bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Feedstock Powder for Fabrication of Aluminum Nitride in Reactive Atmospheric Plasma Spray Process
Authors: Shahien M. , Yamada M. , Yasui T. , Fukumoto M. 
Published: September 2022

Abstract
It was possible to fabricate cubic-AlN (c-AlN) based coating through the reaction between Al powder and the N2/H2 plasma in APS system. The fabricated coating was about 100 μm with hardness about 540 Hv, which is much higher than the hardness of Al. The formation of the cubic phase in APS is directly related to the rapid solidification phenomena of plasma spraying process. The sprayed powder particles show rapid cooling rates upon impact with the substrate, which prevent its complete crystal growth. The nitride content increased with the spray distance due to increase the flight time of Al particles in the N2 plasma. Using smaller particle size improved the nitriding reaction at short spray distance due to increasing the particle temperature. However increasing the particle temperature leads to excessive vaporization of Al particles and completing nitriding reaction during flight, therefore suppressing the coatings thickness. The nitriding reaction of the larger particle size Al powders can be enhanced through NH4Cl powders addition. That NH4Cl addition changed the reaction pass way from liquid-gas to vapor-phase intermediate mechanism.
Vapor Phase Deposition Using a Plasma Spray Process
Authors: Niessen K. von , Gindrat M. 
Published: September 2022

Abstract
Plasma spray – physical vapor deposition (PS-PVD) is a low pressure plasma spray technology to deposit coatings out of the vapor phase. PS-PVD is part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well established low pressure plasma spraying (LPPS) technology. Included in this new process family are plasma spray - chemical vapor deposition (PS-CVD) and plasma spray - thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying (VPS) and low pressure plasma spraying (LPPS), these new processes use a high energy plasma gun operated at a work pressure below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional physical vapor deposition (PVD) technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. In contrast to EB-PVD, PS-PVD incorporates the vaporized coating material into a supersonic plasma plume. Due to the forced gas stream of the plasma jet, complex shaped parts like multi-airfoil turbine vanes can be coated homogeneously with columnar thermal barrier coatings using PS-PVD. This paper reports on the progress made by Sulzer Metco to develop a thermal spray process to produce coatings out of the vapor phase.
Selective Impact of Industrial Gases on the Thermal Spray Process
Authors: Krömmer W. , Heinrich P. 
Published: September 2022

Abstract
The trend in thermal spraying is more and more towards a globally uniform level of high-grade spray coatings. It is therefore extremely important that auxiliaries such as spray materials or industrial gases undergo precise examination in order to exactly define their influence. A further point is of particular significance in today’s business world. With ever-increasing raw material prices, it is absolutely essential that spray processes are optimized to the maximum. This is not only made possible by selecting the right system, but also by choosing the right gas and gas mixture. The optimization of costs, extended lifetime of systems and tailoring of coating properties to suit specific applications are just some of these influencing variables. Gas producers test countless facilities and thermal spray systems in their own laboratories and are therefore always in a position to provide the right solution for existing and new applications.
Potential of Cold Gas Spraying in Power Electronic Applications
Authors: Donner K.-R. , Gaertner F. , Klassen T. 
Published: September 2022

Abstract
A successful combination of isolating substrates with conducting metal coatings produced by cold spraying could open new industrial application areas like the fabrication of power electronic components. For minimizing the number of industrial process steps, isolating ceramic layers should ideally be processed by thermal spray techniques. Thus, the present study investigates the impact behaviour and coating formation of ductile metallic feedstock powders onto brittle ceramic coatings. With respect to high electrical conductivity of the metallic lines and good electrical isolation of the ceramic interlayer, copper was cold gas sprayed on previously thermally sprayed Al2O3 coatings. Successful cold coating formation requests different strategies for the activation of the ceramic layer to increase adhesion and to avoid brittle failure. Both can be achieved by applying a bondcoat on the ceramic layer or by using heated substrates during the cold spray process.
Thermophysical Studies on Thermally Sprayed Tungsten Carbide-Cobalt Coatings
Authors: Thiele S. , Sempf K. , Jaenicke-Roessler K. , Berger L.-M. , Spatzier J. 
Published: September 2022

Abstract
The development of new hardmetal coating applications such as fatigue-loaded parts, structural components and tools for metal forming is connected with improvement of their performance and reliability. For modelling purposes the knowledge of thermophysical, mechanical and other material data is required. However, this information is still missing today. In the present work the thermophysical data of a WC-17Co coating sprayed with a liquid-fuelled HVOF-process from a commercial agglomerated and sintered feedstock powder from room temperature up to 700 °C was determined as an example. The dependence of the heat conductivity on temperature was obtained through measurement of the coefficient of thermal expansion, the specific heat capacity and the thermal diffusivity. Heat conductivities ranging from 29.2 W/(mK) at 50°C to 35.4 W/(mK) at 700 °C were determined. All measurements were performed twice (as-sprayed and after the first thermal cycle) in order to take into account the structural and compositional changes. Extensive XRD and FESEM studies were performed in order to characterize the phase compositions and microstructures in the as-sprayed and heat-treated states. Bulk samples obtained by spark plasma sintering from the feedstock powder were studied for comparison.
Microstructure and NO2 Sensing Performance of APS ZnO Coatings
Authors: Zhang C. , Debliquy M. , Liao H. 
Published: September 2022

Abstract
This work studied the possibility of using a sensor based on plasma-sprayed zinc oxide (ZnO) sensitive layer for NO2 detection. The atmospheric plasma spray process was employed to deposit ZnO gas sensing layer and the obtained coating structure was characterized by scanning electron microscopy and X-ray diffraction analysis. The influences of gas concentration, working temperature, water vapor in testing air on NO2 sensing performance of the ZnO sensors were studied. ZnO sensors showed a good sensitivity and selectivity to NO2 at an optimal working temperature.
The Influence of Particle Temperature, Particle Velocity and Coating Surface Temperature on the Sliding Wear Performance of TiO2-Cr2O3 Coatings
Authors: Trache R. , Berger L.-M. , Saaro S. , Lima R.S. , Marple B.R. 
Published: September 2022

Abstract
In this work the sliding wear resistance of HVOF and APS-sprayed coatings from two experimental TiO2-10-20 wt.%Cr2O3 fused and crushed feedstock powders was investigated. During the spraying process the particle temperatures and velocities were mapped in the cross section of the spray jet at different spray distances. In addition, the coating surface temperature was monitored. Coating microstructures and phase composition were studied by SEM and XRD, respectively. The elastic modulus (E) and hardness (H) values were measured via in-depth sensing indentation. The unidirectional ball-on-disk sliding wear test was performed at room temperature against a tungsten carbide ball (sliding speed 0.05 m/s, normal force 90 N). The increase of the particle temperature and velocity leads to an increase of hardness and Young’s modulus of the coatings, thereby increasing their sliding wear resistance. The sliding wear resistance can be correlated with the H3/E2 ratio better than with the hardness alone. The sliding wear resistance was also sensitive to the coating surface temperature reached during deposition.
Cold Spraying for Titanium Dioxide Coatings with High Photocatalytic Bactericidal Activity
Authors: Kliemann J.-O. , Gutzmann H. , Gärtner F. , Klassen T. , Gabriel H. 
Published: September 2022

Abstract
Titanium dioxide in anatase phase structure has high antibacterial activity. For this study, titanium dioxide coatings on stainless steel were produced by cold spraying. The bactericidal effect of the coatings was tested with Pseudomonas aeruginosa bacteria at a high concentration of more than 107 CFU (colony-forming units) per milliliter. The bacteria were applied on the surface and exposed to UV light with a peak intensity of 360 nm. A kill rate of 99,99% was already achieved after 5 minutes, while the raw stainless steel reference did not show any significant reduction even after 60 min. The results show that cold-sprayed titanium dioxide coatings can serve as self-disinfecting surfaces.
Columnar Structured Thermal Barrier Coatings (TBCs) by Thin Film Low Pressure Plasma Spraying (LPPS-TFTM)
Authors: Hospach A. , Mauer G. , Vaßen R. , Stöver D. 
Published: September 2022

Abstract
The very low pressure plasma Spray (VLPPS) process has been developed with the aim of depositing uniform and thin coatings with large area coverage by plasma spraying. At typical pressures of 100-200 Pa, the characteristics of the plasma jet change compared to conventional low pressure plasma spraying processes (LPPS) operating at 5 – 20 kPa. The combination of plasma spraying at low pressures with enhanced electrical input power has led to the development of the LPPS-TF process (TF = thin film). At appropriate parameters it is possible to evaporate the powder feedstock material providing advanced microstructures of the deposits. This technique offers new possibilities for the manufacturing of thermal barrier coatings (TBCs). Besides the material composition, the microstructure is an important key to reduce thermal conductivity and to increase strain tolerance. In this regard, columnar microstructures deposited from the vapor phase show considerable advantages. Therefore, physical vapor deposition by electron beam evaporation (EB-PVD) is applied to achieve such columnar structured TBCs. However, the deposition rate is low and the line of sight nature of the process involves specific restrictions. In this paper, the deposition of thermal barrier coatings by the LPPS-TF process is shown. It is investigated how the evaporation of the feedstock powder could be improved and to what extend the deposition rates could be increased.
Effect of Heat Treatment on Porosity and Corrosion Performance of Cold Sprayed Titanium Deposits
Authors: Hussain T. , McCartney D.G. , Shipway P.H. , Marrocco T. 
Published: September 2022

Abstract
Cold gas dynamic spraying (CGDS) can be used to deposit oxygen sensitive materials, such as titanium, without significant chemical degradation of the powder and with minimal heating of the substrate. The process is thus believed to have potential for the deposition of corrosion resistant barrier coatings. However, to be effective a barrier coating must not allow ingress of a corrosive liquid and hence must have minimal interconnected porosity. Thus the aim of the present study was to investigate the effects of processing, including a post-spray annealing treatment, on the deposit meso- and microstructures and corrosion behavior. Commercially pure titanium powder was deposited using pre-heated nitrogen as main and powder carrier gas using a CGT Kinetiks 4000 system to produce coatings on stainless steel. Selected coatings were debonded from the substrate, and the resultant free standing deposits heat treated at 1050° C in vacuum for 60 minutes. Changes in microhardness were measured and correlated with microstructural changes. Optical microscopy, scanning electron microscopy, X-ray diffraction (XRD), helium pycnometry and mercury porosimetry were all employed to examine the microstructural characteristics of coatings and free standing deposits, before and after heat treatment. Their corrosion performance was also investigated using potentiodynamic polarization tests in 3.5 wt% NaCl. The influences of heat treatment and corrosion behavior will be analyzed and discussed in terms of pores structure evolution and microstructural changes.
A Preliminary Study of the Oxidation Behavior of TBC with Cold Spray CoNiCrAlY Bond Coat
Authors: Chen W.R. , Irissou E. , Legoux J.-G. , Wu X. , Marple B.R. 
Published: September 2022

Abstract
Cold gas dynamic spray (CGDS) utilizes a supersonic gas jet to accelerate fine solid powders above a critical velocity at which particles impact, deform plastically, and bond to the substrate material in the ambient environment. This process is potentially beneficial for thermal barrier coating (TBC) bond coat deposition because it would avoid oxidation of the feedstock powder that normally occurs when higher temperature thermal spray processes are employed. Therefore, there would be no prior aluminum depletion in as-deposited bond coats produced by the CGDS technique. This paper presents the oxidation behaviour of a TBC with CGDS-produced CoNiCrAlY bond coat, in comparison with TBCs with APS- and HVOF-CoNiCrAlY bond coats. Oxidation behaviors of these TBCs were evaluated in terms of microstructural evolution, kinetics of thermally-grown-oxides (TGO), as well as cracking behaviour during thermal exposure at 1050 °C.
Characterization of Thermo-Mechanical Properties for Thermal Sprayed NiCoCrAlY Coatings
Authors: Fasth A. , Nylén P. , Markocsan N. , Mušálek R. 
Published: September 2022

Abstract
The thermo-mechanical properties of a thermal barrier bond coat (BC) play an important role in governing the life-time of a coating system. The presented work aims to determine these properties for NiCoCrAlY coatings sprayed on Hastelloy X substrates sprayed under different process conditions. Temperature dependent Young’s modulus values are determined for both Atmospheric Plasma Sprayed (APS) and HVOF sprayed coatings using the four-point bending test. Particular attention is paid to microstructure-property relationships during heating. Young´s modulus was determined up to 950°C and evaluated for coatings loaded in both tension and compression. Results are discussed in the context of the effect of feedstock material, process conditions and microstructure characteristics. The methods and results presented are attractive, particularly for the thermal spray industry, since these properties are a prerequisite when the BC is to be considered in component design.
Deposition of NiO/YSZ Composite and YSZ by Suspension Plasma Spray on Porous Metal
Authors: Wang Y. , Legoux J.-G. , Neagu R. , Hui R. , Maric R. , Marple B.R. 
Published: September 2022

Abstract
The use of a liquid feedstock carrier in suspension plasma spray (SPS) permits injection of fine powders, providing the possibility of producing sprayed coatings that are both thin and dense and have fine microstructures. These characteristics make SPS an attractive process for depositing highly efficient electrodes and electrolytes for solid oxide fuel cell (SOFC) applications. In the present study, NiO-yttria stabilized zirconia (YSZ) anode and YSZ electrolyte half cells were successfully deposited on porous Hastelloy X substrates by SPS. The NiO-YSZ anode deposition process was optimized by design of experiment. The YSZ electrolyte spray process was examined by changing one parameter at a time. The results from the design-of-experiment trials indicate that the porosity of the as-deposited coatings increased with an increase of suspension feed rate while it decreased with an increase of total plasma gas flow rate and standoff distance. The deposition efficiency increased with an increase of total plasma gas flow rate, suspension feed rate and standoff distance. The microstructure examination by SEM shows that the NiO and YSZ phases were homogeneously distributed and that the YSZ phase had a lamellar structure. It was observed that the density of the YSZ electrolyte layer increased as input power of the plasma torch increased.
Development of a Low-Temperature, Oxy-Fuel (LTOF) Thermal Spray Gun
Authors: Dhiman R. , Farhadi F. , Pershin L. , Chandra S. , Mostaghimi J. 
Published: September 2022

Abstract
This paper presents the development of a new thermal spray gun for the so-called warm spraying process in which powder particles are not melted but heated to temperatures much higher than those typically found in a cold spray process. The increased heating leads to a reduction in the particle impact velocity required to deposit the coating and hence reduces operating cost. The new gun utilizes methane-oxygen combustion for particle heating and features a swirl-type combustion chamber to create a turbulent mixture of the fuel and oxidizer for efficient combustion. Powder can be fed axially or radially into the gun. To control particle temperature independently, combustion gases are diluted by adding nitrogen gas through axial or radial ports provided in the gun. A converging-diverging nozzle with a downstream cylindrical barrel accelerates the burnt gases to supersonic velocities. The design of the nozzle and barrel was optimized using numerical simulations. Mass flow rates of methane, oxygen, and nitrogen were calculated using energy balance, stoichiometric combustion, and nozzle flow rate equations. The gun is designed to operate up to 200 kW and is water-cooled. Experiments were conducted to test the performance of the new gun in which tungsten carbide coatings were deposited on aluminum substrates. Coatings were analyzed using standard methods and showed promising results.
Comparison of Cold Spray and Detonation Coatings Properties
Authors: Smurov I. , Pervushin D. , Ulianitsky V. , Zlobin S. , Sova A. 
Published: September 2022

Abstract
Cold and detonation spraying methods are based on the interaction of high-velocity particles with substrate. High quality coatings from various powder materials can be deposited. In both processes, the substrate experiences insignificant thermal effect. Thermally sensitive powder can be sprayed with no oxidation and decomposition. The initial powder microstructure and even nanostructure can be preserved under properly selected spraying conditions. This study is based on a comparative analysis of the mechanical, electrical, and heat transfer properties of a series of coatings deposited by cold and detonation spraying technologies. The coatings are produced from copper and aluminum powders using a commercial Cold Spray equipment CGT-4000 and an original computer-controlled detonation spraying (CCDS) installation developed by the authors. The coating microhardness, density, electrical and heat conductivity, adhesion, cohesion, etc. are measured and compared. Particular advantages and drawbacks of both spraying methods are discussed.
Correlations Between the Oscillation Modes of Arc Voltage and Pressure in Cathode Cavity of Dc Plasma Torches
Authors: Rat V. , Coudert J.-F. 
Published: September 2022

Abstract
The development of coating elaboration processes involving electric arcs depends on process stability and the capacity to ensure a constant reproducibility of coatings properties. This is particularly important when considering the plasma treatment of submicron or nanosized particles in Suspension Plasma Spraying (SPS). Submicron particles closely follow plasma instabilities and have non-homogeneous plasma treatment. Recently, it has been shown that arc voltage fluctuations in dc plasma torches, showing dominant fluctuation frequencies between 4 – 6 kHz, are linked to pressure oscillations in cathode cavity in the rear part of the plasma torch. These resonant oscillations are linked to plasma torch geometry. In this paper, first, we will present a method to isolate the different oscillations modes in measured arc voltage and pressure signals by the use of signal processing methods. Second, correlations between the different modes of oscillations are analyzed following the plasma torch operating parameters.
Investigation of Impact Behavior of Cold-Sprayed Large Annealed Copper Particles and Characterizations of Coatings
Authors: Li W.-Y. , Guo X.P. , Liao H. L. , Coddet C. 
Published: September 2022

Abstract
In this research, large gas-atomized copper powder was selected as the feedstock. Some powder was annealed in a vacuum circumstance to avoid to the greatest extent the effect of grain boundaries on the high velocity impact behavior of particles during cold spraying. Some powder was oxidized in a resistance furnace to clarify the effect of surface oxide films. Both the annealed and the oxidized Cu powders were deposited by cold spraying with respect to the single impacts and coating deposition under the same gas condition. In addition, the rebounded copper particles were collected for morphology analysis compared to the adhered particles. The results show that the average size of the rebounded particles is apparently increased compared to the starting powder because of the rebound of the larger particles and the intensive plastic deformation of particles. For the deposited particles, obvious plastic deformation causes the higher hardness of the coatings. The last but not the least finding in this study is the rebounded particles also experienced large deformation and possible shear instability at the impact interfaces.
Characterization and Performance Evaluation of a Helium Recovery System Designed for Cold Spraying
Authors: Legoux J.-G. , Irissou E. , Desaulniers S. , Bobyn J. , Harvey B. , Wong W. , Gagnon E. , Yue S. 
Published: September 2022

Abstract
This paper describes and evaluates the performance of a Helium Recovery System (HRS) designed for cold spraying. A flexible, automated, full scale HRS system has been designed and installed in the McGill Aerospace Materials & Alloy Development Center Cold Spray Facility, located at and in collaboration with the National Research Council of Canada. The fully automated HRS has been designed to recover helium from the cold spray chamber with sufficient purity (&gt;99%) and flow capacity (5 to 220 Nm3/h), allowing for a cost-effective operation by insuring a recovery rate of above 85%. In addition, a comparison of titanium coating properties obtained by using both He and N2 as propellant gas is presented.