bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Annealing Treatment on the Photocatalytic Performance of the Nanostructured TiO2 Coating Deposited by Vacuum Cold Spray
Authors: Yang G.-J. , Li C.-J. , Fan S.-Q. , Zhang L.-Z. , Li C.-X. , Wang Y.-Y. 
Published: September 2022

Abstract
Composite powder in sub-micrometer size was prepared using a primary nano-TiO2 powder and polyethylene glycol (PEG). The nano-TiO2 coating was deposited through vacuum cold spray using both the composite powder and primary nano- TiO2 powder. The influence of annealing treatment on coating adhesion and photocatalytic activity was investigated. The coating adhesion was estimated through erosion test by water jet. The photocatalytic performance of the TiO2 coatings was evaluated through photodegradation of phenol in water. The results showed that annealing of the coating at a temperature from 450 to 500 °C yielded both higher activity and better adhesion. The adhesion of the coating deposited using the composite powder was better than that using primary nano- TiO2 powder. It was found that TiO2 coating resulting from the composite powder presented much higher activity than that deposited with primary nano-particles. The better activity is attributed to the existence of large pores resulting from the stacking of composite powder, which benefits the reactants transportation through the porous coating.
Influence of Silver Doping on Photocatalytic Activity of Liquid Flame Sprayed Nanostructured TiO2 Coating
Authors: Yang G.-J. , Li C.-J. , Huang X.-C. , Wang Y.-Y. , Li C.-X. 
Published: September 2022

Abstract
Silver ion was added to liquid feedstock to deposit Ag+ doping nanostructured TiO2 photocatalytic coatings through liquid flame spraying. The coating microstructure was characterized by X-ray diffraction (XRD). The photocatalytic performance of coatings was examined by photodegradation of acetaldehyde. XRD analysis showed that the phase structure of coatings was not significantly influenced by the silver ion doping. However, a shift was found for XRD peaks of anatase TiO2. The photocatalytic activity of the TiO2 coatings was increased and then decreased with the increase of dopant concentration. The photocatalytic activity of doping coatings was higher than that of pure TiO2 coating, in spite of dopant concentration. The enhancement of photocatalytic performance of doping coatings is attributed to co-doping of Ag+ ion and metallic Ag.
Deposition and Characterization of WC–Co Coatings Prepared by Continuous- and Pulsed-Cold Spray Processes
Authors: Yandouzi M. , Sansoucy E. , Richer P. , Jodoin B. , Ajdelsztajn L. 
Published: September 2022

Abstract
Due to their mechanical properties, WC-based cermet coatings are extensively used in industrial wear-resistant applications. These coatings are usually prepared using thermal spray processes. However, due to the nature/environment of the spraying processes, the feedstock powder structure and properties suffer from severe decomposition, which subsequently degrade the performance of the coatings produced. The cold spray process appears to be a promising process alternative to preserve the properties of the feedstock powder during the coating preparation. Although, the later technique can eliminate or minimize the degradation of the material, the deposition of cermet is a complex process. In this study, nanocrystalline WC-15Co and conventional WC- 10Co4Cr coatings were deposited using both the continuous and the pulsed cold spray processes. Microstructures of the feedstock powders and the coated layers were investigated by OM, SEM and XRD. The results revealed the possibility of depositing cermet coatings onto aluminum substrates by both processes without any degradation of the phase composition of the feedstock powder. However, the continuous process experienced difficulty in depositing and building up dense coatings without major defects. Meanwhile, the new pulsed process revealed the capacity of depositing thick cermet (conventional and nanocrystalline) coatings with low porosity as long as the feedstock powder was preheated above 573 K.
Reactive Plasma Spraying of Fine Feedstock Powders for Fabrication of Nitride Ceramic Coatings
Authors: Yamada M. , Kouzaki Y. , Yasui T. , Fukumoto M. , Takahashi K. 
Published: September 2022

Abstract
Aluminum nitride (AlN) and iron nitride (Fe4N) coatings were fabricated by reactive plasma spraying using fine feedstock powders. Reactive plasma spraying, in which element particles react with surrounding active species in the plasma, enables to fabricate nitride ceramics which decompose without stable melting phase. However, it is difficult to fabricate the coatings which include higher concentration of nitride phase by reactive plasma spraying using conventional particle size of feedstock powders. Therefore, fine feedstock powders were used in order to enhance the nitriding reaction during spraying. Aluminum or iron particles were injected into Ar/N2 plasma and were deposited onto graphite substrates. It was possible not only to increase the nitride phase content in the coatings but also to densify the microstructure in both materials. Thus, it became clear that using fine feedstock powders are useful for fabrication of nitride ceramic coatings by reactive plasma spraying.
Solution Precursor Plasma Spray (SPPS) of Ni-YSZ SOFC Anode Coatings
Authors: Coyle T.W. , Wang Y. 
Published: September 2022

Abstract
Although the deposition of Ni-YSZ anodes by plasma conventional spray is more successful than other SOFC components, the large NiO and YSZ particles used for the spray process, about 50-150 microns for high porosity coating deposition, reduce the density of three phase sites for electrode reaction. In this paper, the solution precursor plasma spraying (DCSPPS) process, in which solution precursors of the desired resultant materials are fed into a DC plasma jet by atomizing gas, was used to synthesize and deposit porous Ni-YSZ composite anodes. The deposition results show that several process parameters have significant effects on the microstructure and phase composition of the deposited material. The deposits were composed of tower-like, irregularly shaped agglomerates and splats. The sizes of the agglomerates increase with the decrease of the plasma torch power and most are not completely molten during the impact. The amount of splats is proportional to the power and they are much smaller than the agglomerates in volume. After heat treatment to reduce the NiO present in the as deposited coatings, the coatings were found to contain small spherical YSZ particles about 0.5 micrometers in diameter distributed in a continuous Ni matrix. The coatings have 29%-51% porosity depending on the process parameters.
Experimental and Numerical Studies of Plasma Forming Process Parameters Effect on Optimum Particle Impact Locations
Authors: Zhang W. , Sampath S. , Zheng L.L. 
Published: September 2022

Abstract
This paper investigated the role of particle injection on inflight particle behavior and its coupling effect on plasma plume in an external orthogonally injected air plasma spray system as well as effects of primary, secondary and carrier gases on in-flight particle status through both experiments and simulations. Diagnostic sensors such as In-flight Particle Pyrometer (IPP) and Spray Position Trajectory (SPT) have been used to obtain the plume characteristics and ensemble temperature, while DPV-2000 was used to measure the distributions of individual particle status such as temperature, velocity and size at the maximum particle flux point. Three-dimensional simulations have been carried out for the corresponding experimental conditions to examine the effects of in-flight particle heating on the plasma plume and in-flight characteristics at different spray distances. Both experiment and simulation results show that particle temperature and velocity will initially increase with plume angle and then decrease after reaching a maximum value for different combination of process parameters at the same plume angle. Theoretical analysis shows strong dependence of the plume angle on the velocity ratio of vertical component from the carrier gas to the horizontal one from primary and secondary gas at their respective nozzle exits. This study enables a better understanding of influence of plasma forming and stabilizing parameters on the particle in-flight characteristics.
Microstructure Control of NiO(Graphite)/8YSZ SOFC Anode Coatings by Atmospheric Plasma (APS)
Authors: Kwon O.C. , Lee C. , Hwang S.Y. 
Published: September 2022

Abstract
Anode layer, as the main site for the reaction of fuel and removal of byproducts, plays an important role in anode-supported solid oxide fuel cell (SOFC). Generally, high electrical conductivity and gas permeability (porosity) of the anode materials are required to reduce the polarization loss of SOFC. This study focuses on the manufacturing of porous anode layers for SOFC. The NiO/8YSZ cermets anode coatings are fabricated by atmospheric plasma spray (APS) using the blended powder of nickel coated graphite (Ni-graphite) after oxidation (NiO-graphite) and 8mol%Y2O3-stabilized ZrO2 (8YSZ). To increase the porosity and the uniformity of the coatings, nickel coated graphite with low density is used as the starting feedstock instead of the conventional pure Ni powder. To balance the conductivity (Ni), porosity (graphite), and structural stability (8YSZ) of the coatings, the effects of process parameters such as hydrogen (H2) gas flow rate, spraying distance, and pore formation precursor (carbon black addition) on the microstructures of resulting coatings by APS are investigated. The results show that the NiO/8YSZ anode coatings with high conductivity, structural stability and porosity could be deposited by APS with moderate H2 gas flow rate and short distance. The microstructure of the coating is mainly associated with the degree of melting of impact particles.
Operational Limitations of the iPro-90 Plasma Spray Gun
Authors: Rusch W. 
Published: September 2022

Abstract
Plasma spray torches for spraying internal diameters have typically been limited to 40 kW in the past. A new internal plasma spray torch has been developed with an operational power limit above 90 kW. This high power torch was primarily developed to decrease the spray time required to apply coatings to large inside diameters such as land based gas turbine components. This paper explores the factors effecting the operation of this torch as well as the functional limits of its operation. The factors investigated are gas flow, gas ratios, current, voltage, water flow, and water temperature. Thermal efficiency and plasma enthalpy are presented.
Evaluation of Tungsten Carbide Coatings Sprayed with High Velocity Plasma Using a Process Map
Authors: McCullough R. , Molz R. , Hawley D. 
Published: September 2022

Abstract
Process mapping is an ideal method for tracking coating characteristics in the thermal spray process. With the increased utilization of in-flight particle diagnostic tools in recent years it is now possible to quickly and effectively characterize inflight powder particle properties. With industries' increasing understanding of the relationship of these properties and coating characteristics, it is now possible to rapidly understand the implications of in-process changes with respect to coating performance. This paper is an exploratory exercise that describes the utilization of process mapping of in-flight particle velocity and temperature characteristics to optimize tungsten carbide (WC) coatings sprayed with a High Velocity Plasma torch (HVP). Key performance factors of WC coatings include high inherent hardness, low porosity and neutral to compressive stress conditions. The combination of these factors all contribute to the coatings' overall success in it's intended application and elude to its toughness, wear resistance, corrosion resistance and general ability to protect the required components. Presently, the High Velocity Oxygen Fuel (HVOF) and High Velocity Liquid Fuel (HVLF) combustion processes are the favored method of applying dependable and commercially viable WC coatings that meet all of these criteria.
Titanium Nitride Spraying Using Supersonic Nitrogen and Nitrogen/Hydrogen-Mixture Plasma Jets in Thermodynamic and Chemical Nonequilibrium State
Authors: Tahara H. , Ando Y. 
Published: September 2022

Abstract
In low-pressure plasma spraying, a plasma jet generator with a supersonic expansion nozzle is useful for spray coating hard and large-area films adhering strongly to substrates. In the expansion nozzle, the pressure and the electron density drastically decrease downstream, and therefore the plasma is in thermodynamic nonequilibrium state. Additionally, the supersonic expanding plasma jet is expected to be in chemical nonequilibrium state in which excited plasma particles are carried downstream in chemically-active state. In this study, titanium nitride (TiN) reactive spraying was carried out under a low-pressure environment using a DC arc plasma jet generator with a supersonic expansion nozzle. Titanium powders were injected using a hollow cathode with argon gas, and the plasma gas was nitrogen or nitrogen and hydrogen mixture. Microstructure and properties of the coatings were examined using scanning electron microscope (SEM) and X-ray diffraction (XRD). A dense and high-quality TiN coating with a Vickers hardness of 2000 was formed at a low substrate temperature of 700 °C with a low input power of 5.3 kW. All results showed that the supersonic plasma jet in thermodynamic and chemical nonequilibrium state had high potentials for reactive spraying.
Fuzzy Logic Analysis of Alumina–Titania Deposition Yield During APS Process
Authors: Kanta A.F. , Montavon G. , Planche M.P. , Coddet C. 
Published: September 2022

Abstract
The behavior modeling of Atmospheric Plasma Spray (APS) process requires a global approach which considers interrelated non-linear relationships between coating characteristics / properties in-service and process parameters (power, feedstock injection, kinematics, etc.). Such an approach would permit to reduce the development costs. To reach this objective, the knowledge of the interactions between process parameters plays a relevant role in the optimization. This work intends to develop a behavior model based on fuzzy logic concepts. Here, the model considers the deposition yield as the result of the process and it establishes relationships with power process parameter (arc current intensity, plasma gas total flow rate, hydrogen content) on the basis of fuzzy rules. The model hence permits to discriminate the role and the effects of each power process parameters. The modeling results are compared to experimental data. The specific case of the deposition of alumina-titania (Al2O3-TiO2, 13% by weight) by Atmospheric Plasma Spraying (APS) is considered.
Submicron α-Fe/Nylon-12 Composite Absorber Coatings Produced by Low Temperature High Velocity Air Fuel Spray Technique
Authors: Yuan X. , Wang H. , Hou G. , Zha B. , Jiang L. 
Published: September 2022

Abstract
In this paper, submicron α-Fe/nylon-12 microwave absorbing composite coatings were deposited by a Low Temperature High Velocity Air Fuel (LTHVAF) spraying technique. The microstructure and the electromagnetic parameters of coatings and powders were tested. The coatings are dense and have low porosity. The microwave reflectivity coefficient of the coatings was calculated with permeability and permittivity of the powders. It shows that there is a relationship between the mass fraction of composite powders and microwave absorption ability of coatings. At the threshold value, the composite coatings can absorb microwave strongly. When the coatings thickness increases, the minimal reflectivity coefficient moves to the low microwave frequency. There exists an appropriate coatings thickness in order to optimize the absorption of the microwave energy. The mass fraction and the thickness can affect the performance of composite absorber coatings.
Sliding Wear Properties of HVOF Thermally Sprayed Nylon-11 and Nylon-11/Ceramic Composites on Steel
Authors: Jackson L. , Ivosevic M. , Knight R. , Cairncross R.A. 
Published: September 2022

Abstract
The high velocity oxy-fuel (HVOF) combustion spray process has previously been shown to be a successful method for depositing pure polymer and polymer/ceramic composite coatings. Polymer and polymer-ceramic composite particles have high melt viscosities and require the high kinetic energy of HVOF in order to generate sufficient particle flow and deformation on impact. One of the goals of reinforcing polymer coatings with particulate ceramics is to improve their durability and wear performance. Composite coatings were produced by ball-milling 60 µm Nylon-11 together with nominal 10 vol.% of nano and multi-scale ceramic reinforcements and HVOF spraying these composite feedstocks onto steel substrates to produce semi-crystalline micron and nano-scale reinforced coatings of polymer matrix composites. The room temperature dry sliding wear performance of pure Nylon-11, Nylon-11 reinforced with 7 nm silica, and multi-scale Nylon-11/silica composite coatings incorporating 7 to 40 nm and 10 µm ceramic particles was determined and compared. Coatings were sprayed onto steel substrates, and their sliding wear performance determined using a pin-on-disk tribometer. Coefficient of friction was recorded and wear rate determined as a function of applied load and coating composition. Surface profilometry and scanning electron microscopy were used to characterize and analyze the coatings and wear scars.
Properties of Nanostructured WC-12Co Coatings Sprayed by HVOF
Authors: Zhao H. , Ding Z. , Zhang Y. , Wang Q. 
Published: September 2022

Abstract
In the present paper, nanostructured, multimodal and conventional WC-12Co cermet coatings were deposited by HVOF and the properties and structures of the coatings such as microhardness, microstructure, phase composition and wear resistance were compared. Finally the wear failure mechanisms of WC-12Co coatings were explored by XRD and SEM analysis. Research results show that microstructures of nanostructured and multimodal WC-12Co coatings deposited by HVOF are dense with little porosity, and their microhardness values are obviously higher than conventional WC-12Co coating. As well, it was found that nanostructured and multimodal WC-12Co coatings exhibited better erosion and adhesive wear resistance in comparison with conventional coating, and nanostructured WC-12Co coatings possessed the best erosion resistance properties at large impact angles and adhesive wear resistance. At small impact angles, WC-12Co coatings deposited by HVOF demonstrate better erosion wear resistance than at large impact angles and the erosion wear performance at 30º is more than 1.7 times higher than at 90º. In comparison with conventional WC-12Co HVOF sprayed coating, the adhesive wear resistance of the nanostructured and multimodal coatings is respectively enhanced by above 70% and 50%. Testing results also show that although decarburization of WC occurred during spraying multimodal and nanostructured WC-12Co powders, the decarburization of WC for the nanostructured powder was more severe.
Spheroidization of Bioceramic Powders in a Radio Frequency Plasma
Authors: Xu J.L. , Khor K.A. , Kumar R. 
Published: September 2022

Abstract
Inductively coupled radio frequency (RF) plasma spraying, powered by high-frequency oscillating electrical current, performed an important role in fine powder manufacture. It was used in the present study to prepare fine spherical bioceramic powders of hydroxyapatite (HA) whose chemical composition similar to those of natural bone. The as-sprayed powders consisted of both micron-sized spherical particles and nano-sized particles. In addition to the spheroidization effect, rf plasma treatment led to the decomposition of HA into secondary calcium phosphate phases including tri-calcium phosphate (TCP), tetra-calcium phosphate (TTCP) and calcium oxide (CaO). The microstructure investigation showed that the spheroidized particles were either fully dense or hollow structure with a shell. The reason for the formation of hollow spheres was contributed to the higher density of the solidifying surface layer compared with the molten phase during solidification.
Evaluation of Residual Stress for Plasma-Sprayed Plate Using Deflection Measurement
Authors: Itoh Y. , Suyama S. 
Published: September 2022

Abstract
The evaluation of residual stress distributions of a thermal sprayed plate is an important problem from the viewpoint of preventing the cracking and/or delamination of coatings. Though the well-known method for estimating the residual stress has been widely used based on Stoney’s type equations, the accuracy of estimation has not always been made clear. In this paper, accurate estimation of residual stresses of coated components using finite element analysis was implemented and polynomial expression of the relationship between residual stress and deflection is proposed. It was confirmed that the residual stress estimated by the newly proposed equation was in good agreement with the experimental results measured by X-ray diffraction method in case of a CoNiCrAlY coating applied on an IN738LC substrate using plasma spraying in air atmosphere.
Influence of Oxidation Phenomenon on Tribological Behaviour of Plasma Spray Coating
Authors: Stihle A. , Liao H. , Planche M.P. , Coddet C. , Kenzari S. 
Published: September 2022

Abstract
The friction behaviour of steel coating deposited on aluminium using a plasma spray process was investigated in this study. Various parameters and spraying atmospheres were varied for forming different coating microstructures, phases and density values. Addition of oxide phase is known to enhance the friction behaviour and wear resistance. In order to see the friction behaviour of steel coating without oxide, deposition was performed with a shroud that maintained inert gas condition around the plasma. Deposition was also performed under oxygen in order to maximize the oxidation. It is found that coatings contain steel and oxides (FeO, Fe3O4). Tribological tests were performed using a ball on disc configuration with a steel ball and WC/Co ball. The coating friction behaviours are completely different for different balls. The worn surface and the ball were characterized with optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The present study focuses on the relationship between the iron oxide formed or not during spaying, the injection parameters into the plasma jet and the microstructural characteristics and the tribological behaviour of the resulting coatings.
Effect of Powder Injection Location on Ceramic Coatings Properties When Using Plasma Spray
Authors: An L.T. , Gao Y. 
Published: September 2022

Abstract
The effect of powder injecting location of the plasma spraying on spraying properties was studied. Three different powder injecting methods were applied in the experiment. In the first method, the particles were axially injected into the plasma flow from the cathode tip. In the second method, the particles were radially injected into the plasma flow just downstream of the anode arc root inside the anode nozzle. In the third method, the particles were radially injected into the plasma jet at the nozzle exit. The alumina particles with a mean diameter of 20µm were used to deposit coatings. Spraying properties such as the deposition efficiency, the melting rate of the powder particles, and the coating quality were investigated. The results show that the spraying with axial particle injecting can heat and melt the powder particles more effectively, produce coatings with better quality, and have higher deposition efficiency.