bluuebunny/crossref_metadata_2025_split huggingface dataset:
The High Temperature Erosion/Corrosion Behavior of Industrial Thermally Sprayed Coatings
Authors: Heath G.R. , Kammer P.A. , Stack M.M. 
Published: May 2021

Abstract
There are numerous industrial applications where materials are subjected to simultaneous high temperature oxidation/corrosion and wear (such as erosion). This combination often leads to accelerated degradation. Specific industries include: chemical, waste incineration, power generation and paper/pulp with typical applications including boilers and cyclones. Previous studies have established wrought material compositions and microstructures which can resist these environments. In searching for cost-effective industrial solutions, surface coating via thermal spray becomes attractive. However, the microstructural complexity of such coatings can make the simple extrapolation of bulk material behavior to these coatings dangerous. If these coatings are to be used more widely, a greater understanding of their high temperature erosion/corrosion behavior and the influence of coating process is required. A range of Fe-and Ni-based alloys and thermal spray techniques were studied under various high temperature erosion/corrosion conditions. The critical erosion parameters of impact angle (30° to 90°) and temperature (up to 550°C in air) have been studied in an atmospheric fluidized bed test rig environment, using Al2O3 erodent at a typical impact velocity of 4m/sec and conventional high temperature erosion test equipment. The important microstructural and mechanical features of the coatings and the effect of the thermal spray process are discussed in terms of their high temperature degradation mechanisms.
Ultrasonic Application of Thick Metallic Coatings
Authors: Legoux J.-G. , Jen C.-K. 
Published: May 2021

Abstract
Ultrasonic propagation characteristics in thermal spray materials are affected by the complex microstructures of these coatings. Factors such as oxide stringers, porosity, splat size and morphology can all affect wave propagation. This dependence causes many concerns when one performs nondestructive evaluation of such coatings. However, we find that the unique properties of thermally sprayed coatings can be used for the fabrication of the cladding region of clad solid ultrasonic wave guides (or buffer rods) consisting of a core and a cladding. These wave guides are used as precious quality control devices for on-line monitoring of industrial materials processes. This paper is devoted to the tailoring of the ultrasonic behavior of metallic coatings produced by arcspraying. Experimental results show that by a proper control of the core-cladding system it is possible to minimize ultrasonic spurious signals occurring in a clad wave guide while the tailoring of the splat morphology, intersplat oxidation and porosity enable the appropriate ultrasonic absorption within the coating. The unwanted spurious signals are normally generated at the periphery of the core. Examples of the use of thick (up to 5 mm) stainless steel or bronze coatings as claddings on steel, aluminum or zirconium rods in order to provide good ultrasonic wave guides are given. Compared to a conventional non-clad rod the signal to noise ratio of such clad rods has been improved by more than 40 dB due to the reduction of the spurious signals. The potential applications of these clad buffer rods for thickness measurements and in-situ monitoring of materials at elevated temperatures are demonstrated.
Improved High Temperature Iron Oxide Based Tribological Coatings
Authors: Kleyman A. , Kamo L. 
Published: May 2021

Abstract
The experimental results of developing tribological surface coatings for high temperature application are presented. The primary focus of this work was in the area of high output advanced, low heat rejection (LHR) diesel engines, where high temperature lubrication between the piston ring and the cylinder liner wall surface is essential. The target temperature focused upon in our research is an operating top ring reversal temperature of approximately 1000° F. The technology developed typically involves treating a porous thermal spray coating with chemical binders improving coating strength and integrity and eliminating open porosity to form an almost monolithic appearing coating. The effectiveness of the densification through the coating thickness was studied. It has been shown that densification process improves mechanical properties and dramatically extends coating wear resistance. Good results were obtained using densified plasma spray Iron oxide (hematite) for a cylinder liner coating versus plasma sprayed Tribaloy T 800 for piston ring. Single Cylinder LHR engine test successfully demonstrated the feasibility of this tribological pair for the possible future applications.
Behavior of Some Tungsten Carbide Coatings in Molten Zinc
Authors: Stavros A.J. 
Published: May 2021

Abstract
Two different W-Co-C powders were used in three deposition devices, the Super D-Gun, Jet Kote, and JP-5000 to produce coatings for laboratory immersion tests in molten zinc and %55Al-Zn. Resistance was evaluated as time to failure. Scanning electron microscopy and X-ray diffraction were used to characterize the structures ssid failure mechanism. All coatings were found to fail when the molten metal breached the coating thickness at weak spots and spread out over the underlying interface to lift the coating away from the underlying 316L substrate. These weak spots were "pits" on one Super D-Gun coating (the most resistant coating) and cracks on all the other coatings. No diffusion of zinc through the tungsten carbide coatings was observed.
Cavitation Erosion of HVOF Coatings
Authors: Schwetzke R. , Kreye H. 
Published: May 2021

Abstract
The proposed paper reports a series of experiments to investigate the cavitation erosion mechanism of HVOF coatings. Vibratory cavitation erosion tests according to ASTM G 32 have been carried out with several HVOF coatings including cermets, oxides and metallic alloys. The steady state erosion rate for each coating was determined and the effect of coating composition and microstructure on the erosion rate was investigated. The morphology and microstructure of the various coatings before and after cavitation testing were analyzed by means of light optical and scanning electron microscopy in order to study the erosion mechanism. The results demonstrate that HVOF coatings of NiCrFeBSi, WC-17Co, Cr3C2-25NiCr and Cr2O3 can exhibit a rather high resistance against cavitation erosion and should be considered for application as a protective surface layer against cavitation. Furthermore, it is shown that cavitation testing can provide a useful tool to study and characterize the bond strength between individual splats as well as the brittleness of the individual phases present in the coating.
Titanium Carbide in Wear Resistant Coatings
Authors: Vitiaz P. , Verstak A. , Azarova T. , Talako T. , Lugscheider E. 
Published: May 2021

Abstract
The poblems of metal-titanium carbide coatings processing by air, low pressure and underwater plasma as well as high velocity oxygen fuel spraying are under consideration. Among the different methods of metal-TiC powders production, like mixing of carbides with scale structure metals, agglomeration with binders, a matter of special interest is the high temperature synthesis of TiC in presence of metallic alloy. The characteristic features of these materials include the carbide phases forming, their bonding with the alloy and reactions during spraying, grain size and their distribution, alloy behavior during synthesis and spraying. Finally, the abrasive wear and erosion resistance of Al-Si/TiC, Fe-Cr/TiC and Ni-Cr/TiC coatings is analyzed.
Applying Thermoplastic Powder by Flame Spraying on Various Types of Substrates
Authors: Dominguez R. , Monerie F. , Vardelle A. , Fauchais P. 
Published: May 2021

Abstract
Polymeric coatings are now widely used for their corrosion resistance, low friction coefficient against many materials, decorative properties but also, when doped with ceramic particles, their protection against slipping and their good erosion resistance. Compared to traditional means of deposition, flame spraying in controlled atmosphere extends the scope of their applications either for shapes that can be coated or for site deposition. The materials chosen for spraying were Rislan, Gotalene and Tefzel. In this paper are presented the flame spraying technique which was used and the parameters controlling particles melting as well as, the substrates on which coatings were achieved (metals, woods, concretes, ceramics...) and their preparation. A few applications are then described with for example coatings reinforced by ceramic particles against slipping in wet or greasy area.
Acoustic Emission Studies of Thermal Barrier Coatings during Cyclic Four Point Bend Tests
Authors: Voyer J. , Gitzhofer F. , Boulos M.L. , Dionne J. 
Published: May 2021

Abstract
In this study, Acoustic Emission (AE) signals are used to monitor the degradation of plasma sprayed Thermal Barrier Coatings (TBC) using cyclic four point bend tests. Signal analysis both in time and frequency domains is carried out in order to identify the key parameters which can be used to classify the acoustic emission signals as a function of the damage mechanisms. This classification offers a mean of prediction of the long-term behavior of the thermal barrier coating based on the acoustic emission signal signature at the early stages of bench testing. The samples consist of a Nickel-based alloy blade coated with a duplex TBC made of a 150 μm thick bond coat covered with a 300 μm thick partially-stabilized zirconia coating. Tests were performed on unnotched and perpendicularly notched samples in order to discriminate the AE from perpendicular cracks. Two broadband transducers are used for acquisition of acoustic emission signals. Measuring the time between signal detection by each of the two transducers provides a means of determination of the location of the source of the acoustic signals. A classification of the signals based on their energy and their maximum peak frequency is presented. A comparison is made between the degradation mechanisms of TBC under thermal cycling conditions that were presented elsewhere (1) and the results of four point bend tests presented here.
Plasma Processing of Functionally Graded Materials: Diagnostics and Characterization
Authors: Smith W. , Jewett T.J. , Sampath S. , Berndt C.C. , Herman H. , Fincke J. , Wright R.N. 
Published: May 2021

Abstract
Functionally graded materials (FGMs) offer solutions to such engineering problems involving multi-layer systems with large differences in CTE, i.e. thermal barrier coatings, by allowing for a continuous change in the properties over a defined distance, thus minimizing sharp interface effects. By its nature, plasma spraying is well suited to the fabrication of FGMs. However, in order to achieve optimal performance from the material it is necessary to ensure the FGM is uniform in its compositional variation. The deposition efficiency of the particulate species as well as their trajectories will determine the degree of homogeneity of the FGM. It is therefore important that the inter-relationships between the particle size distributions, injection orientation and feed rates are determined. Towards this end, a series of investigations have been carried out to determine the effects of injection orientation on the particle segregation. Analysis of the particle segregation as a function of particle size distribution was then examined in the formation of FGMs. The results indicate that optimal deposition occurs when the various particle species trajectories converge as they approach the substrate.
Al-SiC Metal Matrix Composite Coatings by Plasma Spraying
Authors: Ghosh K. , Troczynski T. , Chaklader A.C.D. 
Published: May 2021

Abstract
The use of aluminum in the automobile engines and other critical parts require a superior surface property of the same. This has led to the development of plasma sprayable surface coatings in the automotive components. To impart the maximum bonding strength, along with hardness to the coatings, an aluminum based composite (Al-SiC) was chosen to be the most suitable. The presence of a hard second phase within a soft matrix improves the wear resistance of the material. The metal matrix composite powders were made by mechanical alloying of 6061 aluminum alloy (particle size 40-60 μm) along with fine SiC particles (≈ 8μm). Content of SiC was varied from 20-75vol% the balance being aluminum alloy. An organic material was used as Process Control Agent to optimize distribution of ceramic within metal matrix. The coatings obtained by plasma spraying the powders were characterized for their microstructure, adherence, wear and other physical properties.
Self-Lubricating Composite Plasma Sprayed Coatings
Authors: Niebuhr D. , Scholl M. , Clayton P. 
Published: May 2021

Abstract
Composite self-lubricating coatings were developed using high-energy plasma spraying (HEPS). These coatings would be potentially used in high contact pressure rolling/sliding systems. The coatings are based on a steel coating deposited by high energy plasma spraying using wire feedstock. Solid lubricants such as graphite and soft metal were investigated. Twin roller rolling/sliding tests were performed at 5% and 35% creep and contact loads of 700 N to 1700 N on a 5 mm contact face. Reduced friction, compared to a steel coating-steel or 1080 wrought steel couple was observed under these rolling-sliding contact conditions.
Properties of a Thermal Barrier Coating Fabricated by R.F. Plasma Spraying
Authors: Crabos F. , Monge-Cadet P. , Lucchese P. , Blein F. , Rigal E. 
Published: May 2021

Abstract
A P.S.Z. coating elaborated by r.f. plasma spraying was studied and compared to industrial arc plasma-sprayed P.S.Z. coatings to evaluate the quality of the corresponding thermal barrier coating system for gas turbine applications. One commercial ZrO2 - 8% Y2O3 powder was sprayed with two industrial d.c. torches (7MB and F4) and one r.f. plasma torch (Tekna PL50). Physical properties such as density, porosity and thermal diffusivity were measured on the three types of P.S.Z. coating. The microstructure and quantitative phase analysis were respectively investigated by S.E.M. and X-Ray diffraction. The burner rig tests on the T.B.C. systems showed that the thermal shocks resistance on the r.f. coating was at least the same as the others. Induction plasma spraying gave a high deposit efficiency (around 80%) and a P.S.Z. coating with very interesting thermal properties. All these facts demonstrate that r.f plasma spraying can be a competitive process to produce high quality thermal barrier coatings.
Phase Formation during In-Flight Treatment of MoSi2 Powders in an R.F. Induction Plasma
Authors: Fan X. , Ishigaki T. 
Published: May 2021

Abstract
The in-flight modification of MoSi2 powders has been carried out by using an Ar-H2 induction plasma. Reactor pressure, powder feed rate and plate power level were taken as the experimental parameters to alter the thermal history of the injected powder particles. Metastable hexagonal structure of P-MoSi2 is the major phase observed in the induction plasma treated molybdenum disilicide powders, the stable phase of tetragonal structure of α-MoSi2 usually retains approximately 30 wt.%. Following the change in experimental condition and the deviation from stoichiometry in raw materials, low silicides, Mo5Si3 and Mo3Si, and free Si were observed. The formation of these phases are explained in terms of metastable eutectic reaction during rapid solidification processing. The relationship between the quantities of all these phases and the experimental conditions has been discussed.
The Characteristics of Diamond Film Deposited by Magnet-Enhanced Plasma Jet CVD
Authors: Zhou K. , Dair M. , Wang D. , Han P. , Feng B. 
Published: May 2021

Abstract
A diameter of 30 mm polycrystalline diamond film has been deposited by magnet-enhanced DC plasma jet CVD. The diamond film was characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and surface profilograph. Results reveal that under the same depositing parameters, magnetic field can increase purity of diamond film, improve thickness uniformity of diamond film, but no influence on crystal perfection and size of microcrystal of diamond film. A discussion on magnetic effect is presented.
Effect on Reverse Transferred Arc Treating on Bonding Strength in Low Pressure Plasma Spraying
Authors: Honda K. , Chida I. , Fuse T. , Murakami T. , Kobayashi K.F. 
Published: May 2021

Abstract
Both bonding strength of coating to substrate in low pressure plasma spraying and the effect of reverse transferred arc treating before spraying are studied in this paper. It is difficult to obtain the bonding strength precisely in low pressure plasma spraying by standard testing methods, such as, ASTM Standard C633-79 and JIS H8666-80. Therefore, for the bonding strength test rather than using a conventional adhesive, we believe a vacuum brazing process using Ag-Cu-In-Ti active filler metal at 1023 K should be used. We have also confirmed the practicality of this step. By the above test method, it has been proven that the bonding strength of low pressure plasma sprayed coating is over 100 MPa. Also, that reverse transferred arc treating after blasting enhances the bonding strength of low pressure plasma sprayed coating. It is also believed that the projections formed on the substrate surface by reverse transferred arc treating are buried into the coating and perform the pile effect.
Iron-Based Deposits Produced by High-Throughput Water Stabilized Plasma
Authors: Dobler K. , Branco J.R.T. , Sampath S. , Berndt C.C. , Herman H. , Chráska P.J. 
Published: May 2021

Abstract
Iron-based thermal spray deposits have been used for reclamation of machine components and wear resistance. Current thermal spray processes can be used to spray deposits a few millimeters thick at rates of 3 to 10 kg/hr. With a throughput over 100 kg/hr for metals, the Water Stabilized Plasma torch enables cost-effective processing of very thick (&gt;1 cm) deposits at very high rates. However, limited information exists in the literature on the ability of this technology for deposition of oxygen sensitive metals. In this investigation, iron-based coatings were produced with the water stabilized plasma system. The deposits sprayed in air and with an inerting shroud were evaluated using x-ray diffraction, light microscopy, oxygen analysis and microhardness in an effort to understand the processing effects on microstructure and properties.
Particle Size Effects on Chemistry and Structure of Al-Cu-Fe Quasicrystalline Plasma Sprayed Coatings
Authors: Sordelet D. , Besser M. 
Published: May 2021

Abstract
A brief study was performed to examine the influence of starting powder composition, starting powder particle size and spraying environment on the chemistry, phase assemblage and porosity of Al-Cu-Fe plasma sprayed coatings involving a quasicrystaliine phase. It was found that a loss of Al during spraying results from the extremely low thermal conductivity of the quasicrystaliine phase in the starting powders. This loss changes the bulk composition of the deposited coating and partially controls the phases that develop. Smaller starting powder particles tended to lose more Al and, therefore, form less of the quasicrystaliine phase. Larger starting powder particles did not lose Al to the same degree, and produced coatings with more of the quasicrystaliine phase. However, these powders produced coatings also had a higher amount of porosity.
Effects of Pressure Deposition on Plasma Jet and Coatings Microstructure
Authors: Valente T. , Bertamini L. , Tului M. 
Published: May 2021

Abstract
Pressure inside the spray chamber plays a key role during coatings manufacturing by thermal spraying and coating properties can be strongly affected by the selected pressure value. Spraying at low pressure results in a longer plasma jet length, higher particle velocity, lower coating porosity and higher purity and phase stability. For what concerns plasma-particle interactions, a reduction of pressure value drastically decreases heat transfer towards particles, therefore high power plasma equipment must be used to achieve a suitable melting degree of sprayed powders. Effects of low pressure values are well known, but few investigation have been carried out on effects of pressure for values higher than 1,000 mbar. In this paper a preliminary evaluation of pressure effects on plasma jet modifications, particle velocity and coatings microstructure is presented. By using the very innovative CAPS (Controlled Atmosphere Plasma Spraying) system, Ni-20%Al powders were sprayed at different pressure values, up to 3,600 mbar. The length and width of the visible part of the plasma jet was measured and controlled. Average particle velocity was also evaluated as a function of pressure. Coatings, manufactured on stainless steel substrates, were characterized by means of scanning electron microscopy and energy dispersive spectroscopy, x-ray diffraction and Vickers microhardness measurements. Results indicate that the higher the spraying pressure the lower the plasma jet length and particle velocity; but also a lower selective evaporation of aluminum and higher microhardness values were observed.
Ceramic Impregnation of Plasma Sprayed Thermal Barrier Coatings
Authors: Kathikeyan J. , Berndt C.C. , Ristorucci A. , Herman H. 
Published: May 2021

Abstract
Reducing the pore size and pore volume can lead to improved mechanical properties and enhanced corrosion resistance of plasma sprayed thermal barrier coatings. In this work, plasma sprayed 8 wt.% yttria stabilized zirconia coatings were removed from the substrate and machined to obtain 25x5x1 mm test specimens. These specimens were vacuum impregnated with alumina sol, calcined at 873 K for an hour and then heat treated at 1273 K for an hour to produce ceramic impregnated specimens. As-sprayed and impregnated specimens were investigated using optical microscopy, XRD, SEM, mercury intrusion porosimetry and electron microprobe analysis. This technique can impregnate the entire thickness of the specimens. Pores in the as-sprayed specimens were impregnated with α alumina grains, resulting in microstructural variations and reduction of the size and volume of the specimen pores.
Computational Fluid Dynamics Analysis of a Wire-Feed, High-Velocity Oxygen-Fuel (HVOF) Thermal Spray Torch
Authors: Lopez A.R. , Hassan B. , Oberkampf W.L. , Neiser R.A. , Roemer T.J. 
Published: May 2021

Abstract
The fluid and particle dynamics of a High-Velocity Oxygen-Fuel Thermal Spray torch are analyzed using computational and experimental techniques. Three-dimensional Computational Fluid Dynamics (CFD) results are presented for a curved aircap used for coating interior surfaces such as engine cylinder bores. The device analyzed is similar to the Metco Diamond Jet Rotating Wire (DJRW) torch. The feed gases are injected through an axisymmetric nozzle into the curved aircap. Premixed propylene and oxygen are introduced from an annulus in the nozzle, while cooling air is injected between the nozzle and the interior wall of the aircap. The combustion process is modeled using a single-step finite- rate chemistry model with a total of 9 gas species which includes dissociation of combustion products. A continually-fed steel wire passes through the center of the nozzle and melting occurs at a conical tip near the exit of the aircap. Wire melting is simulated computationally by injecting liquid steel particles into the flow field near the tip of the wire. Experimental particle velocity measurements during wire feed were also taken using a Laser Two-Focus (L2F) velocimeter system. Flow fields inside and outside the aircap are presented and particle velocity predictions are compared with experimental measurements outside of the aircap.