined for different surface conditions. It was thus confirmed that favorable surface conditions tend to suppress splashing and to promote the occurrence of disc-shaped splats while the substrate nature and particle parameters also affect the splat flattening behavior. Results also indicated that disc-shaped copper splats prepared on a cold substrate have a smaller flattening degree than those obtained on a preheated substrate.
Microwear in Thermally Sprayed Hard Coatings by Different Abrasives
Authors: Eronen V. , Ahmaniemi S. , Niemi K. , Vuoristo P. 
Published: August 2022

Abstract
Microscale wear mechanisms in thermally sprayed hard coatings were examined. A test procedure for examining microwear with various abrasives was developed. Different abrasivity of kaolin, precipitated calcium carbonate and titania was found to affect wear mechanisms. Fine-particle abrasion caused the surface to loose its gloss and smoothness. Coatings subjected to fine-particle abrasion were examined with optical gloss measurements and scanning electron microscopy. It was shown that in tungsten carbide based hard coatings the microscale wear was governed by preferential wear of the soft binder phase. However, also coating defects like pores or poorly adhered splats tended to provide nucleation points for microscale wear. It was found that coatings that performed well in dry-sand rubber wheel abrasion or wet abrasion tests did not necessarily have good microwear resistance. The results showed that different abrasives had effect on the wear phenomena and wear rate of hard coatings. Coatings also behaved differently and novel modifications in the composition affected the wear behaviour. In conclusion, the results provided deep understanding of the role of various abrasives in the wear phenomena of thermally sprayed hard coatings.
Correlation of Microstructure with Abrasion and Oscillating Wear Resistance of Thermal Spray Coatings
Authors: Wielage B. , Wank A. , Pokhmurska H. , Friesen E. , Grund T. , Schwenk A. 
Published: August 2022

Abstract
Detailed studies concerning influence of microstructural features on the resistance of different thermal spray coatings against dry abrasive wear (Taber Abraser test) and oscillating wear (ball on disk configuration) are carried out. Besides WC and Cr3C2 based cermet coatings produced by a triple cathode APS system with axial powder feed and by HVOF systems using kerosene fuel also APS Cr2O3 and Al2O3 coatings are tested. At the example of WC/CoCr coatings the influence of carbide size and content, powder size fraction, powder manufacturing process and spraying process parameters is studied. For APS Al2O3 investigations concerning the influence of powder feed rate and nozzle geometry of single cathode APS torch are imparted. Oscillating wear tests are performed using alumina and hardened steel balls as counter bodies. Coatings are characterized concerning phase composition and residual stress state by means of XRD. Additionally microstructure is evaluated by SEM investigations and micro hardness is measured. Guidelines for manufacturing of thermal spray coatings fitting the specific demands of the two applied wear conditions are deduced.
HVOF Coatings Properties of the Newly Thermal Spray Composition WC-WB-Co
Authors: Bouaricha S. , Legoux J.-G. , Marple B.R. 
Published: August 2022

Abstract
A new WC-WB-Co feedstock material was sprayed with two HVOF torches. During spraying, the in-flight temperature and velocity history were monitored using the DPV2000 tool. Coatings sprayed with both guns had a relatively high microhardness and good abrasion properties, even with a higher level of porosity for some coatings. This was explained by the nature of the matrix which was composed of an amorphous/nanocrystalline structure and W-Co-B phases. It is suggested that the matrix is harder than conventional binders such as cobalt, for instance, and exhibits a better cohesion with the WC hard phase.
Controlled Removal of HVOF Hard Coatings by Abrasive Water Jet
Authors: Ruusuvuori K. , Lahdenperä K. , Oksa M. , Turunen E. , Lundberg R. 
Published: August 2022

Abstract
This paper presents development of adaptive Abrasive Water Jet (AWJ) removal method for HVOF hard coatings. High pressure water jet using Al2O3 powder was used to remove WC-CoCr and Cr3C2-NiCr HVOF coatings in a controlled manner. As a result, coating thickness was reduced down to 10-20 µm without damaging the base material. With this novel method use of environmentally problematic chemicals can be avoided or reduced in coating stripping process. To control the coating removal process and to prevent unwanted base material erosion through jetting, a system capable of measuring the coating thickness non-destructively with adequate accuracy was integrated to the AWJ removal cell. Depending on the substrate and coating materials used, the applied measurement technique is based on the eddy current or X-ray fluorescence methods.
Improvement of Mechanical Properties of Alumina and Zirconia Plasma Sprayed Coatings Induced by Laser After-Treatment
Authors: Ctibor P. , Nohava J. , Karovicova I. , Chraska P. , Tuominen J. , Vuoristo P. 
Published: August 2022

Abstract
Alumina and stabilized Zirconia were plasma sprayed in air using the water-stabilized plasma torch. In the case of Alumina two different stand-off distances were applied at spraying. Nd-YAG laser was then used for additional treatment of plasma sprayed coatings. The laser was maintained in a quasi-continual regime and defocused from the surface to increase the treated coating's area. Energy density was varied together with the laser scanning velocity to ensure variance in thermal history of the treated surfaces. Microhardness, surface roughness and slurry abrasion resistance (SAR) were measured before and after the laser treatment. Results vary in dependence on the laser treatment's parameters. When the treatment results in substantial changes of the structure (up to a complete re-melting of the surface), enhancement of all measured properties was proven. It is demonstrated that the extent of change of mechanical properties can be correlated with optical properties of coating materials at the laser wavelength. Microstructural aspects of the laser treatment are discussed as well, especially at the boundary between the laser-annealed layer and the basic coating's microstructure. It is pointed out that laser overheating due to use of an extremely high energy density can cause delaminating of the coatings.
Influence of Reduction Process on the Microstructure and Composition of Plasma Sprayed Al2O3-3TiO2/CuO Composite Coating
Authors: Zórawski W. , Chatys R. , Jamrozek J. 
Published: August 2022

Abstract
Undesirable changes in the coating composition can be reduced if plasma spraying is performed in a special chamber with a regulated atmosphere, the process being extremely costly, though. Another method allowing changes in the structure of coatings is thermal treatment. Numerous works present and discuss the results of the research into the influence of carburizing, nitriding, and laser or electron beam treatment on the properties of plasma sprayed coatings. This work concerned composite coatings obtained by plasma spraying of the blend of Al2O3-3TiO2 and CuO powders, which were then reduced at an atmosphere of dissociated ammonia. Their chemical composition and morphology were determined by means of the EDS microprobe and the Joel 5400 scanning microscope respectively. It has been reported that the process of reduction contributes to the homogeneity of the coating, and that the modified structure contains Al2O3 and Cu. Abstract only; no full-text paper available.
The Laser Shock Adhesion Test (LASAT) for Production Control of Thermally-Sprayed Ceramic Coatings
Authors: Boileau S. , Guipont V. , Jeandin M. , Nivard M. , Berthe L. , Jerôme J. , Boustie M. , Li H. , Khor K.A. 
Published: August 2022

Abstract
The adhesion strength of a ceramic coating deposited through direct spraying on a roughened substrate is a key issue in the manufacture of high-quality coatings on industrial components. The purpose of this work was to develop a rapid and discerning procedure for establishing adhesion level of a ceramic coating on a metallic substrate. The Laser Shock Adhesion Test, namely LASAT, was successfully applied to ceramic coatings with irradiation impact on the metallic side. Suitable parameters were found to determine the LASAT adhesion threshold using a standard Nd:YAG laser source. With a laser-irradiated area of several millimetres in diameter, it allowed assessment of the coating threshold on several areas of a coated plate sample. A control procedure for a qualitative assessment of coating adhesion was developed. This testing procedure could be easily used in industry, with possible location of the LASAT unit near to the spraying booth, for a direct production control on coated sample to improve the tracability of manufactured parts. Additional work was carried out to investigate a quantitative approach of the LASAT test to ceramic coating. The purpose was to simulate the shock wave propagation with the RADIOSS® code (a 3D software originally developed for car crash simulation). This code was implemented to calculate the velocity of the material and corresponding pressure throughout the substrate and the coating during the shock wave release (less than 2 ms). Experimental VISAR profiles ('Velocity Interferometer System for Any Reflector') were monitored in the straight direction of the laser-irradiated area on the rear side. These experimental signals (velocity measures) of the ceramic coating could be fitted and compared with a fairly good agreement with simulated profiles obtained by RADIOSS®. This modelling work was the first step towards a more comprehensive coating adhesion strength calculation in the future.
Comparative Study of Wear and Corrosion Properties of Electric Arc Thermally Sprayed Coatings
Authors: Lima C.R.C. , Barrera R. , Camargo F. 
Published: August 2022

Abstract
The use of thermally sprayed coatings to improve wear and corrosion resistance of industrial components has been found to be an effective and viable choice. Coatings based on several materials can be used for such applications, including situations when they are combined, using distinct deposition methods. The analysis for choice of the ideal coating and application process should generally take into account both coating performance and cost. In this work a comparative study of three commercial coating materials is performed. The used coating materials are High Chromium (HCr), High Chromium + 420 Stainless Steel and 420 Stainless Steel + 1080 Carbon Steel wires applied by Electric Wire Arc Spaying. The obtained coatings are tested for wear (ASTM-G-65-91 rubber wheel test) and corrosion (ANSI/ASTM-B117 and Electrochemical Measurements). Coatings microstructure, microhardness and adhesion (ASTM-C633-85) are also evaluated.
Microstructure Characterization of WC-25%NiCr Cermet Coating by Plasma Laser Hybrid Spraying Technique
Authors: Kim H.-G. , Katayama S. , Ohmori A. 
Published: August 2022

Abstract
Thermal sprayed WC-metal binder cermet coating is widely used for their resistance to abrasive wear in various harsh environments and generally sprayed by high velocity oxy-fuel (HVOF) method and atmospheric plasma spray method (APS). However, even during HVOF spraying, WC-metal binder cermet powder has to be exposed to high temperature flame jet for heating and accelerating, furthermore, oxygen is usually entrained into the flame jet, the decomposition and decarburization of tungsten carbide owing to the oxidation of WC, cannot be totally eliminated. This frequently causes defects such as pores, cracks and unmelted particles, which deteriorate coatings properties. To improve the properties of sprayed coatings, numerous studies have been examined post treatments such as laser irradiation, diffusion treatment, hot isostatic pressing (HIP) treatment, sealing treatment. Laser irradiation was speedy treatment and simplicity of process control and enables not only the post treatment but also the pre and simultaneous treatment by combining with spraying process. However, it is not easy to produce a uniformly treated coating by conventional laser treatment method as desired. To obtain a near-uniform beam intensity for practical laser irradiation, a kaleidoscope was installed in a conventional YAG laser. In this work, laser beam properties of YAG laser equipped with a kaleidoscope and its effect on surface modification of WC-25%NiCr coating was investigated. Abstract only; no full-text paper available.
Hot Gas Atomized Melts - Potentials for Thermal Spray Powders
Authors: Wolf G. , Bendix D. , Faulstich M. 
Published: August 2022

Abstract
The atomization of molten materials using hot gases has advantages in comparison to the conventional gas atomization techniques. Some of these advantages favour the hot gas technology for the powder production for thermal spraying. Firstly, a considerably higher output of fine powder, in particular within the important particle size range between 5 and 30 µm, is a result of hot (inert) gas atomization. The reasons are the strongly increased gas exit velocity and the higher overall temperatures inside the interaction zone of the gas and the melt droplets. The enhanced shear forces acting on the molten liquid and the prolonged liquid state of the atomized particles lead to a more efficient atomization. Secondly, the extended time regime for liquid droplets facilitates the atomization of highly viscous melts, such as oxide melts, and results in more spherical particle shapes with good flowability. Thirdly, oxide or nitride powders can be generated directly from the molten metal by the usage of hot reactive gases or gas components for atomization. This paper describes the special features of a 25 bar hot gas atomization technique with pre-heated gases up to 1200°C and discusses its potentials for the generation of powders in view of their suitability in thermal spray applications.
Hydroxyapatite Coating of Biomimetic Polymer Composite Materials
Authors: Legoux J.-G. , Bureau M. , Priscillia G. 
Published: August 2022

Abstract
One of the largest successes of modern medicine is the total hip replacement. Presently this procedure has one of the highest success rate among surgical interventions, only second to the appendix removal procedure. However the lifetime of the prosthesis itself is still limited to 10 to 20 years, which means that for numerous patients replacement of the procedure will become mandatory. This replacement finds its origin in aseptic loosening of the prosthesis mainly caused by the formation of wear particles at articular joints and by the difference in stiffness between the bone and the metallic prosthesis leading phenomena called stress shielding. To overcome this problem, new designs of more biomimetic prostheses, with stiffness similar to that of cortical bone, are being studied. Among the latter, a novel design based on polymer composite materials of total hip replacement prosthesis is under development. One of the key characteristics of this biomimetic prosthesis is its hydroxyapatite coating, which permits Osseo integration (integration into the bone). Thermally sprayed hydroxyapatite coatings are already used successfully for metallic implants, but plasma sprayed hydroxyapatite coatings have yet to be developed for polymer composites due to quite challenging heat management and adhesion concerns. This paper describes and discusses the optimization of the plasma sprayed technique and the formation of the adequate underlayer enabling the plasma spray on highly heat sensitive substrate. Adhesion, shear and fatigue results are presented. Abstract only; no full-text paper available.
Optimizing of LVOF Spray Parameters to Coat Ceramics by Studying Particles In-Flight Characteristics
Authors: Modi S.C. , Modi A. , Rayudu G.R. 
Published: August 2022

Abstract
A new variant of LVOF system was developed to deposit ceramics. For this study Cr2O3 powder was used. To save on time and reduce mathematical iterations optimizing of parameters was carried out by using an online particle diagnosing system. The spray parameters were varied to study their influence on the particle in-flight characteristics. The parameters which gave best particle temperature and velocity was used for coating. The resulted coating was dense and hard.
Research on Microstructure and Properties of Ni-Al2O3 Coatings Produced by HVO/AF
Authors: Hangong W. 
Published: August 2022

Abstract
In the paper, Ni-Al2O3 coatings were prepared by HVO/AF . The microstructure and composition of the Ni-Al2O3 coatings were investigated by metallographic microscope, scanning electron microscope and X-rayed diffraction, Bonding strength and hardness and mechanics properties were tested. The experimental results show the Ni- Al2O3 coatings possessed high microhardness and higher bonding strength with substrate and excellent comprehensive mechanical properties. Abstract only; no full-text paper available.
Air Gas Dynamic Spraying of Powder Mixtures: Theory and Application
Authors: Maev R. , Aczel A. , Leshchynsky V. , Salloum G. , Islam M.-Ui 
Published: August 2022

Abstract
The Radial Injection Gas Dynamic Spray (RIGDS) technology of powder wear resistant coatings deposition is considered. A coating is created by injection of powders with variable composition into the supersonic air jet and deposited on the substrate. Functionally graded coatings with advanced mechanical and corrosion properties were produced and tested. It is shown that operational parameters of supersonic powder-gas jet have a significant influence on the coating’s microstructure, thus defining the high performance of the coating. Compaction and bonding of particles were analyzed. Shear localization features of the GDS process are also discussed.
Influence of the Spray Parameters and Particle Size on the Treatment of Fe-Cr and Stainless Steel Particles in Flight in APS
Authors: Ageorges H. , Ctibor P. , Fauchais P. 
Published: August 2022

Abstract
The aim of this paper is to study the influence of plasma spray set-up parameters, such as the hydrogen percentage in the plasma forming gas and arc current, as well as powder injection parameters: the carrier gas flow rate and injected particle size on the melting, vaporization and velocity of particles of a Fe-Cr based alloy and stainless steel AISI 316L. Particles were collected in flight in a cylinder where they were quenched by argon jets to prevent there flattening at impact and chemical interaction with their environment. After collection, particles were analyzed by SEM, EDS and X-ray diffraction. When the injected particle size was between 60 and 100 µm, particles collected in flight exhibit complex shapes with a mean diameter of 40 µm, and the higher was the percentage of hydrogen the smaller was the resulting mean diameter. This probably corresponds to an inefficient cooling by the argon jets resulting in particles impacting at the bottom of the collector and partially exploding. When the injected particle size was between 10 and 35 µm, collected particle were nearly spherical with almost the same mean diameter, but then the oxidation changed with spray parameters. Measurements of temperature and velocity of the in-flight particles during plasma spraying were done using the Spray Watch (Oseir, Finland) equipment. Relationships between in-flight particle parameters and characteristics of the collected particles were found. Abstract only; no full-text paper available.
Analysis of Bonding Mechanisms during Thermal Spraying
Authors: Kudinov V.V. 
Published: August 2022

Abstract
The paper is a brief overview of data obtained by A.A. Baikov Metallurgical Institute of the Russian Academy of Science in the field of bonding mechanisms for thermal spray processes. The following 3 phases of bonding are considered: forming of a physical contact between a particle and a substrate; activation of the contacted surfaces and possible chemical interaction between a spraying particle and a substrate; diffusion. Thermal and mechanical activation of a substrate are considered in the paper. It is shown that thermal activation by molten particles and substrate preheating have a major input into the bonding process of the thermal spray processes such as APS, twin wire arc and flame spraying with relatively low velocity of molten particles. Application of high velocity processes like HVOF, HVAF and Cold Spray changes the mechanism of bonding activation. In this case the deformation of a substrate in the contact zone and related bonding activation caused by dislocations play a major role in the bonding of a particle with a substrate. It is shown that the energy needed for bonding depends mainly on the properties of the substrate and the particle materials.
The Relation between the Morphology of Powders and the Spraying Parameters and Structure of Coatings in the HVOF Spraying
Authors: Huang X. , Zhang T. , Sun Y. 
Published: August 2022

Abstract
Research and selection the performance requirements for the coating, at the same time obtain the WC-Co powders with high efficient spray rate and low cost, through research on the relation between the WC-Co powders sprayed by the HVOF in different morphology and in different manufacturing process and the spraying parameters and structures of coatings. Abstract only; no full-text paper available.
Thermal Spraying of Basalt for Abrasion Protective Coatings using WSP, HVOF and APS
Authors: Oberste Berghaus J. , Moreau C. , Chráska P. , Chráska T. 
Published: August 2022

Abstract
Basalt, an abundant and inexpensive natural raw material, is a glass-ceramic with good abrasion-wear resistance and chemical stability. Traditionally cast-shaped into flag stones, pipe linings and even fibrous composites, basalt can be processed by thermal spraying, potentially yielding highly dense coatings with few defects. Such overlays can seal base materials for wear applications in corrosive environments. Basalt coatings are produced by a number of common thermal spray techniques, including water-stabilized plasma spraying (WSP), high-velocity oxy-fuel (HVOF) and conventional air plasma spraying (APS). In-flight particle temperature and velocities are monitored with a particle diagnostic system (DPV 2000). Using different feedstock size cuts, the attainable ranges of particle states are delineated. Spray parameters are selected for each of the processes, based on deposition efficiency and porosity criteria. For typical conditions, particle velocities vary from 100 m/sec for WSP to 800 m/sec with HVOF. The microstructure and composition of the coatings are evaluated by scanning electron microscopy (SEM) and EDS-SEM. Crystal phase analysis is performed by X-ray diffraction (XRD). Abrasion resistance (ASTM G-65) and hardness (Vickers) of the as-sprayed coatings are compared. The microstructures and tribological properties are related to the particle size, temperature and velocity distributions, which are distinctly different for each process.