bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxide Characterization of Copper Cold Spray Feedstock Powders with X-Ray Photoelectron Spectroscopy
Authors: Katsari Christina Maria , Kotsakis Yannis , Yue Stephen , Guerreiro Bruno , Poirier Dominique , Giallonardo Jason D. 
Published: May 2023

Abstract
In conventional powder processing, there has been considerable work on classifying feedstock powders based on particle size distribution, morphology, microstructure and composition, since these influence processability and final properties. Cold spray is a new application for powders and conventional characterization may be insufficient to assess powder cold sprayability. In particular, metallic powders have an oxide layer, which breaks during impact with the substrate or with another coating layer during cold spray; this fragmentation facilitates bonding. It has been suggested that the thickness of the oxide layer can influence the mechanism of fragmentation; thicker oxides are easier to remove, revealing clean metal surfaces that can metallurgically bond. Consequently, not all high-purity powders or powders that are stored in ambient conditions have the potential to give good coating properties after cold-spray. This work focuses on surface oxidation of the powders, characterizing the variation of oxide film aspects with size and composition of nominally pure copper powders using X-ray Photoelectron Spectroscopy (XPS). The results indicate the presence of Cu (I) and Cu (II) oxide species on the surface of as-received, naturally aged and heat-treated powders; their thickness is determined using the depth profiling feature.
Comparative Study of Ni-, Co- and Fe-Based Laser Cladding Coatings for Wear and Corrosion Resistance
Authors: Larouche Bernard , Hepp Rolf , Reisel Guido , Fiala Petr 
Published: May 2023

Abstract
Among hardfacing processes using welding, laser cladding is nowadays one of the most efficient surface coating techniques. It is widely used to increase wear and corrosion resistance of machine parts as a result of the unique process characteristics such as low heat input (smaller heat affected zone), distortion free clad layers, lower dilution rate, finer coating microstructure as well as good metallurgical bonding at the coating/substrate interface. A wide range of new hardfacing materials and corrosion-resistant alloys are available on the market and in this study, different coatings of Ni-, Co- and Fe-based alloys as well as carbide-based metal matrix composites have been deposited by laser cladding for benchmarking purposes. Coatings were deposited onto mild steel substrates using a high-power diode laser. Coating microstructure and hardness were investigated as well as their tribological properties such as 2-body and 3-body abrasion, slurry abrasion and cavitation erosion resistance. Corrosion performance of coatings was also investigated with the salt spray test. Coatings are ranked according to their performance in the different tests and relationships between microstructure and coating properties are discussed.
Influence of Nozzle Diameter on Electric Arc Dynamics in a Cascaded-Anode Plasma Torch
Authors: Ruelle Céline , Goutier Simon , Rat Vincent , Kéromnés Alan , Rivaud Geoffroy , Chazelas Christophe , Meillot Érick 
Published: May 2023

Abstract
Electric arc dynamics in plasma torch affects plasma jet stability and consequently, coating properties. Depending on plasma torch design, voltage fluctuations can vary from 100 % to only a few percent of the mean voltage. Particularly, cascaded-anode plasma torch leads to very low voltage fluctuation owing to the presence of neutrodes that limit the amplitude of arc fluctuations. However, electric arc dynamics and electrode erosion process in this type of plasma torch are still poorly understood. The aim of this work is to deepen the knowledge on the influence of nozzle diameter on electric arc dynamics for two plasma forming gas compositions by means of several diagnostics devices (end-on imaging, current and voltage time monitoring, plasma jet brightness fluctuations and thermal balance determination). Reducing nozzle diameter from 9 mm to 6.5 mm results in higher voltage fluctuations, lower mean voltage and lower plasma torch thermal efficiency, probably due to a more evenly distributed warm plasma gas in the anode nozzle volume, as suggested by the higher plasma brightness. Nozzle observations after testing show significant wear in a 6.5 mm diameter nozzle, which may be evidence of a longitudinal movement of the electric arc on the anode surface, leading to high voltage fluctuations.
A Novel Approach to In Situ Coating Thickness Measurements in Thermal Spraying
Authors: Hudomalj Uroš , Sichani Ehsan Fallahi , Weiss Lukas , Nabavi Majid , Wegener Konrad 
Published: May 2023

Abstract
Coating thickness is considered to be one of the most important characteristics of thermally sprayed coatings. Despite this, there is a lack of a measurement method that could evaluate in situ the coating thickness with a sufficient accuracy that could be used as a feedback signal for online, closed-loop control. Offline methods that produce spatially resolved coating thickness measurements by capturing the surface topography have already been demonstrated to provide results with a high accuracy, comparable to the standard reference microscopical measurement method. However, up to now, the approach has not been applied in situ. This paper presents a novel approach to in situ measure spatially resolved coating thickness. It is based on a differential distance measurement of sample thickness before and after applying the coating. A high-resolution 3D camera is used to capture the surface topography and include it in the thickness measurement. The technique provides a 3D view of the deposited coating thickness measured in situ and gives results with excellent accuracy when compared to the reference microscopical method.
Towards a General Cold Spray Additive Manufacturing Framework for Fabricating Complex Structural Components
Authors: Li Wenbo , Wu Hongjian , Shi Zhoukun , Liao Hanlin , Costil Sophie , Deng Sihao 
Published: May 2023

Abstract
As an emerging additive manufacturing method, cold spray additive manufacturing (CSAM) has attracted more and more researchers’ attention due to its unique advantages. However, only a few researchers have studied the fabrication of complex structural components. Therefore, it is important to develop a general CSAM framework that is suitable for the fabrication of different shapes of workpieces. In particular, the choice for the optimal kinematic spraying parameters, the prediction of deposit evolution and the planning of spraying trajectory are the most basic and crucial. Different sub-modules are integrated in the proposed framework to solve these problems. In detail, the modeling methodology is used to obtain the optimal kinematic spraying parameters and to predict the deposit evolution in the simulation. Based on the feasible parameters, the trajectory planification methodology is used to generate the spraying trajectory for the workpiece being manufactured, especially the workpiece with complex structure. Finally, the simulation and experimental results of a fabrication for a workpiece with complex structure provide the developed system is reliable and effective. The framework developed in this paper can considered as a general tool for additive manufacturing of with complex structural workpieces in the CSAM.
Property Characterization of Al1050 Bulk Cold Spray Deposits and Numerical Study of Thermomechanical Effects during the Additive Growth
Authors: Sokore Mohamed , Deng Sihao , Liao Hanlin , Raoelison Rija Nrina , Gao Shuohong 
Published: May 2023

Abstract
Cold Spraying is an emerging additive manufacturing method that uses a high-speed collision of micrometre sized powders capable of producing a solid-state bonding. Such a principle has led to the recent development of a coating for various surface functionalization and additive manufacturing applications. This paper is the result of an experimental study on the evolution of the deposit properties (ultimate strength, and porosity) generated by the additive growth during cold spraying. The deposit characterization shows the existence of ultimate strength gradient. For samples taken from the bottom to the top of the deposit, the ultimate strength decreases but there is no significant change in porosity value. The porosity evolutions do not allow to establish a generalized law of variation. The numerical analysis of the additive growth shows that the thermomechanical response of the stacking powder during the additive growth can decrease the bonding capacity, the thermomechanical heating (due to the plastic work) and the gradient of thermal kinetics.
Mixed-Material Feedstocks for Cold Spray Additive Manufacturing of Metal-Polymer Composites
Authors: Schwenger Matthew S. , Kaminskyj Madison S. , Haas Francis M. , Stanzione Joseph F. 
Published: May 2023

Abstract
High-performance polymers such as poly(ether ether ketone) (PEEK) are appealing for a wide variety of industrial and medical applications due to their excellent mechanical properties. However, these applications are often limited by relatively low thermal stability and conductivity compared to metals. Many methods developed to metallize polymers, including vapor deposition and thermal spray processes, can lead to poor quality control, low deposition rate, and high cost. Thus, cold spray is a promising potential alternative to rapidly and inexpensively produce polymer-metal composites. In this study, we investigated the deposition characteristics of metalpolymer composite feedstock, composed of PEEK powder with varying volume fractions of copper (Cu) flake added, onto a PEEK substrate. We prepared the Cu-PEEK composite powder in varying compositions by two methods: hand-mixing the powders and cryogenically milling the powders. Scanning electron microscopy (SEM) of the feed mixtures shows that cryogenically milling the polymer and metal powders together created uniformly distributed micron-scale domains of Cu on PEEK particle surfaces, and vice versa, as well as consolidating much of the porous Cu flake. In lowpressure cold spray, the relatively large volume fractions of PEEK in the composite mixtures allowed for lower operating temperatures than those commonly used in PEEK metallization (300-500 °C). While the deposition efficiencies of each mixture were relatively similar in single-layer experiments, deposits formed after multiple passes showed significant changes in deposition efficiency and composition in PEEK-rich feedstock mixtures. SEM of deposit surfaces and cross-sections revealed multiple co-dominant mechanisms of deposition, which affect both the porosity and final composition of the deposit. Though present in all samples analyzed, the effects of cryogenic milling were more prevalent at lower Cu concentrations.
Methods for 3D Volume Building in Cold Spray Additive Manufacturing
Authors: Wu Hongjian , List Alexander , Gärtner Frank , Klassen Thomas , Deng Sihao 
Published: May 2023

Abstract
Cold spraying (CS) has proved as an attractive and rapidly developing solid-state material deposition process that allows for fast formation of high quality, large 3D volume objects. Low risks of undesirable heat effects lead to increased interest in CS-based rapidly additive manufacturing (AM). However, by continuous powder spraying and high-pressure gas operation, cold spray additive manufacturing (CSAM) in terms of shape building is rather sensitive to operating parameters and imposes high requirements on the control of process conditions and locally needed kinematics. Every step of the manufacturing process therefore needs to be well conceived and planned, especially with regard to the toolpath planning and implementation. This is not only essential to meet basic performance requirements, but also needed to realize the desired accuracy. In order to tackle above needs, the present study presents a new toolpath planning method for 3D volume build-up to improve manufacturing accuracy and flexibility by cold spray additive manufacturing. Applied benchmarking tests prove acceptable shape accuracy and demonstrate that the current method can enhance the capabilities of CSAM for nearnet shape construction. This implies that careful planning and manufacturing strategies should enable to overcome the challenges associated with CSAM.
Analyzing Cold Spray of Polymer-Coated Metal Particles on Polymeric and Composite Substrates
Authors: Singh Nand Kishore , Mennie Nicholas Beau , Nault Isaac , Koohbor Behrad , Haas Francis M. , Jha Ratneshwar 
Published: May 2023

Abstract
Metallization of polymers and fiber-reinforced polymer composites is gaining attention due to the widespread application of these components in various industries, such as wind energy, aerospace, and automotive industries. Cold spray is a promising new technique to achieve the metallization of polymer and fiber-reinforced polymer composites. This work investigates the deposition mechanisms of polymer-coated metallic particles on polymer-based substrates by finite element analyses. Impact mechanics of PEEK-coated nickel particles impacting PEEK and carbon fiber-reinforced PEEK substrates are modeled. Results show the prominence of mechanical interlocking of metallic particles in the substrate, which occurs due to their entrapment inside the substrate, caused by the high energy impact-induced welding of scraped PEEK coating. The PEEK coating acts as a cushioning component, effectively mitigating the impact energy of the metallic component. The scraped PEEK coating also accumulates on the upper half of the particle, forming a cap welded to the substrate and sealing the metallic particle inside. It is observed that the depth of the carbon fiber mat in the substrate affects the mechanism and the success of deposition.
Cold Spraying of Inconel 625 Thick Deposits
Authors: Taherkhani Farrokh , List A. , Keller S. , Kashaev N. , Gärtner F. , Klassen T. 
Published: May 2023

Abstract
Cold spraying (CS) of high strength materials, e.g., Inconel 625 is still challenging due to the limited material deformability and thus high critical velocities. Further fine tuning and optimization of cold spray process parameters is required, to reach higher particle impact velocities as well as temperatures, while avoiding nozzle clogging. Only then, sufficiently high amounts of well-bonded particle-substrate and particle-particle interfaces can be achieved, assuring high cohesive strength and minimum amounts of porosities. In this study, Inconel 625 powder was cold sprayed on carbon steel substrates using N2 as propellant gas under different refined spray parameter sets and powder sizes for a systematic evaluation. Coating microstructure, porosity, electrical conductivity, hardness, cohesive strength and residual stress were characterized in as-sprayed condition. Increasing the process gas temperature or pressure leads to low coating porosity of less than 1 % and higher electrical conductivity. The as-sprayed coatings show microstructures with highly deformed particles and well bonded internal boundaries. X-ray diffraction reveals that powder and deposits are present as γ- solid-solution phase without any precipitations. By work hardening and peening effects, the deposits show high microhardness and compressive residual stresses. With close to bulk material properties, the optimized deposits should fulfill criteria for industrial applications.
Design of Powder Feedstocks for Net Shape Coatings
Authors: Lanz Oliver , Schubert Manuel , Goes Wellington , Ruggiero Giuseppe , Björklund Stefan , Joshi Shrikant 
Published: May 2023

Abstract
For the last few years, the HVAF process has been established as a commercially used process and has gained an increasing share in the market of thermal spraying. The main thermal spray materials being used for HVAF spraying have been those based on the tungsten carbide family. Economical aspects and European regulations on chemicals management REACH (Registration, Evaluation and Authorisation of Chemicals) have motivated the demand for thinner WC based coatings, which are still dense and wear resistant. This demand has progressively increased, and the trend shows a further growth in the need for thermal spray feedstock for HVAF sprayed net shape coatings. The challenge for powder producers lies in providing suitable spray powders, with high and consistent quality as well as in considerable volume, to be able to make reliable recommendations to the users of HVAF technology. A deeper understanding of powder requirements for net shape coatings, matching the needs with new powder solutions, and appreciation of the differences in behavior or performance depending on powder type are essential to address the above challenges and constitutes the theme of this paper.
Alloy Design of Feedstock Material for Additive Manufacturing—Exploring the Al-Co-Cr-Fe-Ni-Ti Compositionally Complex Alloys
Authors: Gerdt L. , Müller M. , Heidowitzsch M. , Kaspar J. , Lopez E. , Zimmermann M. , Leyens C. , Hilhorst A. , Jacques P.J. 
Published: May 2023

Abstract
The need for sustainable use of resources requires continuous improvement in the energy efficiency and development of new approaches to the design and processing of suitable materials. The concept of high entropy alloys (HEAs) has recently been extended to more general compositional complex alloys (CCAs) and multi-principal element alloys (MPEAs). One of the major challenges on the way to application of these alloys is the extensive design and selection efforts due to the great variety of possible compositions and its consequences for workability and resulting material properties. The favorable high-temperature strength of Ni-based and Co-based superalloys is ascribed to a defined γ/γ’ structure consisting of a disordered FCC A1 matrix and ordered L12 γ’ precipitates. In the current work we extended this design concept to CCAs, allowing disordered BCC A2 and ordered B2 phases in additions or in substitution of the original γ/γ’ structure. We used a high-throughput screening approach combining CALPHAD-based computational tools with in situ alloying by means of laser cladding. Wall-type specimens with gradient composition in the system Al-Co-Cr-Fe-Ni-Ti with varying Al, Ti and Cr content were analyzed. The combined modelling and experimental screening approach was demonstrated to be a powerful tool for designing new high performance AM-ready feedstock.
Effects of Thermal Exposure on Microstructure of Thermal Barriers Deposited by Hybrid Plasma Spraying
Authors: Musalek Radek , Tesar Tomas , Medricky Jan , Lukac Frantisek , Dudik Jonas 
Published: May 2023

Abstract
Hybrid plasma spraying combines plasma spraying of dry powders and liquids (suspensions and solutions). Combination of these two approaches allows deposition of microstructures consisting of both conventional coarse and ultrafine splats. Moreover, splats with dissimilar size may have also different chemistry. Such combination is potentially interesting for many fields of thermal spraying, including thermal barrier coatings (TBCs), as novel microstructures may be economically and relatively easily obtained. The technology has recently reached a level, where coatings with interesting hybrid microstructures may be reliably deposited, so that their potential for practical applications may be evaluated. In this study, first experimental TBCs with YSZ-based hybrid topcoat were deposited by hybrid water/argon stabilized plasma (WSP-H) technology. Al2O3 and YAG were selected as secondary phase deposited from suspension as both provide strong materials contrast in scanning electron microscope (SEM) so they can be used as “markers” in the coating microstructure. Samples were exposed to thermal cycling simulating in-service TBC conditions in order to test their thermal shock resistance. Changes of the coating microstructure were studied by SEM analysis and X-ray diffraction.
Influence of Size and Mixing Ratio of Micro-Forging Particle on Al Alloy Coating Structure via an In-Situ MF Cold Spray with Simultaneous Injection of Powder form Axial/Radial Directions of Nozzle
Authors: Sakaki Kazuhiko , Saito Chilhaya , Kawakami Ryo 
Published: May 2023

Abstract
In our laboratory, we have developed a method to simultaneously inject different powders from the central axis direction and radial direction of the cold spray nozzle and are producing a composite coating by this method. In the previous research of our laboratory, an Al-12Si alloy coating with excellent wear resistance was produced by micro-forging assisted cold spray using the simultaneous nozzle injection method of powder in the axial and radial directions. Here, Al- 12Si alloy, which has excellent wear resistance, was used for the coating-formed particles, and stainless steel was used for the micro-forging particles. However, because the micro-forging particles were hollow, they remained in the coating. In this paper, we evaluated the influence of increasing the mixing ratio of micro-forging particles instead of solid (no holes) micro-forging particles on the coating structure. At the same time, the behaviors of particles by computational fluid dynamics are also investigated.
A Study on the Powder Manufacturing Effect on Flowability and Deformability of Pure Cu Powders in Cold Spray Application
Authors: Eftekhari Niloofar , Saha Dulal , Jahed Hamid 
Published: May 2023

Abstract
The quality of feedstock powder is a critical factor in determining the properties of coatings deposited using cold spray (CS). However, most commercially available powders are not designed or optimized for CS applications, making it challenging to tailor powders to desired quality. In this research, we investigated and compared the cold-sprayability of four different Cu powders produced by electrolysis and gasatomization methods. We assessed the powders' microstructure, particle morphology and size distribution to understand the effect of manufacturing methods on Cu powder characteristics. We also studied the flowability of the powders using the shear cell method and evaluated their mechanical properties and deformability for CS using nano-indentation. Our results showed that gas-atomized powders with equiaxed grains exhibited promising flowability and deformability for CS applications, outperforming the other powders tested. Specifically, the spherical morphology of gas-atomized powders provided less surface area than the irregular-shaped electrolytic powder, reducing the interaction of surface forces and contributing to smooth powder flow. Additionally, the gasatomized powder with small dendrites in the microstructure exhibited the highest nano-hardness value (HIT= 1.6±0.1 GPa), while the porous electrolytic Cu powder had the lowest value (HIT= 0.7±0.2 GPa). In conclusion, we found that gas-atomized Cu powders with equiaxed grains may hold promise as the optimised feedstock for CS application, considering both effective metrics of flowability and deformability.
Suspension Sprayed YSZ Thermal Barrier Coatings on Inconel 718 Aerospike Manufactured by Laser Powder Bed Fusion
Authors: Toma Filofteia-Laura , Gruber Samira , Selbmann Alex , Leyens Christoph , Propst Martin , Dorau Tim , Bach Christian 
Published: May 2023

Abstract
Additive Manufacturing (AM) processes offer geometrical freedom to design complex shaped parts that cannot be manufactured with conventional processes. This leads to new applications including aerospace propulsion systems where the Ni-superalloy based material has to withstand high operating temperatures. In this contribution suspension plasma sprayed YSZ TBC coating was applied on the spike contour of an additively manufactured aerospike engine demonstrator. The engine was designed for a hydrogen peroxide / kerosene 6 kN thrust at 2.0 MPa chamber pressure and was manufactured from nickel-based superalloy Inconel 718 powder using the laser powder bed fusion process (LPBF). Due to the novelty of the application of suspension sprayed YSZ thermal protection coatings on additively manufactured Inconel 718 components, extensive tests were necessary to characterize the interaction between the coating and the component.