bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructure and Mechanical Properties of 7075 Al Matrix SiC Reinforced Composite Coatings Produced by the Cold Gas Dynamic Spraying Process
Authors: Meydanoglu O. , Jodoin B. , Sabri Kayali E. 
Published: November 2022

Abstract
Microstructure and mechanical properties of 7075 Al alloy matrix and SiC reinforced composite coatings deposited on a T6 6061 Al alloy by cold spray are investigated. Feedstocks are prepared as mixtures of 7075 Al alloy and SiC powders with SiC content varying between 0 to 40 vol. %. Microstructural characterization is carried out by optical and scanning electron microscopic examinations and X-ray diffraction (XRD) analysis. The coatings mechanical behavior is evaluated using hardness measurements and wear tests. Wear tests are conducted under dry conditions using a ball-on disc tester under atmospheric conditions. The presence of SiC improves the coatings hardness and wear resistance when compared to pure 7075 Al coatings. The coating hardness increases with increasing SiC content; however SiC content higher than 10 vol.% does not lead to further increase in wear resistance. In this respect, the optimum composition of the coating is determined to be 92 vol. % 7075 Al + 8 vol. % SiC.
Application of Structure-Based Models of Mechanical and Thermal Properties on Plasma Sprayed Coatings
Authors: Vilémová M. , Matějíček J. , Mušálek R. 
Published: November 2022

Abstract
Mechanical and thermal properties of thermally sprayed coatings, especially ceramics, are strongly influenced by cracks and pores that are present in the coating microstructure. In the recent past, there have been efforts to find an analytical model describing the coating properties based on the microstructural characteristics. Various analytical models were developed and published in the literature. In this study, several major models were applied to ceramic and metal coatings to describe their elastic modulus and thermal conductivity. The sensitivity of the models to the variations in the microstructure and relevancy of their use in specific cases were examined. The results were compared with those obtained by FEM modeling and experimentally measured values.
Heat and Mass Transfer within an Evaporating Solution Droplet in a Plasma Jet
Authors: Hu Y. , Shan Y. 
Published: November 2022

Abstract
A mathematical model is developed to analyze thermo-physical phenomenon within an individual solution precursor droplet travelling in the high temperature plasma jet. The model involves the motion and evaporation of the droplet and the heat and mass transfer within the droplet. The influence of Stefan flow and the variable physical properties of the environment gas around the droplet are considered. The internal circulation due to the relative velocity between the droplet and the plasma jet, which can be described by the Hill’s spherical vortex, is considered as well. The trajectory, temporal droplet surface temperature and radius variation are predicted. The temperature and concentration distribution inside the droplet as well as the difference between the droplets with different injection parameters are presented.
Homogenization of Coating Properties in Atmospheric Plasma Spraying – Results and Outlook of a DFG (German Research Foundation)-Funded Research Group
Authors: Bobzin K. , Schläfer T. , Petković I. , Hartz-Behrend K. , Landes K. , Forster G. , Kirner S. , Marqués J.-L. , Zimmermann S. , Schein J. , Prehm J. , Xin L. , Erne M. , Möhwald K. , Bach Fr.-W. 
Published: November 2022

Abstract
The goal of this research group is to homogenize properties of three-cathode plasma sprayed coatings on basis of numerical simulations and advanced diagnostics. Results of the first project phase as well as an outlook to future work are presented. A numerical model for investigation of plasma flow in the free jet, produced by three-cathode torch was developed. Modelling results are verified by plasma diagnostics (Computer Tomography). In order to include particle shrinking effects, coating formation simulation is accomplished by a newly developed model, based on Computational Fluid Dynamics coupled with the Finite Element method, whereat diagnostics carried out in the fields of particle diagnostics. During the next phase of the project, the investigation of the plasma free jet and particle injection by advanced diagnostics and simulation respectively is scheduled. In a subsequent stage the transition from conventional particles to suspensions will be considered. Coating formation simulations are scaled up to dimensions of macroscopic tensile tests. By combining these overarching investigations, appropriate process parameters for homogenized coatings will be obtained.
Titanium Dioxide Coatings Sprayed by a Water Stabilized Plasma Gun (WSP) With Argon and Nitrogen as the Powder Feeding Gas: Differences in Structural, Mechanical and Photocatalytic Behavior
Authors: Ctibor P. , Pala Z. , Neufuss K. , Štengl V. , Píš I. , Zahoranová T. , Nehasil V. 
Published: November 2022

Abstract
Titanium dioxide coatings were sprayed by a water stabilized plasma gun (WSP) to form robust self-supporting bodies with a photocatalytically active surface. Agglomerated nanometric powder was used as a feedstock. In one case argon was used as a powder-feeding as well as coating-cooling gas whereas in the other case nitrogen was used. Stainless steel was used as a substrate and the coatings were released after the cooling. Over one millimeter thick self-supporting bodies were studied by XRD, HR-TEM, XPS, Raman spectroscopy, UV-VIS spectrophotometry and photocatalytic tests. Majority of the tests was done at the surface as well as at the bottom side representing the contact surface with the substrate during the spray process. Porosity was studied by image analysis on polished cross sections where also microhardness was measured. Dominant phase present in the sprayed samples was rutile whereas anatase was the main minor component. Hydrogen content in the nitrogen assisted coating was higher, but the character of the optical absorption edge remained the same for both samples. Photoelectron spectroscopy revealed differences in the character of O 1s peak between both samples. The photocatalytic activity was tested by decomposition of acetone at UV illumination, whereas also the end products - CO and CO2 - were monitored. The nitrogen-assisted coating was revealed as more efficient photocatalyst.
Oxidation Behaviour of CoNiCrAlY Bond Coats Produced by APS, HVOF and CGDS at Temperatures of 1000 °C and 1100 °C
Authors: Roy J.-M. , Richer P. , Beauvais L. , Jodoin B. 
Published: November 2022

Abstract
This work compares the oxidation behaviour of CoNiCrAlY coatings manufactured by the HVOF, APS and CGDS processes when submitted to temperatures of 1000°C and 1100°C. The as-sprayed coating microstructural features were characterised using SEM and XRD analysis before being subjected to isothermal heat treatments in an air furnace. Oxide scale composition was determined using XRD, SEM and EDS analysis while the oxide growth rates were obtained using mass gain measurements. The as-sprayed HVOF and CGDS coatings exhibit similar microstructures while the APS samples have a significantly higher porosity and oxide content levels. Results from the oxidation experiments indicated that the oxide growth rate of HVOF and CGDS were lower than that of the APS samples. The results also indicated that samples oxidised at 1100°C have a lower oxide growth rate than those oxidised at 1000°C. Analysis of the oxidation process up to 100 hours indicates that the formation of dense α-Al2O3 is more favourable at 1100°C while a transition alumina, θ-Al2O3 is more favourable at 1000°C. Furthermore, the surface profile of the samples oxidised at 1100°C were more uniform and free of protrusions.
Biocompatibility of Titanium Coatings Deposits on CoCr by Cold Spray
Authors: Trentin A. , Vezzù S. , Rech S. , Gulizia S. , Jahedi M. 
Published: November 2022

Abstract
The excellent corrosion resistance and biocompatibility of titanium make of it the material to choose for biomedical applications. Cold spraying, as a new coating technique, can be used to deposit protective Ti coatings onto less performing materials such as stainless steel and Co-Cr alloys, commonly used for biomedical implants. In addition, Cold Spray has the advantage, in comparison with conventional thermal spray techniques, to permit the deposition of oxygen-sensitive materials. In this study, Cold Sprayed Ti coatings were prepared on Co-Cr alloy substrates by using different spray process conditions. The microstructure of coatings was observed by SEM and the inner porosity was estimated by image analysis. Oxygen and nitrogen contents were investigated on a set of free standing deposits obtained using different process parameters. In the same way, the roughness and microhardness of deposits, such as the adhesion strength with the substrate, were measured. Finally, the corrosion performance of the coatings was evaluated by mean of open circuit potential measurement (OCP) and potentiodynamic polarizations scans. The electrochemical response was therefore discussed and compared to the corrosion behaviour of the Co-Cr alloy substrate and the bulk Titanium.
Measurement of Specific Enthalpy under Very Low Pressure Plasma Spray Condition
Authors: Zhang N. , Sun F. , Zhu L. , Planche M. P. , Liao H. , Dong C. , Coddet C. 
Published: November 2022

Abstract
Very low pressure plasma spraying has been intensively studied in recent years especially the properties of plasma jet. These properties are affected by plasma generating and working conditions. These operating parameters such as arc power, plasma gas flow rate and chamber pressure have influences on specific enthalpy and temperature of plasma jet. In this work, the measurements under very low pressure were performed using enthalpy probe which was previously modified (increase of the internal diameter and depositing TBC coating (Ni/Al and ZrO2+ Y2O3) on the head). Different parameters, for instance, current intensity, hydrogen gas flow rate and detecting distance were changed in order to point out their effect on the characteristics of plasma jet. The specific enthalpy, temperature and quantity of heat in this situation were obtained.
Development and Characterization of Oxide Ceramic APS Coatings for Microwave Absorption
Authors: Müller P. , Floristán M. , Killinger A. , Gadow R. , Cardella A. , Li C. 
Published: November 2022

Abstract
Thermonuclear fusion is a promising source of clean energy for the future. Max-Planck-Institute für Plasmaphysik (IPP, Greifswald, Germany) is currently working on the new type of fusion reactor, the stellarator Wendelstein 7-X. The extreme operating conditions of fusion reactor devices have lead to an increasing interest in the field of high performance materials. The present work describes the development of coating systems acting as efficient absorbers for 140 GHz radiation, which is the microwave frequency to which the analyzed components of Wendelstein 7-X are subjected. Several types of oxide ceramic coatings were applied by Atmospheric Plasma Spraying. Different powders were used as feedstock material for the coating operation. The influence of the process parameters on the coating properties and microwave absorbing capability was analyzed. The coatings microstructure and mechanical properties were characterized in terms of porosity, microhardness, roughness, adhesion and residual stresses. XRD and SEM were carried out. It was found that thickness and microstructure of the coatings have a significant influence on microwave absorption behavior. For Al2O3/TiO2 coatings, absorption values over 90% were obtained. After optimization of the coating structure, the coating process was adapted to several real reactor components that will work in Wendelstein 7-X.
Cavitation Erosion Mechanism in Fe-Mn-Cr-Si-Ni Arc Thermally Sprayed Coatings
Authors: Pukasiewicz A. G. M. , Capra A. R. , Paredes R. S. C. 
Published: November 2022

Abstract
Cavitation erosion is a common phenomenon that occurs in hydraulic turbine blades and result in mass loss. Welding is the most common technique used to recover the geometrical profile of these cavitation eroded turbine blades, however it is known that tensile residual stress can develop. The development of manufacture process that could reduce or eliminate the residual stress level will contribute for a longer service life of this component. It is aimed in this study evaluate cavitation erosion mechanism of Fe- Mn-Cr-Si-Ni arc thermally sprayed coating. Coatings were analyzed by optical and scanning electronic microscopy, microhardness, cavitation tests (ASTMG32-92) and the analysis of eroded surface areas after ultrasonic cavitation tests with DRX and SEM. The results showed that lamellae morphology, oxide volume fraction and porosity modified by changings in parameters deposition, modified cavitation mass loss mechanisms. After ultrasonic cavitation tests, it was verified that mass loss occurred by interlamellae oxide removal and splats surface deformation in initial stages, followed by rupture and finally detachment of the lamellae. Splashing droplets promote greater mass loss in some localized areas because they lower intersplat cohesion.
Thermal Barrier Coatings on Novel High Temperature Cobalt Rhenium Substrates
Authors: Seiler P. , Rösler J. , Mukherji D. , Kopka T. 
Published: November 2022

Abstract
Presently, highly stressed components in gas turbines are mainly made of single crystal nickel based alloys and the maximum application temperature (without coatings) is typically limited to 1100°C. Superalloys are now reaching limits posed by their melting temperatures. Increasing the substrate temperature beyond 1200°C will increase the efficiency of the turbine significantly. A new generation high temperature Co-Re alloys are aimed for use at +100°C above present single crystal nickel-superalloys. The substrates will be protected against the higher gas temperatures by thermal barrier coatings. For Co-Re alloy substrates CoReCrSi is a promising bond-coat material. CoReCrSi is thermo-chemically compatible to Co-Re due to the very similar mechanical and chemical properties. The oxide formation and the adhesion of the top coat are being investigated by studying a simplified coating system. The coating system consists of a CoReCrSi bond coat bulk material, and an yttria-stabilised zirconia top coat. The system was tested under cyclic conditions at 1200°C. This study provides a first insight into the TGO growth, the basic failure mechanism of the top coat, and the diffusion processes at the top coat/bond coat interface. It is shown that CoReCrSi with 2 at.% silicon promotes a good adhesion of the top coat by forming a dense chromium oxide layer. The critical TGO thickness beyond which the TGO fails by spallation was determined to be 25 microns and is roughly 2.5 times the critical thickness in MCrAlY based system in nickel-alloys.
Advanced Thermal Barrier Coatings from Ti-Doped YSZ Systems
Authors: Jarligo M. O. , Mauer G. , Mack D. , Vassen R. , Stöver D. 
Published: November 2022

Abstract
Fracture toughness and phase stability are crucial properties of thermal barrier coatings (TBC) during highly loaded thermomechanical operations in gas turbines. While several alternative TBC materials have exhibited excellent thermal resistance, their potential applicability has been limited due to poor endurance to cyclic stresses. The addition of TiO2 to the non-transformable tetragonal t´-YSZ has been found to effectively enhance the fracture toughness and phase stability of YSZ at high temperature exposures. Thermal cycling tests in a burner rig were conducted on TBCs prepared from atmospheric plasma sprayed titania-doped YSZ to verify this phenomena. Exposure temperature was 1400°C at the surface and thermal gradient across the sample was provided by simultaneous back-cooling treatment. Cycling tests reveal that the slight increase in the tetragonality of the deposited coatings with increasing amount of dopant did not cause a significant effect to the lifetime of the TBCs. Moreover, increasing amount of Ti-substitution did not influence the fracture toughness of the bulk YSZ.
Scratch Test Mechanical Properties of Suspension Plasma Sprayed TiO2 Coatings
Authors: Łatka L. , Pawłowski L. , Petit F. , Kozerski S. 
Published: November 2022

Abstract
Titanium oxide coatings were suspension plasma sprayed onto different substrates. The suspension was formulated using fine rutile pigment in the mixture of water with ethanol. The zeta potential of the suspension was determined. The spray process parameters were designed using a full factorial plan using spray distance and torch scan velocity as the variables. The temperature at spray process was monitored using a pyrometer. The X-ray diffraction (XRD) analysis enabled to find out the crystalline phases in sprayed deposits and, in particular, the anatase content. Scanning electron microscope (SEM) enabled to characterize the coatings’ microstructure. The coatings included well molten lamellas and zones of loosely agglomerated and sintered grains. The scratch test of the coatings enabled to determine their mechanical properties such as critical load and scratch hardness.
Characterization of Detonation Sprayed Coatings
Authors: Shtertser A. A. , Ulianitsky V. Yu. , Tsarakhov K. A. , Grinberg B. E. 
Published: November 2022

Abstract
Characterization of coatings made with the help of Computer Controlled Detonation Spraying (CCDS) was performed. The applied coatings include hard alloys (WC/Co -75/25, WC/Co - 88/12, WC/Co/Cr - 86/10/4, and Cr2C3 / NiCr), aluminum oxide, nickel-chromium self-fluxing alloy, titanium, bronze, and stainless steel. Tribological investigations of coatings were provided using abrasion test (ASTM standard G65), erosion test (ASTM standard G76), and hydro-abrasive test. To make hydro-abrasive tests special device and method were elaborated based on the interaction of water jet saturated with corundum particles with a coating surface.
Impact Particle Behavior in Cold Gas Dynamic Spray of Composite Coatings
Authors: Leshchynsky V. , Papyrin A. , Bielousova O. , Yadroitsava I. , Smurov I. 
Published: November 2022

Abstract
The cold gas dynamic spray process offers a unique advantage to form composite coatings by applying powder mixtures. The powder mixture constituents are supposed to interact with each other during impact. In this study, Al and Cu-based powder mixtures are used with the aim to define specific features of the coating formation. Composite coatings with different Al2O3, SiC, and Ti content are sprayed. Impact behavior of various powder mixtures is analyzed based on scanning electron microscopy images. The Al2O3 and SiC phases of the initial powder are found to be fractured on impact and preserved in the coatings. Another advantage of the kinetic spray process is the ability to mix materials which would normally react with each other and form a composite coating. Some experimental data of such reactions are discussed. Within the composite coating, each constituent changes the initial properties of the sprayed powder material: for example, the soft matrix is strengthened, and hard particles are fractured. The fracture and deformation behavior of the particles and their reactions induced by the impact are determined by micromechanical tests and EDX analysis. Morphology, physical and mechanical properties of the sprayed coatings are discussed.
Novel Manufacturing Method for Producing Stacked Wire Mesh Compact Heat Exchangers Using Cold Spray
Authors: Assaad J. , Corbeil A. , Richer P. , Jodoin B. 
Published: November 2022

Abstract
Heat exchangers play a vital role in ongoing efforts to conserve energy. Plate-type heat exchangers typically consist of two flat separated flow paths in which heat transfer enhancing matrices are inserted. The combined effects of small irregular hydraulic diameters along with elevated heat transfer areas results in highly-efficient heat transfer to the external fluid. This allows for very versatile and compact heat exchanger designs. Typical plate-type heat exchanger fabrication methods such as brazing are labour intensive and limit post-processing operations like welding. In this paper, a novel micro-heat exchanger fabrication method using recently patented technologies is presented. The approach uses thermal spray processes such as Pulsed Gas Dynamic Spraying (PGDS) as an alternative to brazing for the production of a pressure barrier and integration of flow headers. Mesh wafer surfaces sealed using PGDS
New Cold Spray Based Technique of FeAl Intermetallic Compound Coating Synthesis
Authors: Maev R. Gr. , Leshchinsky E. , Maeva E. 
Published: November 2022

Abstract
The FeAl intermetallic compound offers a combination of attractive properties such as thermal barrier, good strength at intermediate temperatures and an excellent corrosion resistance at elevated temperatures under oxidizing, carburizing and sulfidizing atmospheres. So they have attracted considerable attention as potential candidates for structural and coatings applications at elevated temperatures. However, the application of these intermetallics has been limited due to lack of deposition techniques and their low ductility at room temperature. To overcome the drawbacks we apply Low Pressure Cold Spray (LPCS) with following sintering for improving coating ductility and structure. The aim of this paper is to present the first results of FeAl intermetallic compound synthesis with this technique. A CS deposit is built up by the successive impact of individual powder particles that are the ‘‘building blocks’’ of the deposit. Sintering is applied to utilize reactions between the particles and obtain complex intermetallic compound. The microstructures and properties of the coatings were characterized by SEM, EDX and thermal diffusivity tests to define the structure formation mechanisms.
Automatic Generation of Robot Trajectory for Free-form Surfaces in Thermal Spraying
Authors: Fang D. , Deng S. , Liao H. , Coddet C. 
Published: November 2022

Abstract
Automatic robot trajectory generation for thermal spray applications is considered necessary for advanced automatic manufacturing. Achieving coating uniformity on the free-form surfaces is the principal challenge due to the complexity of their geometries. The purpose of this study is to develop a new function of Thermal Spray Toolkit with user-friendly interface for automatic generation of robot trajectory on the irregular workpieces according to the spray parameters, such as the torch speed, the spray distance, the spray angle, etc. This software toolkit is based on RobotStudio which is an off-line programming and simulation software by ABB company. The results showed that the robot trajectories can be generated rapidly, accurately and automatically on the free-form surfaces by using Thermal Spray Toolkit.