bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computer Simulation of Heat Transfer and Phase State Under High–Energy Flux Impact on Solid Body Surface
Authors: Solonenko O.P. , Golovin A.A. 
Published: August 2022

Abstract
A numerical method and software were developed to predict non-stationary conjugated conductive heat transfer, melting and possible evaporation of materials under high energy fluxes impinging onto solid body surface (plasma jet, arc spot, laser or electron beam), and also subsequent cooling and solidification of the melted substrate layer. In the numerical procedure, the finite-element method was employed. The processes of interest can have different characteristic time and spatial scales, which in addition can suffer drastic changes at heat flux densities q ?[108 ;1014 ] W/m2. An advanced procedure was developed to enable dynamic adaptive triangulation of domains involved in the current numerical solution and characterizing the different phase states (liquid or solid) of the materials. This procedure, belonging to the class of the frontal algorithms, allows one to break a solution domain into triangles based only on the domain boundaries. The model applications of the developed simulation software are illustrated.
Impact Modeling of Thermally Sprayed Polymer Particles
Authors: Ivosevic M. , Cairncross R.A. , Knight R. 
Published: August 2022

Abstract
Thermal spray has traditionally been used for depositing metallic, carbide and ceramic coatings, however, it has recently been found that the high kinetic energy of the High Velocity Oxy-Fuel (HVOF) thermal spray process also enables the solventless processing of high melt viscosity polymers, eliminating the need for harmful, volatile organic solvents. A primarily goal of this work was to develop a knowledge base and improved qualitative understanding of the impact behavior of polymeric particles sprayed by the HVOF combustion spray process. Numerical models of particle acceleration, heating and impact deformation during HVOF spraying of polymer particles have been developed. A Volume-of-Fluid (VoF) computational fluid mechanics package, Flow3D®, was used to model the fluid mechanics and heat transfer during particle impacts with a steel substrate. The radial temperature profiles predicted using particle acceleration and heat transfer models were used as initial conditions in Flow3D® together with a temperature-dependent viscosity model to simulate polymer particles with a low temperature, high viscosity core and high temperature, lower viscosity surface. This approach predicted deformed particles exhibiting a large, nearly hemispherical, core within a thin disk, and was consistent with experimental observations of thermally sprayed splats made using an optical microscope.
Observation of Deformation and Microstructure at the Interface Between WC-Co HVOF Sprayed Coating and Carbon Steel Substrate
Authors: Owada A. , Watanabe M. , Kuroda S. 
Published: August 2022

Abstract
The mechanical deformation and microstructure formation at the interface of a high velocity oxygen fuel (HVOF) sprayed WC-Co splat on a carbon steel (0.45%C) have been studied by the focused ion beam (FIB) cross-sectioning and examined by scanning electron microscopy (SEM). Several types of WC-12wt.%Co powders with different WC particle sizes, 0.2 ~ 7.0µm were used for spraying to investigate the size effect of these WC particles onto the splat morphology and microstructure around the interface. The interface fracture toughness of the coatings made of these powders was evaluated by the pre-notched four-point bending test and the correlation between the splat microstructure and the toughness variation was investigated. The interface fracture toughness of these WC-12%Co coating / carbon steel was evaluated as about 600~1700J/m2. It was revealed that the WC particle size in the original powders has large effects onto the interface adhesion.
Experiences in Education/Training and Qaulification of Thermal Spraying Personnel According International Guidelines and Standards
Authors: Böhme D. , Huber R. , Ohliger-Volmer A. 
Published: August 2022

Abstract
In the field of thermal spraying a lot of things have been and still are happening concerning education and training of personnel. The education and training of thermal sprayers according EWF-Guideline is required frequently in combination of the international standard DIN EN ISO 14918 “Approval Testing of Thermal Sprayers” - especially in the German-language countries. Meanwhile about 13 ETS courses were held at the German Welding Institute. Also interested in the education and training of thermal sprayers are countries like Poland and China. In France thermal spray personnel was educated and trained in a company internal course. Sweden and Norway run ETS courses in cooperation. The EWF education and training course of the ETSS European Thermal Spraying Specialist will be offered by the German Welding Institute in Munich - SLV München - for the nineth time in October 2005. Since about 1993 European Committees of EWF (European Federation of Welding, Joining and Cutting) and CEN (European Committee or Standardization) worked out education and training guidelines and qualification standards of thermal spray supervising personnel and sprayers and established them step by step. The meanwhile created and internationally accepted EWF-education and training guidelines of supervising personnel and thermal spray workers involve also the new ISO standards of the Thermal Spraying Co-ordinator and the Approval Testing of Thermal Sprayers. The ISO personnel qualification and quality management standards result together with the EWF education and training guidelines in a sound QM-system, which meets the increased demands of trade and industry of high quality sprayed coating. Experiences in applying these guidelines and standards are introduced.
Shear Force on Wire Tips in Wire Arc Spraying System
Authors: Pourmousa A. , Montazeri H. , Mostaghimi J. 
Published: August 2022

Abstract
In order to find the size and shape of particle detachments in the wire-arc spraying system, it is required to find the shear force on the electrodes (wire-tips). To solve the gas flow problem, the system was divided into two regions: (1) upstream and (2) downstream of the nozzle exit. In region 1, the axisymmetric turbulent gas flow is numerically solved and compared to its approximate analytical solution. In the second numerical region, which includes the tips of the two wires, shear force on the electrode surfaces is evaluated from the gas flow velocity profile adjacent to the electrodes. The gas flow in these regions is solved using the FLUENT software. Abstract only; no full-text paper available.
Development of a Technique for Hard Coating of Component Parts by Synthesis of Silicon Carbide in Thermal Spray Processes
Authors: Bach Fr.-W. , Möhwald K. , Drößler B. 
Published: August 2022

Abstract
The Goal of this research project is the development of a thermal spray technique for production of layers with high SiC content. Due to its physicochemical characteristics, silicon carbide (SiC) is a material which is particularly well suited as a component of wear-protection layers [1]. In thermal spray, however, silicon carbide can not be processed easily, since it disintegrates and sublimates into the gaseous phase at the prevailing high process temperatures under atmospheric conditions. In this project, SiC-phases of the spray layers are to be in-situ synthesized from silicon and carbon-containing substances during the spray process. Silicon containing solids are to be brought into reaction with carbon-containing solids, liquids and gases. For economic reasons, this technique is aimed at using low-priced basic materials to be processed by flame- and plasma spraying techniques with only slight modifications to existing atmospheric spraying equipment; thus the said SiC coatings might become an alternative to assigned hard material coatings. In this first step the technologic-mechanical potential and thus the feasibility and usability of a yet to develop coating system by different synthesis routes should be evaluated.
Influence of WC-Co Type Thermal Spray Powder Characteristics on HVOF Coating Properties
Authors: Song X. , Liu W. , Cui Y. , Wu C. , He M. 
Published: August 2022

Abstract
With the incoming of HVOF, the coating properties and application extent of WC-Co type have been greatly improved, in the recent years, we found that the characteristics of WC-Co powder has some influence on its coating properties prepared by HVOF. In this paper, study has been prepared on powders made from aboard and Beijing General Research Institute of Mining & Metallurgy properties such as fluidity, aspect, profile of coating SEM and carbon content, also phase structure and properties analysis of HVOF coating has been made. Finally, influence of powder preparing technology and HVOF technology parameters of different powders for coating properties have been described.
Thermal Properties of Continuously Graded Thermal Barrier Coatings Deposited by Supersonic Plasma Spray
Authors: Shikui Z. 
Published: August 2022

Abstract
Continuously graded yttria stabilized ZrO2 /NiCoCrAlY coatings were prepared using a high efficiency supersonic plasma-spray system and the thermal shock properties of the coatings were studied. The specimens were so prepared that the two kinds of powders with different melting point were fed to the different regions of the plasma jet by using two powder feeders. The two powders melted perfectly at the same power, and the overheating of the powder with lower melting point was avoided. In this way, a continuously graded transition layer was obtained. The Results show that the continuous change of the coefficients of thermal expansion and thermal conductivity in the transition layer leads to a excellent thermal shock resistance of the totally 0.9mm thick TBCs. The thermal shock cycles of the specimens which underwent heating by oxygen-acetylene to 1200 C and then quenching into water reached moer than 200.The coatings’ surface was still perfect without any visible cracks. The analysis shows that the dense structure and the sufficient plastic deformation of the particles depressed the formation of TGOs, which, together with the continuously graded thermal expansion coefficient and thermal conduction coefficient, contributes to the long thermal shock resistance of the coatings. Abstract only; no full-text paper available.
High Temperature Characteristics Research of CoCrAlYTa Coating
Authors: Song X.J. 
Published: August 2022

Abstract
High temperature alloy powder CoCrAlYTa made by vacuum-atomized technology has satisfied properties such as spherical degree, fluidity and low oxygen quantity etc. Compact and steady high temperature properties coating was prepared when CoCrAlYTa was blast sprayed onto stainless steel. In this paper, several high temperature working performance like hot shocking, high temperature oxidation and high temperature corrosion of CoCrAlYTa coating got was studied, the micro-structure of coating was analyzed with metallographical analysis, SEM and XRD. Experiments results indicated that, with the added of Y and Ta, the structure and toughness of chromium and aluminum oxidation membrane in the coating was improved, overall, blast spraying coating has excellent high temperature characteristics. Abstract only; no full-text paper available.
Alumina-Titania Coatings Deposited by Laser-Assisted Air Plasma Spraying: Microstructure and Mechanical Characterization
Authors: Dubourg L. , Lima R.S. , Moreau C. 
Published: August 2022

Abstract
Alumina-titania coatings deposited by air plasma spraying (APS) are widely used to protect components against wear at low temperatures. It is known that microstructures formed by the post-laser remelting of as-sprayed coatings exhibit a densification but also numerous macrocracks due to the rapid cooling and thermal stresses. By using the laser-assisted air plasma spraying (LAAPS), the laser beam interacts simultaneously with the plasma torch in order to increase coating surface temperature and possibly superficially remelt the coating. As a result, the microstructure is partially densified and macrocracks, which are generally produced in the post-laser irradiation treatment, can be inhibited. In addition, this hybrid spraying can be done without the post-treatment of coating. In this paper, LAAPS was performed to improve the mechanical properties of Al2O3-13%TiO2 coatings. The coating microstructure was characterized by SEM and X-ray diffraction. The mechanical characterization was done by hardness measurements, erosive wear tests and abrasion wear tests. Results showed that laser assistance may induce: (1) the disappearance of vertical and horizontal macrocracks due the laser irradiation in the coatings for a laser irradiation density lower than 34 W.mm-2, (2) an important decrease of the amount of microcracks in the deposited splats, (3) the partial transformation of the metastable γ-Al2O3 phase in the equilibrium α-Al2O3 phase, (4) a hardness increase of 11%, (5) an improvement of the erosive wear resistance by 12% and (6) an improvement of the abrasive wear resistance by 38%.
Research on the Coating Performance Produced by Arc Spraying using High Velocity High Energy Combustion Gas
Authors: Huang X. , Wang R. , Zhang T. , Xu L. 
Published: August 2022

Abstract
In this paper describes the design of the arc spray gun with secondary atomization, which using the mixture of propane and air as the main gas and the compressed air as the gas for secondary atomization. The test shows that in the high velocity airflow produced by the combustion of propane – air mixture, the atomized particle size is less than 20 micron. In the second- combustion thermal airflow, the high temperature area of the arc beam is obviously lengthened at the same time the combustion gas environment restrains the oxidation of the spraying materials. Because the speeds of particles are improved greatly, the coatings obtained are denser. Through practical application it shows that this system can obtain stable deposition efficiency, high bond strength, and low roughness and greatly reduce the cost of machining. Abstract only; no full-text paper available.
Correlation of Plasma Process Conditions, Phase Content, and Photocatalytic Performance of Induction Plasma-Sprayed Titania Coatings
Authors: Burlacov I. , Heimann R.B. , Müller M. 
Published: August 2022

Abstract
Systematic variation of the induction plasma spray (IPS) conditions, i.e. (i) plasma power, (ii) carrier gas flow rate, and (iii) powder feed rate was performed to deposit TiO2 coatings using statistical design of experiments (SDE) methodology. The microstructure, surface morphology, and anatase-rutile ratio of the coatings were studied by grazing-incidence X-ray diffraction (GIXD) and surface mapping with micro-probe Raman spectroscopy to determine the spatial phase distribution of anatase and rutile. The photocatalytic activity of the TiO2 coatings was tested by decomposition of 4-chlorophenol in aqueous solution in the dark and under UV irradiation. The rates of pH changes measured were compared with those of standard Degussa P-25 coatings. The photocatalytic activity of the samples shows a reasonable correlation with the phase content and the plasma processing conditions prevailing during coating deposition.
Development of Gas-Tight Zirconia Electrolyte Layers by Atmospheric Plasma-Spraying
Authors: Vaßen R. , Hathiramani D. , Stöver D. 
Published: August 2022

Abstract
Atmospheric plasma-spraying (APS) is an attractive process for the production of solid oxide fuel cell layers. However, especially the manufacture of gas-tight electrolyte layers is a major challenge as typical APS ceramic coatings contain microcracks and pores which allow an easy penetration of gases. To overcome this problem a detailed understanding of the formation of microcracks and pores in the coating was developed. These ideas and the conclusions made will be described in detail. Major influencing factors were identified to be substrate temperature, particles temperature and velocity, particle size, and the way the plasma gun is moved. According to the outcome of these considerations spraying experiments have been performed with different yttria stabilized zirconia (YSZ) powders including spray dried and fused and crushed types. Porous, tape-casted metallic plates were used as substrates. Employed measures for the coating optimization lead to a significant reduction of both length and opening of the microcracks. These results were in accordance with the outcome of leakage tests. It was possible to improve the leakage rates by several orders of magnitude and to achieve sufficiently low values for an application as solid oxide fuel cell electrolyte without any subsequent thermal treatment.
Effective Laser-Cladding through the Application of Magnetic Induced Forces
Authors: Wilden J. , Bergmann J.P. , Dolles M. 
Published: August 2022

Abstract
In the last years laser beam cladding was recognised as a high quality coating process. Low thermal influence, high cooling rates, metallic bonding, minimal surface roughness are only some of the positive aspects. On the other hand the process efficiency is very low and the running costs in comparison to PTA or Thermal Spraying are high. Attempts to improve the productivity aim to enhance the efficiency of the beam source itself or to optimize the energy management. This is for example possible through a higher coating speed or through hybrid setups, which allow the use of an additional preheat source (e. g. plasma-assisted laser cladding). Regarding flexibility, defined as the capability of a process to answer in a short time to application requests, the effectiveness of laser cladding can be widely increased through free forming (shaping) of coatings without additional clamping devices. The geometric shape of the coating seam is mainly defined by gravity and surface tension of the melt. An additional force, as for example Lorentz force, can optimize the geometry and improve the process conditions. Wide seams allow for example a low number of overlapping layers when coating large areas and rise the specific area deposition rate. Slim coatings on the contrary are advantageous when generating 3-dimensional structures. The induced force depends from the applied magnetic field and the flow of an electric current. The presented investigations clarify the physical background, the interaction of the magnetic force and the geometric shape of the coating and the possibility to apply them for technical coatings. The application of an external force made it possible to increase the efficiency of the laser cladding process and to gain more interest of the industry.
Improved Process Controls of Combustion Sprayed Clearance Control Coatings Through Sensor Diagnostic Technology
Authors: Fiala P. , Hajmrle K. , Dorfman M.R. , Dambra C. , Mallon J. 
Published: August 2022

Abstract
Sensor technology is becoming more of a production tool to help improve production quality, reliability and reduce manufacturing costs. Combustion sprayed abradable seal products are a family of materials where this technology will be helpful to the applicator and end user. Although these materials have been used for over forty years with wide success in the aerospace and industrial gas turbine industries they can be sensitive to spray process variables. Changes in spray processing conditions during spraying will change the desired microstructure and coating properties. This paper looks at a commercially available combustion powder and how process parameters such as gas flows and powder feed rates affect output process variables such as particle velocity and temperature. This paper will also discuss the importance of understanding the influences that particle temperature and velocity have on coating properties such as hardness, erosion and coating strength. Deposit efficiency of these combustion powders is also measured as a function of particle temperature and velocity. Based on particle temperature and velocity, sensor diagnostic tools can provide warnings about process changes resulting in fast corrective action. The benefits of this sensor technology are the potential for less inspection requirements, improved microstructure control, reduced in-service failures, and less time and labour required for stripping coated components that may not meet specification standards.
Influence of Reflected Radiations on in Flight Particle Temperature Measurements
Authors: Klein D. , Salhi Z. , Coddet C. 
Published: August 2022

Abstract
Characteristics of in flight particles before they impact on the substrate influence strongly the quality of coating obtained by plasma spraying. Various optical techniques can be used to measure the in-flight particle characteristics; some of these techniques require the use of high- speed two-color pyrometers to collect the light emitted by the particle during the in-flight period when they pass through the measurement volume. However, the intense radiation coming from the plasma can affect the particle thermal radiation and lead to erroneous measurements. This work was dedicated to the study of reflected light coming from the plasma and scattered by the injected particles. To achieve this goal, sprayed particles were analyzed by optical emission spectrometry. The light scattered by the particles was found to influence significantly the measured temperature. This work allows thus the estimation of the accuracy of temperature measurements on particle surface for the thermal spraying process. Abstract only; no full-text paper available.
Transient Thermal Analysis and Coating Formation Simulation of Arc Spray Process
Authors: Zhu Y. , Liao H. , Coddet C. 
Published: August 2022

Abstract
A finite difference model for the thermal analysis of the dynamic stochastic multiple particle deposition process of thermal spray was developed in this paper. Contrary to the traditional layer by layer deposition model, the thermal contribution of individual particles randomly distributed around the spray jet center was taken into account so as to simulate coating formation process. New material was dynamically added onto coating/substrate surface with prescribed gun movement. Latent heat effect was introduced by defining the enthalpy of the material as a function of temperature in order to take into account solidification induced phase change. Real thermal spray process can be simulated with adjustable particle size, spray deposition rate, velocity of gun movement, etc.
Residual Grit on the Substrate Surface in Roughening Treatment: Quantitative Evaluation and a Reduction Technique
Authors: Maruyama T. , Kobayashi T. , Tsujimoto K. , Tani K. , Tanaka K. 
Published: August 2022

Abstract
Generally, the surface of a substrate is roughened by blasting in pretreatment thermal spraying. Since some of the grit remains on the substrate surface, sprayed coating and the adhesion property characteristics are degraded. However, it seems that there is almost no research on this problem. In this study, residual grit is quantitatively evaluated, and a technique for reducing grit is proposed. For residual grit reduction, a solid lubricant was used, and applied to the surface of a substrate or grit; reduction of residual grit was confirmed. After blasting with solid lubricant, it remained on the substrate surface, which could be removed by heating the substrate.