bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Velocity Suspension Flame Spraying and Suspension Plasma Spraying of Oxide Ceramics
Authors: Killinger A. , Müller P. , Gadow R. 
Published: January 2023

Abstract
Thermal spraying of oxide ceramic suspensions containing fine and ultrafine powder particles is a new approach for manufacturing ceramic coatings exhibiting a refined microstructure. Suspension sprayed coatings clearly differ from conventionally sprayed coatings regarding microstructure phase composition and resulting mechanical properties. Several industrial applications may take advantage in future; among these are thermal barrier structures, thermal shock protection, solid electrolytes, catalytically active surfaces and wear resistant coatings. Two methods, namely Suspension Plasma Spraying (SPS) and High Velocity Suspension Flame Spraying (HVSFS) are suitable to process suspensions but lead to rather different coating structures due to differences in the achievable particle velocities and temperature. Generally, HVSFS can lead to more dense coatings with low porosity values. With SPS on the other hand, coatings with a high volume fraction of porosity featuring a homogeneous pore structure are achievable. The presentation will compare SPS and HVSFS regarding the spray process, achieved properties of the oxide coatings and potential applications.
Robot Trajectory Planning for High Quality Thermal Spray Coating Processes on Complex Shaped Components
Authors: Floristán M. , Montesinos J. A. , García-Marín J. A. , Killinger A. , Gadow R. 
Published: January 2023

Abstract
Industrial robots are widely used in thermal spraying operations in order to assure process accuracy and reproducibility, as well as to increase worker´s safety. Robot path planning for the coating of free form geometries keeping constant the kinematic parameters can lead to complex robot paths and in some cases to unreachable robot configurations. An external rotational axis in coordinated movement with the robot can be used to manipulate complex shaped components during the spraying operation and to simplify the robot movement. Moreover, the robot kinematics, which define the spraying path, spray angle, spray distance and spray velocity, are key parameters to control the heat and mass transfer to the substrate during the coating deposition, and they influence therefore the development of residual stresses. The present work describes the off-line planning of robot trajectories for thermal spraying operations using an external rotational axis taking into consideration the heat transfer to the component.
Numerical Analysis of Solution Mixture and Torch Design in High-Velocity Suspension Flame Spraying
Authors: Dongmo E. , Wenzelburger M. , Gadow R. 
Published: January 2023

Abstract
High-velocity suspension flame spraying (HVSFS) is used for direct processing of submicron and nano-scaled particles to achieve dense surface layers in supersonic mode with a refined structure, from which superior properties are expected. The application of solutions as a carrier fluid for nano-particles in thermal spray systems is a new approach that requires some thermo-physical and chemical optimization. Three dimensional modeling and analysis of the combustion and gas dynamic phenomena of the three-phase HVSFS process is performed in this study for an industrial TopGun-G torch, based on a numerical model for a conventional HVOF process. Parameter analysis of the solution mixture (proportion between aqueous and organic solvent) in a suspension is performed as well as analysis of the variation of the combustion chamber depending on the torch design, leading to more homogeneous flow properties for an improved HVSFS torch.
Application of HVOF and HVSFS for High Performance Mass Transport Vehicle Chassis Components
Authors: Heyd S. , Manzat A. , Killinger A. , Gadow R. 
Published: January 2023

Abstract
Efficient transport is a key requirement for a powerful economy and will continue to gain importance leading to the necessity for high performance transport vehicles. A highly loaded major component of trains is the chassis. With increasing load, new materials and concepts have to be developed in order to increase the performance of these components. One approach to improving chassis components like bearings for chassis components is the deployment of thermally sprayed coatings by means of HVOF and HVSFS, which can significantly improve their wear resistance, prolong their life time and simultaneously reduce frictional losses. Using the example of spherical bearings, several HVOF sprayed metallic, cermetic and ceramic coatings have been tested for their ability to improve the properties of the components. In addition to metallographic investigations, extensive mechanical tests on test rigs have been carried out to determine the performance of the coatings under realistic conditions.
Military Adoption of Kinetic Metallization
Authors: Tapphorn R. , Gabel H. , Hashimoto K. , Wahl Weston , Crowe T. 
Published: January 2023

Abstract
The low temperature Kinetic Metallization (KM) deposition process is compliant with the recently revised MIL-STD-3021 standard for cold spray materials deposition. KM deposition process and equipment was supported through the US Military via multiple Small Business Innovative Research (SBIR) grants leading to delivery of KM deposition equipment to multiple branches. Coating application areas discussed in this paper include wear resistant tungsten-carbide and chromium-carbide hard-phase coatings. These are used for aircraft engines and landing gear surfaces with firm low temperature deposition requirements. Other areas include aluminum and magnesium dimensional restorations, in particular for Aircraft Mounted Accessory Drive (AMAD) gearboxes for F-18 platforms, and land vehicle housings and casings for the US Marines Corps.
Improved Coatings for Extended Design Life of 22%Cr Duplex Stainless Steel in Marine Environments
Authors: Paul S. , Lee C. M. , Harvey M. D. F. 
Published: January 2023

Abstract
In this paper evaluation of sealed and unsealed thermally sprayed aluminum (TSA) for the protection of 22%Cr duplex stainless steel (DSS) from corrosion in aerated, elevated temperature synthetic seawater is presented. The assessments involved general and pitting corrosion tests, external chloride stress corrosion cracking (SCC), and Hydrogen induced stress cracking (HISC). These tests indicate that DSS samples which would otherwise fail on its own in a few days do not show pitting or fail under chloride SCC and HISC conditions when coated with TSA (with or without a sealant). TSA-coated specimens failed only at very high stresses (&gt;120% proof stress). In general, TSA offered protection to the underlying or exposed steel by cathodically polarizing it and forming a calcareous deposit in synthetic seawater. The morphology of the calcareous deposit was found to be temperature dependent and in general is of duplex nature. The free corrosion rate of TSA in synthetic seawater was measured to be ~5-8 µm/year at ~18°C and ~6-7 µm/year at 80°C.
Utilizing Computational Metallurgy to Design Amorphous and Nanocrystalline Coatings for Wear and Corrosion Resistance
Authors: Cheney J. , Kusinski G. 
Published: January 2023

Abstract
Computational metallurgy is a technique being used and developed in the field of bulk alloys to design and develop novel amorphous and nanocrystalline materials. This technology can be transitioned to develop chemistries for both wear and corrosion resistant thermal spray coatings. Using computational metallurgy and small scale laboratory experiments, nanostructured and amorphous chemistries can be designed to specifically accommodate one of the many environmental conditions challenging the oil and gas industry. This study reviews the design procedures behind developing three unique chemistries intended to function in different environments: 1) an Fe-based chemistry designed for metal to metal sliding wear resistance, 2) an Fe-based chemistry containing elevated refractory content intended specifically for spray and fuse applications to resist sulfurous corrosion, and 3) a Ni-based chemistry similar to Alloy C276 for high temperature corrosion resistance. All three alloys were designed using computational techniques and eventually manufactured into cored wires for use within the twin wire arc spray (TWAS) process. The fine grained structure provides unique benefits to each application including 1) high hardness, 2) ability to rapidly form protective scale, 3) low melting temperature and creep resistance.
Multi-Response Optimization of Process Parameters for Low-Pressure Cold Spray Coating Process Using Taguchi and Utility Concept
Authors: Goyal Tarun , Walia R.S. , Sidhu T.S. , Sidhu H.P.S. 
Published: January 2023

Abstract
In this research work, an approach based on a Utility theory and Taguchi quality loss function (TQLF) has been applied to low-pressure cold spray (LPCS) process to deposit copper coatings, for simultaneous optimization of two potential response parameters i.e. coating thickness (CT) and surface roughness (SR). Utility values based upon these response parameters have been analyzed for optimization by using Taguchi approach. The selected input parameters of powder feeding arrangement, air stagnation pressure, air stagnation temperature and stand-off distance except substrate material, significantly improves the Utility function (raw data and S/N ratio) comprising of quality characteristics (coating thickness and surface roughness). The percentage contribution of the parameters to achieve a higher value of utility function is: stand-off distance (55.86%), air stagnation temperature (16.58%), air stagnation pressure (14.20%), powder feeding arrangement (5.12%) and substrate material (0.16%) respectively.
Knudsen Effect on the Computed Effective Thermal Conductivity of Thermal Spray Coatings
Authors: Qiao J.H. , Bolot R. , Liao H.L. , Coddet C. 
Published: January 2023

Abstract
To implement image-based numerical modeling of the thermal conductivity of coatings, a YSZ coating was considered as a network of two phases, namely the coating material and pores. The variation of the thermal conductivity of the gas trapped within the pores caused by their small size was considered by complying with the Knudsen law. In the present work, the quantification of the Knudsen effect on the effective thermal conductivity of coatings was achieved with the help of image analysis. The thicknesses of the pores were determined by combining the use of the Scion image software with a new in-house algorithm coded in C language. The Knudsen effect was quantified by applying a finite-difference model for both 2D images and a 3D image. In both cases, a decrease of the computed thermal conductivity was found while considering the Knudsen effect. Furthermore, the Knudsen effect was also taken into account in a finite-element model applied on the same images. Despite differences were noticed on the computed thermal conductivities obtained with the two methods, a quite similar decrease was calculated by comparing with data computed with the FDM method.
Fabrication of Porous Stainless Steel through Semi-Molten Spray Particles Deposition by Flame Spraying
Authors: Yao J.-T. , Li C.-J. , Yang G.-J. , Li C.-X. 
Published: January 2023

Abstract
Porous materials possess many unique properties. Many processes have been employed to fabricate porous materials. Recently, it was found that a porous deposit can be created through controlling the deposition of semi-molten spray powder particles. In this study, porous 316L stainless steel deposits were prepared by flame spraying under different spray conditions to aim at controlling deposit porosity. During deposition the temperature of the substrate and/or deposit surface was kept at 600°C to ensure bonding formation between the spray particle and underlying particle. To understand the deposition process mechanism, the velocity of spray particles was quantitatively measured and the morphology of deposited isolated particles was characterized by scanning electron microscopy to estimate the melting degree of spray particles before impact. The microstructure of porous 316L stainless steel deposits was characterized by scanning electron microscopy and deposit porosity was estimated from its cross section by image analysis. It was found that pores were uniformly distributed in the deposit. The results showed that porosity of the 316L deposits changed from 20% to 50% with the change of spray particle melting degrees, resulting from the change of spray parameters. The examination showed that 3D through-deposit pore-net structure was created by viscoplastic flowing of the molten fraction of semi-molten particles which forms the bonding between necks of particles. The present results clearly demonstrated that a porous ferrous alloy based material can be formed by spray deposition through controlling the melting degree of spray particles.
Effect of Powder Structure on the Adhesion and Electrical Properties of TiN Coatings Deposited by Vacuum Cold Spray
Authors: Wang Y.-Y. , Zhang Y.-J. , Liu Y. , Li C.-J. , Yang G.-J 
Published: January 2023

Abstract
Sub-micro-structured titanium nitrides (TiN) coatings on Al2O3 substrates were fabricated by vacuum cold spray (VCS) process using ceramic powders, which were ball-milled at room temperature. The microstructure features and crystal structures of the VCS TiN coatings were analyzed by scanning electron microscopy and X-ray diffraction. The adhesion between the coating and the substrate was evaluated with a scratch tester. The sheet resistance of the VCS TiN coatings was measured by using a four-point probe method. The effects of nozzle traverse speed on the microstructure, adhesion to substrate and electrical properties of the coatings were investigated. It was found that the adhesion improves greatly with the nozzle traverse speed increasing from 5 to 15mm/s, and the electrical resistivity levels of the coatings is decreased significantly. The resistivity of sub-micron-structured TiN coatings is substantially lower than those of nano-structured ones fabricated by the same VCS process. And a minimum resistivity of 1.16×10-4 Ω·m is achieved.
Bilayer Plasma-Sprayed Alumina for Optical Applications
Authors: Marthe J. , Meillot E. , Enguehard F. , Jeandel G. 
Published: January 2023

Abstract
Materials with fine-scale structures are recognized to exhibit technologically efficient mechanical or thermal properties. Thermal sprayed nanostructured media could also be interesting in the optical field thanks to the diffusion interaction between short wavelength radiations and submicron-sized pores. One difficulty of the Suspension Plasma Spray (SPS) technique is to provide a sufficiently thick coating and to maintain efficient mechanical properties when the coating is removed from the substrate. The aim of this study was to spray a reflective and diffusive self-supporting alumina bilayer. The first coating was obtained by Atmospheric Plasma Spraying of micron-sized powders in order to obtain a thick layer and the second coating was sprayed by SPS onto the first one with strong adhesion. An oxide ceramic material with high scattering reflectance in a large band of wavelengths was thus obtained.
Study on the Mechanism of Adhesion Improvement Using Dry-Ice Blasting for Plasma-Sprayed Al2O3 Coatings
Authors: Dong S.-J. , Song B. , Liao H.-L. , Coddet C. , Hansz B. 
Published: January 2023

Abstract
A previous study indicated that improved adhesions of plasma-sprayed Al2O3 coatings have been achieved by using dry-ice blasting. Therefore, it is important to understand the mechanisms involved. In this study, the surface roughness of different substrates treated by dry-ice blasting was firstly examined. And then the surface wettability was characterized in order to clarify the effect of dry-ice blasting on the substrate surface properties. The effect of dry-ice blasting on Al2O3 splat morphology with different treatment times was investigated. The residual stress of plasma-sprayed Al2O3 coatings using dry-ice blasting was measured and compared with that of coatings deposited with conventional air cooling. Based on these numerous assessment tests, it could be concluded that the cleaning effect of dry-ice blasting on different organic substances adsorbed on the substrates was the most important influence on the adhesion improvement of Al2O3 coatings.
A Simplified Model for Prediction of HVOF NiCr Coating Properties through Experimental Design and Diagnostic Measurements
Authors: Zois D. , Wentz T. , Sampath S. 
Published: January 2023

Abstract
An empirical model was built for the prediction of HVOF sprayed NiCr in-flight particle properties based on the spraying parameters. The employment of factorial design in process parameter development, allowed determination of the contribution of the key process variables, such as flame energy (combustion pressure and O2/F ratio), spray distance and feed rate, on the resultant particle velocities and surface temperatures. The significance of each parameter was used to compose a simple model which enabled the description of the particles’ in-flight properties. Particles with velocities ranging as much as 300 m/s and temperatures ranging up to 350 °C were used to produce a range of coatings on an in situ curvature sensor enabling the determination of evolving and residual stress. These diverse particle states combined with the effect of flame impingement on the substrate, resulted in coatings of similar thickness, but significantly different stress states. Real time evolving stresses during deposition were interrelated to particle in-flight properties and, consequently, to spraying parameters.
Multiple-Approach Evaluation of WSP Coatings Adhesion/Cohesion Strength
Authors: Musalek R. , Vilemova M. , Matejicek J. , Pejchal V. 
Published: January 2023

Abstract
Adhesion/cohesion testing represents one of the most common methods for benchmarking and optimization of thermal spray coatings. However, due to the inhomogeneous coating microstructure, such testing may be quite troublesome. In this study, adhesion/cohesion strength of representative metallic and ceramic coatings deposited by Water Stabilized Plasma (WSP) spraying was evaluated by different methods, namely Tensile Adhesion Test (TAT), newly utilized pin test and Tubular Coating Tensile (TCT) test. Combination of various methods enabled the evaluation of the splat bonding quality in different loading modes. Limitations and benefits of each method for testing of WSP coatings are demonstrated. Dominating failure micromechanisms were determined by supplementary fractographic analysis.
Adhesion Properties of Sprayed Coatings on Substrate Blasted by Multiangle Blasting
Authors: Maruyama T. , Kishita T. 
Published: January 2023

Abstract
Adhesion properties on the substrate blasted by multi-angle blasting with white alumina grit were examined. The low carbon steel substrates were blasted at two blasting angles (high and low angles) in a multi-angle blasting process. The sprayed coating of zinc alloy was evaluated by an adhesion test. The surface roughness levels after the multi-angle blasting were lower than those in the case of normal blasting. The multi-angle blasting was an effective blasting process to obtain improved adhesive properties. The low blasting angle may have contributed for removing contamination from the substrate surface. The high blasting angle may have contributed for an effective surface roughness to enhance the adhesive properties.
Cladding by Plasma Transferred Arc Process: Effect of the Process on Plasma Parameters Behavior and Molten Bath
Authors: Lucas H. , Denoirjean A. , Vardelle M. , Furlani A.M. 
Published: January 2023

Abstract
Coatings, a few-millimeter thick, are widely used to protect new mechanical parts against abrasion and erosion or rebuild worn parts. The plasma transferred arc process is a commonly used process to deposit such coatings. It makes it possible to bring about a metal bath inside which melted powders are introduced to form an alloyed coating between the feedstock material and substrate material with metallurgical adhesion. The main parameters of the process are the arc current intensity, plasma and shrouding gas flow rates, distance between the cathode tip and piece, velocity of plasma torch displacement; they all have a notable effect on the produced coating. This study investigates the plasma behavior and properties of the clad by using a design of experiments. The properties of the coating are the dilution level, porosity, and efficiency of material deposition, heat flux transferred to a water-cooled calorimeter, and the hardness in the clad and the substrate to estimate the thermally affected area.
Erosion and Abrasion Resistance of Fe2B-Based Arc-Sprayed Coatings and Weld Overlays Containing Chromium and Carbon
Authors: Dallaire S. 
Published: January 2023

Abstract
Earlier works have demonstrated that Fe2B-based arc-sprayed coatings and weld overlays present outstanding dry erosion resistance when compared to other carbide-based coatings and overlays. The present work was undertaken to examine their wear resistance, particularly their slurry erosion resistance. Cored wires containing chromium (2-20 wt%) and carbon (0.2-1.2 wt%) additives were deposited by arc spraying and gas metal arc welding (GMAW). The abrasion, particle erosion and slurry erosion resistances of these (Fe-B-Cr-C) coatings and overlays were evaluated in laboratory. The results demonstrate that both differences in cored wire composition and variations in the deposition process must be considered in order to obtain the best wear properties.
The Influence of Process Equipment on the Properties of Suspension Plasma Sprayed Yttria-Stabilized Zirconia Coatings
Authors: Marr M. , Waldbillig D. , Kesler O. 
Published: January 2023

Abstract
Suspension plasma sprayed YSZ coatings were deposited at lab-scale and production-scale facilities to investigate the effect of process equipment on coating properties. The target application for these coatings is SOFC electrolytes, so dense microstructures with low permeabilities were desired. Both facilities had the same torch but different suspension feeding systems, torch robots and substrate holders. These differences meant that the lab facility had higher torch-substrate relative speeds compared to the production facility. When using porous stainless steel substrates with relatively smooth surfaces, permeabilities and microstructures were comparable for coatings from both facilities, and no segmentation cracks were observed. Coating permeability could be further reduced by increasing substrate temperatures during deposition or reducing suspension feed rates. On rougher substrates representative of SOFC cathodes, production facility coatings had higher permeabilities and more segmentation cracks compared to lab coatings. The increased cracking may be due to larger heat impulses with each torch pass at the production facility caused by its lower torch-substrate relative speed. This work highlights some of the challenges associated with scaling up the spray process from the lab to production.