bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Nanocrystalline 316-Stainless Steel Coatings by High Velocity Oxy-Fuel Spraying
Authors: Lau M.L. , Jiang H.G. , Lavernia E.J. 
Published: May 2021

Abstract
The present paper describes the synthesis of nanocrystalline 316-stainless steel coatings by high velocity oxy-fuel (HVOF) thermal spraying. The feedstock powders were synthesized by mechanical milling to produce flake-shaped agglomerates with an average grain size of less than 100 nm. The powders were introduced into the HVOF spray to successfully produce nanocrystalline coatings. X-ray diffraction analysis and transmission electron microscopy were used to determine the average grain size of the milled powders. Scanning electron microscopy and transmission electron microscopy were used to study the morphology of the nanometric particles and the microstructure of the as-sprayed coatings. The properties of various coating materials were characterized by microhardness measurements performed on the polished surface of the cross section.
Numerical Modeling of an Impinging Dusted Plasma Jet Controlled by a Magnetic Field in a Low Pressure
Authors: Nishiyama H. , Kuzuhara M. , Solonenko O.P. , Kamiyama S. 
Published: May 2021

Abstract
The present study is conducted to clarify the magnetic control characteristics of a particle-laden plasma jet impinging on a substrate for the improvement of a low pressure plasma spraying process and its controllable optimization. The plasma jet is described by Eulerian approach and each injected particle is described by Lagrangian approach respectively taking into account the compressible effect, variable transport properties and plasma-particle interactions, coupled with the Maxwell's equations. The effects of the location of the applied radio-frequency electromagnetic field, and of the injected particle size on the particle trajectory, particle velocity and its phase change are clarified by numerical simulation. It is concluded that the particle trajectory is influenced effectively and the injected particle temperature can be controlled strongly by applying the radio-frequency electromagnetic field to the nozzle. The reasonable agreement of particle velocity between calculation and experiment is observed.
Plasma Spraying with Atmosphere and Temperature Control: Cryogenic Flux Modeling
Authors: Meillot E. , Legeay O. , Richet J.N. 
Published: May 2021

Abstract
Production of ceramic coatings by plasma spraying on thermally sensitive substrates requires a hard cooling onto the substrate immediately after the plasma and particles jet getting-through. That implies a cryogenic cooling spray. In order to have a better understanding of thermal transfer between cryogenic droplets and substrate, we simulate with a home-made software, PARTIX, the transport of pulverized jet in the atmosphere and calculate the droplet size distributions impacting the substrate. Knowing that, we can determine the thermal flux. Simulations of different pulverized flows are presented.
Thermal Spray Quasicrystalline Coatings Part I: Relationships Among Processing, Phase Structure and Splat Morphology
Authors: Sordelet D.J. , Besser M.F. , Kramer M.J. 
Published: May 2021

Abstract
A study was performed to examine the effects of starting powder composition, substrate thermal conductivity, and substrate temperature on the composition and structure of individual Al-Cu-Fe splats formed during thermal spraying. The fraction of quasicrystalline phase which formed was found to depend on the chemistry and solidification history of the splats. Due to evaporative loss of Al during spraying, an initial powder composition higher in Al produced splats closer to the desired composition, which yielded more of the quasicrystalline phase. Deposition onto lower thermal conductivity surfaces resulted in an increase in the quasicrystalline phase, as did solidification onto higher temperature substrates.
Effect of Particle-Substrate Materials Combinations on Morphology of Plasma Sprayed Splats
Authors: Li C.J. , Li J.-L. , Wang W.-B. , Ohmori A. , Tani K. 
Published: May 2021

Abstract
The structure and morphology of plasma sprayed splats are experimentally investigated using different droplet materials and substrate materials. Droplet materials include aluminum, copper, nickel and refractory metals such as molybdenum and tungsten, and substrate materials include aluminum, stainless steel, and molybdenum plates. The results show that the splashing occurs during the splatting of a completely molten droplet. Most splats formed by droplets molten completely are only central part of the ideal disk type ones, which are defined as the annulus-ringed disk-like splat. It is found that the morphology of such annulus-ringed disk-like splat is greatly influenced by the combination of droplet and substrate materials depending on whether substrate melting occurs. With the combinations of droplet and substrate materials which are of similar thermal properties the splashing of central area of splat tends to occur to present a honeycomb structure at the center of splat. When droplet impacting can cause melting of substrate annulus-ringed splat prefers to present a split type. The flattening ratio of an annulus-ringed disk splat is typically less than 2.
Morphology of Splats of Thermally Sprayed Coatings
Authors: Sobolev V.V. 
Published: May 2021

Abstract
Different mechanisms of splashing of droplets impacting onto the substrate surface during thermal spraying are considered. It is shown that supercooling formed in the flattening droplet consists of the thermal supercooling and that arisen due to the high pressure developed upon the droplet impact. Solidification starts when the supercooling exceeds some critical value. With a "cold" substrate when its temperature is less than a transition temperature the marked contribution to the supercooling is due to its high pressure part. In this case a regular disc-shaped splat will be formed in the central part of the flattening droplet and splashing will occur in the periphery. With a "hot" substrate when its temperature exceeds the transition temperature the thermal supercooling is high enough, no splashing occurs and a regular disc-shaped splat is formed. Theoretical results agree with the experimental observations.
Degradation of In-Flight PMMA Particles During Thermal Spraying
Authors: Zhang T. , Gawne D.T. , Bao Y. 
Published: May 2021

Abstract
Kinetic and heat transfer analysis have been undertaken in order to predict the decomposition of polymer feedstock particles during thermal spraying. Thermogravimetric measurements indicated that the decomposition of PMMA had an order of reaction of unity and an activation energy of 135 kJ mol-1. The polymer decomposition temperature is shown to be a function of the particle residence time in the flame and is much higher than in conventional polymer processing. This has an important influence on process modelling, since the choice of decomposition temperature used in the heat transfer analysis has a major effect on the calculated temperature profiles. The work shows that realistic predictive data can only be obtained by using the dynamic decomposition temperature. Application of the model indicates that only the surface layers of the polymer feedstock particles undergo significant decomposition during plasma spraying and that the feedstock injection position is an important control parameter.
Evaluation of Fatigue Strength of WC Cermet- and 13Cr Steel-Sprayed Materials and Their Coatings
Authors: Ogawa T. , Tokaji K. , Ejima T. , Kobayashi Y. , Harada Y. 
Published: May 2021

Abstract
Rotating bending fatigue tests have been conducted at room temperature in laboratory air using specimens of medium carbon steel (S45C), low alloy steel (SCM435) and titanium alloy (Ti-6AI-4V) with HVOF sprayed coating of a cermet (WC-12%Co) and S45C with WFS sprayed coating of a 13Cr steel (SUS420J2). Plane bending fatigue tests were also conducted at stress ratios, R, of -1, -0.5 and 0 for S45C with WC-12%Co coating. The fatigue strength and fracture mechanisms were studied. The fatigue strength evaluated by nominal stress was strongly influenced by substrate materials, R and the thickness of sprayed coatings. Detailed observation of crack initiation on the coating surface and fracture surface revealed that a crack was initiated in the coating and then cracks were initiated in the substrate due to the stress concentration of the crack in the coating. The fatigue strength of the sprayed materials was dominated by that of the sprayed coating. Therefore, the fatigue strength could be evaluated uniquely in terms of the true stress on the coating surface. The influence of compressive residual stress of the sprayed coatings on fatigue strength was discussed based on the fatigue mechanisms at different stress ratios.
Impact Evaluation of Plasma Spray Coatings
Authors: Shao T.M. , Xu D.J. , Luo J.G. , Wu C.-J. 
Published: May 2021

Abstract
Impact performance of plasma spray coatings is usually evaluated by means of surface observation after impact action. As a matter of fact, the dynamic response characteristics of coatings in the course of impact action are also very important. In this paper, a method of response frequency spectrum analysis is developed for the impact evaluation of plasma spray coatings. An impact test machine, in which the impact load is generated by a pivot-rod-lever system, is specially designed, allowing both single impact test and repeated impact test. The frequency spectra of Cr2O3 ceramic coating and WC-Co17% alloy coating under single and repeated impact action are analyzed. The results show that there is an obvious relationship between the impact performance and the impact response frequency spectrum. Abrupt changes in the coating, such as appearance of surface cracks and surface damage, correspond the sudden changes of the response frequency spectrum.
Internal Stresses in Plasma Coatings with an Amorphous Structure
Authors: Borisov Y. , Korzhyk V. 
Published: May 2021

Abstract
This paper examines the stress state of plasma-sprayed amorphous coatings of Fe-B with additions of Ni, Cr, and Mo. Internal stresses depend on the type of plasma gas used, the thickness and composition of the coating, and the material and temperature of the substrate. In this study, additional cooling of the substrate was found to be the most efficient way to reduce internal stresses. Amorphous coatings were also found to improve fatigue strength by as much as 25-30%, which is attributed to the formation of compressive stresses in the coating layers adjoining the substrate.
Quantities and Properties of Layers Sprayed with Cored Wire of Type Fe-Cr-C
Authors: Drzeniek H. , Milewski W. 
Published: May 2021

Abstract
Results of macro- and microhardness investigations of newly developed coatings are presented in this paper. The coatings were produced with flame- and arc spraying technique. The coating structure and hardness is significantly influenced by the spraying method and spraying parameters. It will be shown that properties for flame sprayed coatings are more effected by parameter variations than for arc sprayed coatings. A higher hardness, a greater density and a better particle cohesion can be obtained by using the arc spraying method.
Measurement Technology for Inflight Particle Diagnosis in Plasma Spraying
Authors: Schutz M. , Barbezat G. , Fluck E. 
Published: May 2021

Abstract
A new measurement technology in plasma spraying has been established at SULZER METCO AG, Switzerland. Based on the principle of C. Moreau, CNRC, it is now possible to simultaneously measure surface temperature and velocity of melted particles in a plasma flame. Since temperature and velocity are two of the most important parameters affecting coating characteristics in the thermal spray processes, the knowledge and control of these parameters offers new methods and assistance in the development of coating solutions. The object of this paper is to outline some important measurement results, to show correlations to splat formation and coating characteristics and to demonstrate applications in an industrial environment.
The Influence of Several Powder Feed Parameters on Feed Precision and Continuity
Authors: Huang X. , Xu L. , Ma X. , Fan B. , Yin X. 
Published: May 2021

Abstract
This paper provides a summary of conventional thermal spray powder feeders, examines the influence of carrier gas flow, powder tube diameter, powder tube type, and gas flow path on the feed precision and continuity of pressure-type powder feeders, and discusses the cause of pulsation associated with the injection of super fine ceramic powders.
Measurement of Spraying Particle Behaviors by Three-Intensified-Sensor Color High Speed Video Camera System
Authors: Yamakawa M. , Oki S. , Gohda S. 
Published: May 2021

Abstract
A high-speed video recording system was developed to measure the velocity and temperature of thermal spray particles in flight. The system consists of three image sensors and a cubic beam-split prism that directs light, based on color or wavelength, to three imaging planes. In this study, one of sensors is used to measure particle velocity while the other two measure particle temperature. The prospect of simultaneously measuring the temperature and velocity of individual particles in flight is discussed along with the insight it provides on the formation of spray coatings.
Comparison of Different Fuel Gases in HVOF
Authors: Gourlaouen V. , Verna E. , Sattonnet J. 
Published: May 2021

Abstract
Although high-velocity oxyfuel (HVOF) spray coating is a relatively new thermal spraying process, interest is growing rapidly along with the pace of development in areas such as torch design, powder quality, and modelling. The gases used in HVOF spraying are also important because they directly influence the state of the particle striking the substrate. This presentation reviews the HVOF combustion process with an emphasis on the gases used and their influence on coating quality.
Research on Heavy-Loading Thermal Spray Turntable with High Precision and Self Controlled Frequency Conversion
Authors: Huang X. , Xu L. , Wang R. , Wang J. , Yin X. 
Published: May 2021

Abstract
This paper discusses the basic design and operating characteristics of a precision heavy-duty thermal spray turntable. The system incorporates eccentricity and speed control and accommodates working pieces up to 100 mm in diameter and 2000 mm in height weighing as much as 1500 kg. Site tests, as reported in the paper, indicate that the turntable also meets dust and heat tolerance requirements.
Deposit Model for Offline Programming in a Spray Process
Authors: Montillet D. , Dombre E. , Valentin P. 
Published: May 2021

Abstract
This paper presents research work aimed at path planning for continuous processes; we treat the general case and examine thermal spraying in particular. The objective is to simulate the process for the offline programming of a sprayer robot. Integrating process models with those of the robot and workpiece in a single CAD environment simplifies the preparation and optimization of spraying tasks. This paper describes the principles and specifications of the application package with emphasis on the development of the process model and motion generation satisfying the constraints of thermal spraying.
Unusual Application of Plasma Sprayed Coating for Boiler Tubes in Oil-Fired Boilers
Authors: Tani K. , Harada Y. , Kobayashi Y. 
Published: May 2021

Abstract
The unusual effects of plasma sprayed coating on the fire-side of evaporator tubes located in an oil-fired steam generating boiler are discussed. The main heat transfer surfaces are constructed by heat exchanger tubes, evaporator tubes and superheaters. Maintenance to prevent of the boiler failure or the preserve heat exchanger effectiveness is a very important factor in the operation of boiler facilities. In a boiler which employs heavy gravity oil as a fuel, plasma sprayed Ni-Cr alloy has often been applied to boiler tubes for the relief of hot corrosion by combustion gas. However, the circulation of boiler water causes an internal deposit to form on the inner wall of evaporator tubes. The internal deposit generates excess heat load against the tubes. As the overheating of the tubes often causes the evaporator tubes to fail, they are chemically cleaned periodically. In this paper, the influence of Ni-Cr plasma sprayed coating for the heat flux, which dominates the formation of the internal deposit, is investigated. Ni-Cr plasma sprayed coating is substitutionally hot corrosion resistant and is a composite coating into which the fuel ash containing a vanadium or sulfur compound are interstitially penetrated and solidified. It is derived that the existence of the coating on the fire-side of the evaporator tubes normalizes the heat load in their inner walls. Moreover, the suppression of internal deposit formation decreases the frequency of chemical cleaning for tubes. The dual effects of plasma sprayed coating for hot corrosion resistance in the fire side and the suppression of internal deposit on the water side of the tubes are reported.
Internal Plasma Spray Process for Cylinder Bores in Automotive Industry
Authors: Barbezat G. , Keller S. , Wuest G. 
Published: May 2021

Abstract
In the Automotive Industry the need for lower manufacturing costs, the use of less strategic material, and easier, faster, and more flexible routes for manufacturing are being looked for continuously. The environmental concerns relating to the use of galvanic coatings is growing. This has led to the examination of the plasma-powder spray process for the application of coatings for surface modification. In the area of engine cylinder bore coatings a major advance is taking place in the use of a rotating plasma spray device. This paper covers the use of a plasma-powder spray process for the coating of aluminum-silicon cylinder block bores using a rotating plasma gun capable of producing coatings of reliable microstructure and integrity. Properties and microstructures of the applied coatings will be presented. Test results will be shown that the necessary bond strength of the coating can be achieved without the use of a bond coat. Surface preparation prior to coating and surface finishing methods after coating will also be discussed. Experience in Europe, Japan and the Unites States will be discussed which show that the plasma-powder spray process offers a performance proven and cost effective solution for the coating of cylinder bores, thus demonstrating the future application potential for this technology.
Component Repair and Chrome Plating Replacement with New Thermal Spray in the United States Navy: Successes and the Future
Authors: Rigney R.W. , Grubowski A. , McCaw R. , Scandell K. 
Published: May 2021

Abstract
High Velocity Oxy-Fuel Thermal Spray has been used by the Navy for repairing components for several years with great success. This paper will discuss some of the applications being done, the results of these applications and where the technology will be utilized on the future. The Office of Naval Research in conjunction with Naval Research Laboratory and Naval Surface Warfare Center is investigating replacements for chrome plating. One of the technologies being looked at is HVOF Thermal Spray. This paper will discuss this program, new materials being developed and new applications being done. The superior physical characteristic of HVOF has increased the utility of this technology from mechanical components to aircraft and submarine components. Acceptance of these coatings at various levels at NAVSEA will be discussed and criteria established for these acceptances will be reviewed. The role of these coatings in ship repairs as well as the implications for new construction will be discussed. Specific examples of repairs will be shown and updated reports will be provided as to their service. Locations that have services available will be detailed and future growth of this technology within the Navy will be reviewed. A quick overview of similar emerging technologies will be provided. A highlight of the presentation will be an update of the repair done with HVOF Tungsten Carbide on the Rudder Rams on the USS Saipan.
The Development and Implementation of Thermal Spray Coatings for Helicopter Components
Authors: Guillemette R. 
Published: May 2021

Abstract
Many components in helicopter dynamics systems depend on hard, wear resistant coatings for reliable performance. Component replacement times are currently limited by performance of these coatings in many cases. Thermal spray coatings have been evaluated for these applications to replace nickel and chromium electroplate. The effect of coatings on fatigue strength is quantified by a strain limit concept to reduce test requirements during development phase. Full scale bench testing and coupon wear testing were conducted to reveal large improvement in sliding and fretting wear resistance. A fine porosity network in thermal spray coatings, high hardness and high fatigue strength are shown to be the main contributors to improved wear performance. Thermal spray coatings also exhibited enhanced corrosion resistance in salt fog and crevice corrosion conditions. These data permitted implementation on several critical helicopter components.
Mechanical Properties of Spray-Formed Composite Structures
Authors: Brogan J.A. , Berndt C.C. , Claudon A. , Coddet C. 
Published: May 2021

Abstract
In this study, ethylene methacrylic acid copolymer (EMAA) was used as the matrix to produce EMAA/Al2O3 and EMAA/NiCr composite coatings from dry-blended powder mixtures. This work was conducted to determine processing concerns when using similar sized reinforcement particles of different density in a flame-spray process. This work has utility for applications that require a reduction in mechanical wear and/or to confer upon a polymeric deposit a certain functional property by the introduction of value-added powder. Free-standing coatings were produced to test the mechanical properties of the sprayed deposit. The effects of the filler content on the secant modulus, yield stress, and tensile strength are discussed. The differences in deposition efficiencies among the EMAA, Al2O3, and NiCr are highlighted with respect to particle size and density.
Oxidation, Thermo-Mechanical, and Novel Lattice-Gas Particle Deposition Modeling Aspects in Plasma Spraying of Ti-6Al-4V/SiC Fiber Composites
Authors: Cochelin E. , Borit F. , Frot G. , Jeandin M. , Decker L. , Jeulin D. , Al Taweel B. , Michaud V. , Noel P. 
Published: May 2021

Abstract
Plasma spraying is known to be one of the main promising processes for the manufacturing of Ti/SiC long fiber composites. However, some improvements remain to be done for this process to be applied in a routine industrial route. These include: oxygen contamination of the sprayed material through that of Ti particles before and during spraying damaging of fibers due to a high level of thermal stresses induced at the spraying stage adequate deposition of Ti-based powder to achieve a low-porosity matrix and good impregnation of the fiber array. This contribution deals with work in the 3 previously mentioned fields, which resulted in a whole 3-fold study of the process. Oxidation was studied using electron microprobe analysis of elementary particles quenched and trapped into a closed box at various given flight distances. Oxygen diffusion phenomena within the particles are discussed from a preliminary theoretical approach coupled with experimental data. Isothermal and thermo-mechanical calculations were made using ABAQUS code to determine stresses arising from contact of a liquid Ti-6Al-4V particle onto a SiC fiber. On a higher scale, i.e. that of the sprayed powder flow, a 2-dimensional original model simulating the deposition of droplets onto a substrate was developed. This model is based on a lattice-gas automaton which reproduces the hydrodynamical behavior of fluids.