bluuebunny/crossref_metadata_2025 huggingface dataset:
PIV Measurements of Metallic Powders Produced by Liquid Metal Atomization Using de Laval Nozzle
Authors: Khatim O. , Planche M.P. , Dembinsky L. , Coddet C. , Bailly Y. , Guermeur F. , Girardot L.
Published: September 2022

Liquid metal atomization using de Laval nozzle is an established technique for producing fine (< 100 μm) metal powders for a lot of industrial applications. This process offers a variety of advantages as spherical morphology or low consumption of inert gas for example. Despite its widespread uses, however, the relationships among gas dynamics melt nozzle and de Laval nozzle diameters, processing parameters, and particle size remain defined. As a result, efforts to reduce powder costs by improving particle size control and energy efficiency remain hindered. Then, the optimization of this process is a great challenge. This experimental study examines the atomizing spray behavior depending on the process parameters. Experiments were conducted on copper (at 99.9%). Particle Image Velocimetry technique was implemented in the atomization chamber and measurements were performed to characterize in velocity the atomized droplets. The PIV system was placed in such a way that the atomization zone, comprised between 50 and 110 mm downstream the de Laval nozzle exit, can be monitored by the camera. The evolutions of the particle velocity and particle sizes were finally analyzed versus the working conditions.
Relations between in Flight Particle Characteristics and Coating Properties by HVOF-Spraying
Authors: Tillmann W. , Vogli E. , Hussong B. , Kuhnt S. , Rudak N.
Published: September 2022

Thermal spraying technology still suffers from a lack of reproducibility due to uncontrollable factors during the process. Current methods of process control by means of observing process parameters like gas- and powder flow are insufficient to guarantee a constant quality of coatings, while a direct analysis of the deposited layer is time- consuming and can only be conducted after the process. Furthermore, recently developed mathematical models which correlate process parameters to coating properties are not applicable for all materials. As the particles’ behavior during the process affects the coating properties, a direct process control by the observation of the particles seems expedient. This method is applicable on running processes and thus avoids defective production. In this study, HVOF spraying experiments were conducted. The in-flight particles’ behavior was investigated using an optical diagnostic system, while coating properties were analysed by metallographical methods.
Consolidation of Al2O3/Al Nanocomposite Powder by Cold Spray
Authors: Poirier D. , Legoux J.-G. , Drew R. A. L. , Gauvin R.
Published: September 2022

While the improvement in mechanical properties of nanocomposites makes them attractive materials for structural applications, their processing still present significant challenges. In this paper, cold spray was used to consolidate Al2O3/Al nanocomposite powders obtained from mechanical milling. The microstructure and nanohardness of the feedstock powders as well as of the resulting coatings were analysed. The results show that the large increase in hardness of the Al powder after mechanical milling is preserved after cold spraying. Good quality coating with low porosity is obtained from milled Al. However, the addition of Al2O3 to the Al powder during milling decreases the powder nanohardness. This lower hardness is attributed to non-optimised milling parameters for proper Al2O3 embedding and dispersion in Al and results in a lower coating hardness compared with the milled Al coating. The coating produced from the milled Al2O3/Al mixture also shows lower particle cohesion and higher amount of porosity. The overall results are promising and it is believed that an optimization of Al milling with Al2O3 will allow production of sound coatings with improved hardness.
Adhesion of YSZ Nanostructured Coating on Haynes 230 Substrate
Authors: Vert R. , Meillot E. , Vardelle A. , Mariaux G. , Dublanche-Tixier C. , Chicot D.
Published: September 2022

The gas-cooled fast reactor is a 4th generation nuclear reactor currently under development. Its design concept requires protective coatings able to operate at 850°C and protect the underlying structure in case of extreme cases, where the functional temperature can increase up to 1250°C and there is depressurization from 70 bars to atmospheric pressure. The parts to be covered are made in 1-mm thick materials resistant to heat and erosion with high mechanical properties at high temperatures, such as the Haynes 230 nickel-based alloy. In this study, the potential of the suspension plasma spraying technique for forming the first layers of a ceramic coating on smooth 1-mm thick Haynes substrate was explored. In order to meet these specifications, the coating material selected was partially stabilized zirconia of standard composition (8 mol.% Y2O3-ZrO2).
Microstructure of Thermal Sprayed Silicon Coatings using Various Particle Sizes and Spray Conditions
Authors: Jackson D.D. , Sereda M. , Gansert R.
Published: September 2022

Silicon based coatings are showing great promise for power applications in the semiconductor, target, and solar industries. In order for thermal plasma spraying of silicon to continue to have an industrial impact in these industries, careful investigations into the deposition properties must be undertaken. We used a Thermach gun and powder feeder, to deposit silicon onto 100 mm x 50 mm x 1.6 mm steel samples. Coating cross-sectioning and image analysis was performed in order to evaluate the coating’s microstructure and porosity. Mechanical property measurements consisted of hardness testing on the coating cross sections. In addition, scanning electron microscopy and optical microscopy were conducted. These results combined for an analysis into the deposition properties of silicon coatings using various particle sizings, plasma power, and spray distances. Correlations between these input parameters and their effect on the microstructure are critical to semiconductor depositions of silicon.
Plasma Sprayed and Electrospark Deposited Zirconium Metal Diffusion Barrier Coatings
Authors: Hollis K.J. , Pena M.I.
Published: September 2022

Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.
Study on Microstructure and Electrochemical Performance of Ni/YSZ Anode Deposited by APS
Authors: Li C.-X. , Li R.-T. , Yang G.-J , Li C.-J
Published: September 2022

Atmospheric plasma spraying (APS) is one of the most promising methods for manufacturing the components employed in solid oxide fuel cells (SOFCs) due to its fast deposition rate and cost-effective characteristics. The anode activity can be improved through increasing the triple-phase boundaries (TPBs) at the electrolyte/anode interface. The active TPBs length, and consequently the performance of the cell, can be enhanced by varying the compositions and microstructure of the APS anode. In this paper, agglomerated powders of NiO and YSZ are prepared by a spray-drying method for preparation of SOFCs anode. The anode was deposited using NiO/YSZ composite powder by APS at different plasma arc power. The influences of plasma arc power on the microstructure and electrochemical performance of Ni/YSZ anode are investigated for the optimization of SOFCs anode.
Relationships Between Process Parameters, Microstructure and Adhesion Strength of HVOF Sprayed IN718 Coatings
Authors: Lyphout C. , Nylén P. , Östergren L.
Published: September 2022

Fundamental understanding of relationships between process parameters, particle in-flight characteristics and adhesion strength of HVOF sprayed coatings is important to achieve the high coating adhesion that is needed in aeronautic repair applications. In this study statistical Design of Experiments (DoE) was utilized to identify the most important process parameters that influence adhesion strength of IN718 coatings sprayed on IN718 substrates. Special attention was given to the parameters combustion ratio, total gas mass flow, spray distance and external cooling, since these parameters were assumed to have a significant influence on particle temperature and velocity. Relationships between these parameters and coating microstructure were evaluated to fundamentally understand the relationships between process parameters and adhesion strength.
Effect of Surface Morphology of MCrAlY Bond Coats on the Isothermal Oxidation Behavior
Authors: Li Y. , Li C.-J. , Zhang Q. , Xing L.-K. , Yang G.-J.
Published: September 2022

Surface morphology of MCrAlY bond coats is one of the factors that affect the oxidation behavior and the thermal stability of thermal barrier coatings. In the present study, the isothermal oxidation behavior of cold sprayed MCrAlY bond coat was investigated at three surface conditions: as-sprayed, polished and shot-peened conditions. The MCrAlY bond coat with sputters adhered weakly on the surface prepared by low-pressure plasma spraying was also employed. The above four types of surface conditions were employed to investigate the effect of the surface morphologies of MCrAlY (M=NiCo, Ni) bond coats on their oxidation behavior. MCrAlYs with the compositions of Ni20Cr10AlY and Ni23Co20Cr8.5Al5.0Ta0.6Y were employed for bond coat deposition. Cold-sprayed Ni20Cr10AlY exhibited a higher oxidation rate than that of the cold-sprayed Ni23Co20Cr8.5Al5.0Ta0.6Y bond coats. After 10 hrs oxidation, the TGO on the as-cold-sprayed bond coat surface was merely constituted by Al2O3, while the TGO on the bond coat surface attached with sputters was composed of Al2O3 and spinel. After 500 hrs oxidation, Cr2O3 and porous spinel appeared in the TGO on the two surfaces of as-cold-sprayed bond coat. The growth of Ni/Cr-oxides was attributed to the Al depletion. The content of spinel on cold-sprayed NiCrAlY decreased after shot-peening.
Loading Effect in Plasma Spraying: from In-Flight Particle State Distributions to Diagnostic Reliability
Authors: Shinoda K. , Tan Y. , Sampath S.
Published: September 2022

The effects of powder loading on temperature distributions of yttria-stabilized zirconia particles during flight, which can be used as a melting status indicator, were investigated in atmospheric dc plasma spraying. Commercially available diagnostic systems were utilized to measure the state of in-flight particle parameters. As the powder feed rate was increased, the intensity of a peak related to the latent heat increased, suggesting the increase of semi molten particles. Interesting findings are that the deposition efficiency of the coating actually increased in some conditions at higher powder feed rates. This implies that higher molten degrees of particles do not always give higher deposition efficiencies. The loading effects also affected the result of diagnostics, which requires special care when the diagnostic condition is different from the actual spray conditions.
The Improvements of Thermal Spray Toolkit, Extended Software for Robotic Off-Line Programming
Authors: Fang D. , Deng S. , Liao H. , Coddet C.
Published: September 2022

Thermal Spray Toolkit (TST) is an extended program (Add-in) of RobotStudio which is off-line programming software of ABB Company. The Thermal Spay Toolkit can generate the robot trajectories rapidly, accurately and automatically for most workpieces with a simple and regular form. In recent years, the growing demand for spraying workpiece of various shapes provides a strong motivation to develop new functions to Thermal Spray Toolkit. This paper describes the development of thermal spray toolkit and presents new functions: robotic trajectory auto-generation for complicated surfaces and the optimization of trajectory. Furthermore, many simulations are implemented to optimize trajectory in RobotStudio. Compared to the former thermal spraying without applying this toolkit, the coating quality is improved greatly. These results demonstrate that the new functions are reliable and efficient.
Improved Mechanical Properties of Coatings and Bulk Components as a Function of Grain Size
Authors: Melnyk C. , Schroeder S. , Grant D. , Gansert R. , Watson M.
Published: September 2022

Thermal sprayed coatings produced from ultrafine- and nano- and near-nano grained powders of tungsten carbide- 10 wt.% cobalt-4 wt.% chromium (WC-10Co-4Cr) are reported to provide improved properties as compared to conventional powders. These materials show great potential for applications in the aerospace, oil & gas, power, and many other industries. A study is proposed to investigate the influence of WC grain size on HVOF coating properties. Thermal spray coatings will be produced from powders consisting of grains of WC from micron- to near-nano in size in a Co-Cr matrix. The Hall-Petch relationship cites the strengthening of materials by reducing the average crystallite (grain) size. An examination of consolidated forms will be performed using the same powders used in thermal spray in the spark plasma sintering (SPS) consolidation. The mechanical properties of thermal spray coatings have been reported to relate to those of bulk materials. Improvements observed in the HVOF spray coatings will be compared to those of bulk samples.
Effect of Stand-Off Distance on EMAA Splats Deposited onto Glass and Mild Steel Substrates
Authors: Xie W. , Saber-Samandari S. , Morks M. F. , Alamara K. , Wang J. , Berndt C.
Published: September 2022

Thermal spray coatings are comprised of millions of heated particles that are driven at high velocity to impact against a substrate; thereby building up to form a consolidated coating. Thus, investigating single solidified droplets contributes to fundamental understanding of coating evolution and their properties. In this study, Scanning Electron Microscopy (SEM) studied the splat morphology of flame sprayed ethylene methacrylic acid (EMAA) with respect to the stand-off distance when deposited onto glass and mild steel substrates. A splat shape transition from a “splash” to a “disc shape” was observed. The morphology of EMAA droplets can be described as a ‘splash splat’ when sprayed onto mild steel at room temperature, whereas a 35 cm stand-off distance produced a disk-shaped splat when the polymer was deposited onto a glass substrate.
Effect of The Ceramic Component on Cold Sprayed Metal Ceramic Coatings
Authors: Sova A. , Kosarev V. , Papyrin A. , Smurov I.
Published: September 2022

Spraying metal-ceramic coatings is a complicated task because, in addition to the spray parameters of the metal particles, it is necessary to take into account those of ceramics. This paper presents some results concerning the effect of the nature, particle size, and velocity of ceramics on the metal-ceramic coating properties. Copper and aluminium powders are used as metal components. Two fractions (fine and coarse) of aluminium oxide and silicon carbide are sprayed in the tests. Ceramic particle velocity is varied by the particle injection into different zones of the gas flow: in the subsonic (pre-chamber) and supersonic parts of the nozzle, and in the free jet after the nozzle exit. Simulation results and measurements of the particle velocity by the track method are compared. Influence of the ceramic particle parameters on the coating formation process and its properties is discussed.
Near-Net-Shape HVOF Coating and Finishing Techniques for Highly Stressed Components in Aircraft Industry
Authors: Matthäus G. , Wolf J. , Ackermann D.
Published: September 2022

Applications such as landing gears and turbine blades place new demands on near-net coating technologies. Such demands include the replacement of traditional grinding, finishing and grit basting techniques with better, more efficient methods. A method is described for near-net-shape spraying of complex internal and external geometries which eliminates the need for grinding. This is achieved by combining automatic, mass-flow controlled HVOF grit blasting with Nano-HVOF methods. The resulting coating displays an as-sprayed surface roughness of less than 2 μm Ra and a tight control over coating thickness and distribution. By carefully controlling the coating thickness and surface properties, it is possible to hone the required dimension and surface roughness.
Observation of Microstructures in Thermal Sprayed Coatings and Single Deposited Splats using Ion Beam Milling
Authors: Kim K. H. , Watanabe M. , Kuroda S. , Kawano N.
Published: September 2022

In this study, we investigated microstructures of thermal sprayed coatings and single deposited splats using two types of ion beam milling: one is argon ion beam for the cross-sectioning of thermal sprayed coatings in a cross section polisher, the other is gallium focused ion beam for the cross-sectioning and TEM sample preparation of single deposited splats. The cross section of WC-Co coatings fabricated by the polisher showed that it created a mirrored surface with minimizing artifacts such as pull-outs of ceramic particles or smearing of pores during conventional metallographic preparations. A thin and locally re-thinned membrane of single warm-sprayed nickel splat was feasible to observe the internal interface of particle/substrate in high resolution electron images. The substrate was heavily deformed by the impact of nickel particle with high kinetic and thermal energies. The particle and the substrate were intimately bonded without any voids or gaps.
Metastable Austenite Type Core Wire for Arc Spraying – Modeling of Heat Transfer in End Face and Coating Structure Analysis
Authors: Korobov Yu. , Filippov M. , Belozertsev A. , Neveszin S. , Shymiakov V.
Published: September 2022

Analysis of melting mode of core wire at Arc Spraying helped to explain a possibility of incomplete fusion of a charge of a core wire. Influence of physicochemical parameters of feedstock and atomization modes was established. Analysis results helped to develop a metastable austenite type Core Wire for Arc Spraying of good wear resistance. Applications results are shown.
Predicting the Thermal Conductivity of AlSi/Polyester Abradable Coatings: Effects of the Numerical Method
Authors: Bolot R. , Seichepine J. L. , Qiao J. H. , Coddet C.
Published: September 2022

The final target of this study was to achieve a better understanding of the behaviour of thermally sprayed abradable seals such as AlSi/polyester composites. These coatings are used as seals between the static and rotating parts in gas turbine applications. The machinability of the composite coatings during the friction of the blades depends on their mechanical and thermal effective properties. In order to predict these properties from micrographs, numerical studies were performed with different software packages such as OOF developed by NIST and TS2C developed at the UTBM. In 2008, differences were reported concerning prediction of effective thermal conductivity obtained with the two codes. In the present paper, it is shown that a particular attention must be paid to the mathematical formulation of the problem. In particular, results obtained with a finite difference method using a cell centre approach or a nodal formulation, allow explaining the discrepancies previously noticed. A comparison of the predictions of computed effective thermal conductivities is thus proposed for different codes and different meshing methods. This study is part of the NEWAC project, funded by the European Commission within the 6th RTD Framework program (FP6).
In Situ Observation of Impact Phenomena of Zirconia Molten Drops in Millimeter Scale Via Aerodynamic Levitator
Authors: Shinoda K. , Nagashio K. , Murakami H. , Kuroda S. , Kuribayashi K.
Published: September 2022

Spreading and rapid solidification behavior of millimeter-scale molten drops of 8 wt.% yttria-stabilized zirconia (YSZ) has been experimentally studied utilizing a novel splittable aerodynamic levitator (ADL). The focus was especially on the effect of initial undercooling on the splat formation. An YSZ sphere approximately 2.3 mm in diameter was levitated in a splittable ADL nozzle and melted by a carbon dioxide laser. The molten drop was dropped by splitting the ADL nozzle and impacted on a substrate 15 cm below at a speed of 1.7 m/s. The spreading and solidification behavior of the impacting drop was observed with a high-speed digital video camera. The undercooling of YSZ drops reached to more than 500 K at a containerless state, and the solidification rate was on the order of 1 m/s at this state. When drops were dropped at superheated states, the drop solidified after flattening completed. Meanwhile, when impacted at large undercooling, the drop spreading was suppressed by the solidification. Drastic difference was observed when a drop was impacted on a substrate covered with acetone liquid. The drop was splashing, recoiling, and rebounding despite fact that splashing would not occur at this impact condition.
Phase Composition and Microstructural Responses of Crystalline Mullite/YSZ Coating Under Water Vapor Environments
Authors: Garcia E. , Mesquita-Guimarães J. , Miranz P. , Osendi M. I. , Cojocaru C. V. , Wang Y. , Moreau C. , Lima R. S.
Published: September 2022

Mullite and mullite/ZrO2 bi-layer systems are being considered as environment barrier coatings (EBCs) for protection of Si-based (Si3N4, SiC) substrates against water vapor corrosion for application in forthcoming turbine engines. An approach to reduce the thermal expansion mismatch between mullite and ZrO2 layers in those coatings would be to tailor intermediate mullite/Y-ZrO2 composite layers. The feasibility of these composite layers is studied in a comparative manner by plasma spraying both single mullite and bi-layer coatings of mullite and of mullite/ Y-ZrO2 (75/25 vol %.) over Hexoloy SiC substrates. All feedstock materials are equally prepared using spray drying methods as the mix powders are not commercially available. Singular spraying conditions are used to assure enhanced crystallization of the mullite phase. Coatings are aged for 100 h at 1300 °C in a controlled water vapor environment. The effect of water corrosion on the exposed coatings is comparatively investigated, determining changes in crystalline phase by X-ray diffraction (XRD), the crystallization of amorphous phases is highlighted by the use of differential thermal analysis (DTA) tools and the microstructure of the polished coatings is analyzed by scanning electron microscopy (SEM).
Corrosion of Ti Coating Prepared by Modified HVOF Process
Authors: Deng C. M. , Deng C. G. , Liu M. , Huang J. , Zhou K. S. , Chen Z. K. , Wank A. , Schwenk A.
Published: September 2022

Titanium exhibits very good corrosion resistance property because of the formation of very dense oxide coating. Especially the good corrosion against Cl- solution for titanium material makes it wide applications in sea industry. It is very difficult to deposit titanium coating under atmospheric condition due to the strong affinity with oxygen and nitrogen especially in high temperature plume. Except the expensive LPPS process, much attention has been paid to the newly developed cold spraying. Unfortunately the stringent requirement for the starting power and low production efficiency limit the application of the cold spraying. A modified HVOF process was developed by reducing the outlet diameter of chamber and by directly introducing water into chamber, therefore lower plume temperature and higher chamber pressure than conventional HVOF process can be achieved. Attempts to deposit Titanium coating were carried out, and immersion of Titanium coated A3 steel into artificial seawater was performed in order to evaluate the density of as-sprayed Titanium coating. The results showed that dense Titanium coating could be obtained after parameter optimization and very few corrosion spot was observed on the surface of Titanium coated A3 steel after immersion into artificial seawater for 120 h.
Experimental Investigation of Fretting Wear on Nitrided and Thermal Spray Coated Ti-6-4 Parts for Lift Fan Applications
Authors: Patil P. , Sadeghi F. , Dixit S. , Dixit R. , Chin M.
Published: September 2022

The fretting phenomenon was investigated experimentally in contacts between nitrided, coated and nitrided-coated Ti-6-4 rods against uncoated M50 rods generating a circular Hertzian contact. A fretting wear test rig was designed and developed to facilitate mounting of rod specimens of different coating thicknesses. Fretting wear tests were performed on low temperature and high temperature nitrided Ti-6-4 rods as well as on T-800 (CoCrMoSi) thermal spray coated Ti-6-4 and T-800 coated M50 rods. Finally, tests were carried out on Ti-6-4 rods nitrided at low and high temperatures and T-800 thermal spray coated on the top. The results obtained from fretting tests of each surface against uncoated M50 are studied and compared. Fretting wear volumes and surface profiles are presented for the contacts studied. The fretting wear resistance of each surface is quantified and compared with Archard’s wear equation. The role of amplitude of motion and number of cycles on the fretting wear of coatings is discussed. It was observed that increase in fretting wear resistance of uncoated Ti-6-4 rods by nitriding is greater than thermal spray coating. The fretting wear resistance was found to be higher for high temperature nitrided-coated rods than for low temperature nitrided-coated rods.
Thermal Cycle Resistance of Oxidation-Resistant Metallic Coatings
Authors: Takahashi S. , Hatano M. , Kojima Y. , Harada Y. , Kawasaki A. , Ono F.
Published: September 2022

Thermal cycle resistance of Ni-20Cr, Ni-50Cr and CoNiCrAlY coatings manufactured by air plasma spraying was investigated according to a Japanese Industrial Standard "Testing method for thermal cycle resistance of oxidation resistant metallic coatings (JIS H 8452)” established in 2008. The specimens were exposed at 1000 °C and 1093 °C in air under cyclic heating and cooling condition up to 100 times. The thermal cycle resistance of oxidation-resistant metallic coatings was found to depend strongly on the testing temperature and the chemical composition of the coating materials. In the thermal cycle test at 1000 °C, the remarkable failure was not observed in any specimen. However, in the thermal cycle test at 1093 °C, although the Ni-20Cr coating caused the spalling on the whole surface of coating, the Ni-50Cr and the CoNiCrAlY coatings exhibited the excellent thermal cycle resistance even after applying the thermal cycles of 100 times, The CoNiCrAlY coating showed the mass gain with increasing the numbers of thermal cycle due to the preferential oxidation between the splats of the thermal spray particles. Furthermore, the failure behavior of specimens was investigated in detail by SEM, XRD and EPMA etc.
Research of Plasma Spraying Process of Nanostructured Zirconia Thermal Barrier Coating
Authors: Sun H. , Wang C. , Liu X. , Qu Z. , Bi J.
Published: September 2022

In this paper, the nanostructured zirconia thermal barrier coatings were prepared on GH3030 high temperature alloy surface by plasma spraying process. The nanostructured agglomerated ZrO2 feedstock was used as initial powders, and the NiCoCrAlY alloy as bond coating material. The relationship between bonding strength and spray current, secondary gas flow and spray distance were analyzed. The optimum parameters were acquired by orthogonal experimental design methods. The microstructures and phase structures of nanostructured zirconia thermal barrier coating were investigated thoroughly by SEM, TEM and X-Ray.
Effect of Temperature on Wear Characteristic of Cast Iron
Authors: Shaha S. K. , Haque M. M. , Dyuti S.
Published: September 2022

Conventional Fe-C-Si alloy cast iron shows good properties at low temperature but at high temperature its properties decrease very sharply. So, to protect this behaviour of cast iron, Si was replaced by Al, since both elements have similar graphitizing effect. In the present study, two types of cast iron, Fe-C-Si and Fe-C-Al, were cast in cold set resin bonded sand mould. After casting, the microstructures were studied using standard metallographic techniques. The wear tests were conducted using “CSM High Temperature Tribometer” following pin-on-disk method at 25 °C, 100 °C, 200 °C and 300 °C. The worn tracks were characterized using optical profilometer, SEM etc.. The results show that abrasive type wear was observed in both types of cast iron and always the Fe-C-Al cast has low wear rate compared to Fe-C-Si. However, after at 100 °C temperature, the wear resistance of Fe-C-Si cast iron starts to decrease whereas at lower temperature, it remains almost unchanged. The wear rates for Fe-C-Si alloy cast iron are 12.42, 16.51, 46.75 and 98.87x10-5mm3/N/m whereas the wear rates for Fe-C-Al cast iron are 3.32, 4.23, 4.40 and 8.15x10-5mm3/N/m at 25 °C, 100 °C, 200 °C and 300 °C, respectively.
Comparative Analysis of Anti-Cavitation and Abrasion Resistance Properties of two Different Detonation Coatings
Authors: Huang K.-F , Fang J.-P. , Wu S.-H. , Xu B. , Ye L. , Liu Z.-K.
Published: September 2022

Combined damage of cavitation and abrasion is one of the serious problems that affect lifetime and performance on hydraulic machineries and its components. Thermal spraying as a surface hardening and protection technology is required to protect hydraulic components, such as water turbine and radial flow pump, in general. Detonation sprayed coating with high abrasion resistance is one of the promising solutions as the protective coating against combined damage of cavitation and abrasion under solid-liquid double phase liquid conditions. In this study, NiCr-Cr3C2 and WC12Co coatings on the No.45 steel substrate surface have been formed by detonation spraying with the same technological parameter and their properties such as microstructure and microhardness have been studied. The cavitation and abrasion behavior of coatings and the substrate has been investigated using a self-manufactured rotating disk system. The resistance properties of cavitation erosion and abrasion have been illustrated and analyzed with the substrate by the cumulative mass loss curves. The results indicate that, the resistance properties of cavitation erosion and abrasion of NiCr-Cr3C2 coating are the best.
Degradation Mechanisms of Thermally Sprayed Coatings in Chloride Containing Electrolytes
Authors: Laurila J. , Niemi K. , Vuoristo P.
Published: September 2022

Thermally sprayed cermet coatings are widely used in pulp and paper industry and also in other applications of such corrosive conditions where chlorine is present. In these conditions corrosion resistance and wear resistance of the coatings are the most important characteristics. Corrosion resistance can be improved by sealing the corrosion sensitive base material surface under the coating from chlorine containing environment. Test materials in this work were thermally sprayed WC-10Co4Cr, Cr3C2-25NiCr and Sanicro 28 coatings prepared using HVAF and arc spray techniques. The degradation of the coatings and base material surface was characterized using micro hardness tests, optical and scanning electron microscopy, and also by conventional weight loss measurements. Wear resistance of the coatings was evaluated using modified rubber-wheel abrasion tests. In this work ASTM G48 corrosion testing standard was utilized in corrosion testing of these corrosion resistant thermally sprayed coatings. In demanding chlorine containing corrosion conditions it is essential to understand where the corrosion is concentrating in the structure. In the studied corrosion conditions Sanicro 28 and Cr3C2-25NiCr coatings were heavily corroded inside the coating material. Corrosion resistant Cr3C2-25NiCr cermet coating was corroded also between the coating and the base material and the adhesion between the base and the coating was lost in some of the specimens after one day exposure. Unexpectedly HVAF sprayed WC-10Co4Cr coating was giving the best performance of the coatings tested in this work.
Oxide Ion Conductivity in Dense Apatite-Type Lanthanum Silicate
Authors: Gao W. , Liao H.-L. , Coddet C.
Published: September 2022

In order to improve the ionic conductivity of lanthanum silicates, which have been considered as the new electrolyte candidates for intermediate temperature solid oxide fuel cells (IT-SOFCs), the feedstock powders are prepared by sintering the mixed oxide powders in different temperatures and sintering times. The main phase of all the samples is the hexagonal apatite structure. The apatite-type ceramic coatings with a typical composition of La10(SiO4)6O3 are deposited by atmospheric plasma spraying (APS). The influence of sintering time of feedstock powders on the electrical properties of La10(SiO4)6O3 electrolyte coatings is reported here. The highest conductivity of the dense composite electrolyte coatings reaches 6.8×10-6 S·cm-1 at 435 °C in air which is comparable to other apatite-type lanthanum silicate (ATLS) conductors.
The PROTAL Process Applied on Cold Spraying to Improve Interface Adherence and Coating Cohesion—Case of Titanium and Nickel Based Alloys
Authors: Costil S. , Irissou E. , Danlos Y. , Legoux J.-G. , Wong W. , Yue S. , Moreau C. , Coddet C.
Published: September 2022

Cold spraying is particularly suitable for elaborating heat and oxidation sensitive coatings. Due to the fact that the particles are not melted during the spraying process, it is thus possible to elaborate coatings without chemical modifications. Nevertheless, according to the materials considered, some interface defects can be detected inducing an inadequate adhesion between the substrate and the coating. Bonding mechanisms are not only strongly dependent on the particle velocity but also on the state of the surfaces. By this way, surface pre-treatments can be necessary to improve adhesion. From all the surface modification technologies, laser ablation process is very interesting due to its flexibility by using optical fibers and due to the perfect control over the treated area. It is then possible to interact with the material during all the spraying process on the substrate surface as well as on the interface layers. This is particularly the aim of this study which consists in exploring the laser influence, implementing the PROTAL process, on the different interfaces quality for coatings elaborated by cold spray on metallic substrates. By controlling the chemical composition of the materials, the coating cohesion as well as the adhesion level, coatings were sprayed on pure titanium and titanium and nickel based alloy substrates.
Influence of Improved Plasma Gun on the Particle In-Flight Properties of Temperature and Velocity
Authors: Yang H. , Li G. , Wang L.
Published: September 2022

The influence of spray parameters on particle with the improved plasma gun was studied by using SpryWatch-2i System. The results show that the particle velocity increases and exceeds the velocity of sound when using a new designed nozzle (C2 nozzle) during the plasma spraying. Under a certain condition, the particle velocity varies as the spray distance rise firstly, decline then, as the primary gas pressure increases, the particle velocity increases, the particle temperature drops firstly then increase, the velocity increase a little. But as the steadily increase of the flow rate, the influence on the particle temperature drops, the influence of arc voltage on particle velocity and temperature is slightly. Arc current influent little on particle temperature, but the particle velocity increase in a range.
Effects of Radial Liquid Injection on Atmospheric Plasma Characteristics
Authors: Soysal D. , Kavka T. , Ansar A.
Published: September 2022

Impact of liquid injection on atmospheric plasma has been measured by an enthalpy probe and visualized by shadowgraphy. Liquid was injected by two nozzles. A solid stream nozzle with 0.3 mm diameter and an atomizing nozzle with a spray angle of 30°. For constant liquid flow rate and varied plasma current an optimal injection parameter has been obtained. Influence of different flow rates on plasma characteristics has been examined. Full profiles along each axis show differences for different injection techniques in enthalpy, temperature, velocity and composition.
Characterization of Some Electric Arc Sprayed Cored-Wire and Nano Cored-Wire Cermet Coatings
Authors: Tuiprae M. , Wirojanupatump S. , Jiansirisomboon S.
Published: September 2022

Microstructures and properties of electrical arc sprayed cored-wired coatings were investigated and compared in this work. Three types of cored-wired studied were WC-Ni, WC-Fe and nano WC-Fe The as-received cored-wire were characterized prior to be sprayed. In-flight particles were collected during spraying in order to reveal particle morphology and size distribution forming splats. Size distribution analysis of the filler particles showed that nanostructured WC-Fe had a comparable mean filler particle size with that of the WC-Fe and were larger than that of the WC-Ni. The difference in filler particle size of starting cored-wire was well correlated with the in-flight particle size produced. Nano WC-Fe cored wire coating had the lowest porosity and roughness compared to others with a comparable hardness to WC-Ni cored wire coating with rather different coating microstructures.
Addition of hBN to NiAl Coatings Deposited using APS and HVOF Thermal Spraying
Authors: Hsiao W.T. , Su C.Y. , Huang T.S. , Liao W.H. , Leu M.S.
Published: September 2022

High velocity oxyfuel (HVOF) thermal spraying and atmosphere plasma spraying (APS) were using to deposit a nickel aluminum (NiAl)/ hexagonal boron nitride (hBN) composite coating. The hBN powder was added to the Ni-5Al coatings to increase the lubrication property of the coatings. The hBN material was added to the NiAl alloy powder after either blending or ball milling to create the NiAl/hBN composite powders. The NiAl/hBN composite powders were than deposited as NiAl/hBN composite coatings. The velocity and temperature of the in-flight particles during thermal spraying were monitored using a DPV 2000 instrument. The morphology, microstructure and composition of the coatings and powders were analyzed. The coatings with the best lubrication and most uniformly deposited microstructure were formed when the NiAl/hBN coatings were deposited using the atmosphere plasma spraying method.
Plasma Sprayed Electrolyte of Magnesium Doped Lanthanum Silicate with Apatite-Type Structure
Authors: Sun F. , Liao H. , Zhang N. , Rapaud O. , Coddet C.
Published: September 2022

Magnesium doped lanthanum silicate with apatite-type structure was prepared by solid state sintering, as a solid electrolyte for intermediate-temperature solid oxide fuel cells. The electrolyte layers were fabricated by APS, followed by post heat treatments, and their structures and phase were characterized by SEM and XRD. It is showed that an amount of amorphous oxides exist in as-sprayed electrolyte layer, and then disappear after a post heat treatment in air furnace at temperature up to 1000°C. The gas permeation of electrolyte layers was measured by a specific instrument with pure H2 and O2 at room temperature. The conductivity of plasma sprayed electrolytes was studied by impendence spectroscopy in the range of 500-900°C in air.
Preparation of Nanocomposite GDC/LSCF Cathode Material for IT-SOFC by RF Induction Plasma Spraying
Authors: Shen Y. , Gitzhofer F. , Almeida V.
Published: September 2022

Homogenous mixtures of Ce0.8Gd0.2O1.9 (GDC) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF6428) nanopowders were successfully synthesized using radio frequency (RF) induction plasma by axial injection of a solution. Two kinds of powders with different mass ratio of GDC/LSCF, such as 3/7 and 6/4, were obtained. The crystallinity and morphological features of the powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The particles are almost globular in shape with a diameter lower than 100nm and the BET specific areas around 20m2/g. In addition, suspensions, made with the composite nanopowders and ethanol, were used to deposit some cathode coatings using suspension plasma spray method. Several initial results of the coatings are also presented. The coatings are homogeneous and porous with cauliflower structures.
Microstructure and Electrochemical Behavior of Sm0.5Sr0.5CoO3 Deposited by Solution Precursor Plasma Spraying
Authors: Wang X.-M. , Li C.-X. , Li C.-J. , Tian L.-H. , Song B. , Yang G.-J.
Published: September 2022

Solution precursor plasma spraying (SPPS) was employed to prepare porous Sm0.5Sr0.5CoO3 (SSC) cathode for solid oxide fuel cell (SOFC). The surface and cross-sectional morphology of the SSC deposit were characterized by scanning electron microscopy. The effect of annealing on SSPS SSC microstructure was examined. The electrochemical behavior was investigated through the impedance spectroscopy. The results showed that the SPPS SSC cathode deposited at a spray distance of 80 mm exhibits multidimensional porous microstructure. The porous film of the partially crystalline perovskite phase with a fine microstructure was obtained after annealing at 900 °C for 2 hours in air. The electrochemical measurement showed that the specific surface resistance of SSC decreased significantly with the increase of test temperature and yielded a specific surface resistance of 2.6 Ω·cm2 at 800°C.
Effect of Carbide Type on the Properties of Low Vacuum Plasma Sprayed W-Based Composite Coating Layer
Authors: Lee K.-A. , Jin Y.-M. , Ahn J.-H.
Published: September 2022

The PAS method was used to produce W-ZrC and W-HfC composite powder, and the LVPS process technologies were used to create W composite coating layers. In addition, the mechanical properties, high-temperature resistance, and ablation characteristics of the W composite coatings were compared and analyzed for different types of carbides. For comparison and analysis, Vickers hardness, porosity, and adhesive strength were measured, and plasma torch tests were conducted. The use of the LVPS technologies led to successful production of W composite coatings (W-HfC; W-ZrC), approximately 1,000 μm or above in thickness. ZrC particles were observed in the layers of W-ZrC coating. The porosity was 3.59 % in W-HfC and 7.74 % in W-ZrC, indicating the W-HfC coating had a better pore quality than W-ZrC. Vickers hardness was approximately 120Hv higher in W-ZrC than in W-HfC due to the presence of ZrC particles in the W-ZrC coating. Adhesive strength was found to be nearly identical in both coatings. Results of the evaluation of high thermal resistance characteristics of the W composite coating materials showed that W-ZrC coating performed better in resisting high thermal conditions than W-HfC coating, due to the strengthening effects of ZrC particles in the layers and the generation of ZrO2 phase with high levels of stability in high temperatures.
Lipoleiomioma uterino
Authors: Reyna-Villasmil Eduardo , Rondon-Tapia Martha , Torres-Cepeda Duly
Published: September 2022

El lipoleiomioma es una neoplasia uterina benigna poco frecuente cuya incidencia varía entre 0,03% y 0,2%. Este tumor es considerado una variante benigna de los leiomiomas uterinos típicos. Está formado por una proporción variable de adipocitos maduros y células musculares lisas. La etiología puede estar relacionada con la deficiencia de estrógenos que se produce después de la transición menopáusica; generalmente aparece en mujeres obesas perimenopáusicas o menopáusicas. La sintomatología es inespecífica y la mayoría es diagnosticada de forma incidental. Se presenta un caso de lipoleiomioma uterino en paciente de 45 años quien consultó por presentar dolor abdominal. La ecografía mostró tumor en pared anterior de un útero homogéneo y bien definido. Durante la laparotomía se encontró tumor amarillento y de textura blanda. Se realizó histerectomía total más ooforosalpingectomía. El diagnóstico anatomopatológico fue de lipoleiomioma uterino.
Fibroadenoma vulvar: comunicación de un caso
Authors: Romero Rojas Nery
Published: September 2022

El fibroadenoma es una neoplasia benigna usualmente localizada en mama. Su localización vulvar es extremadamente rara, con publicación de pocos casos. Su origen es incierto y muy debatible, en tanto se piensa que puede originarse de un tejido mamario ectópico vulvar o de glándulas anogenitales similares a las de tejido mamario que existen normalmente. Se presenta un caso inusual de fibroadenoma vulvar en una mujer de 29 años que durante dos años evidenció tumoración a nivel de la vulva que le producía dispareunia y sangrado poscoital. A nivel del labio mayor de la vulva se extirpó un tumor bien delimitado de 3 x 2 x 2 cm, blanquecino, de consistencia firme. En la microscopia se observó un fibroadenoma que por inmunohistoquímica mostró positividad para receptores de estrógeno y progesterona.
Giants with feet of clay: the sustainability of the business models in music streaming services
Authors: Arenal Alberto , Armuña Cristina , Ramos Sergio , Feijoo Claudio , Aguado Juan-Miguel
Published: September 2022

This paper examines the sustainability of the recorded music industry from the perspective of music performers. Music streaming platforms, or digital music service providers (DMSPs), have changed the recorded music industry paradigm since the middle of the 2010s. Business models for performers have evolved from royalty agreements based on sales to more complex remuneration systems based on revenues from a combination of (ad-based) free and paid subscriptions. Previous research has mainly focused on the examination of the business models of streaming services from the point of view of the innovation players (digital platforms) and/or the traditional dominant intermediaries (record labels and publishers). However, not all innovation-driven transformations are sustainable. In this paper, we argue that the sustainability of the main business models in the music industry demands the consideration of the performers’ perspective. We combine a qualitative approach with primary and secondary data sources to investigate the sustainability of existing trends of business models and business practices for different categories of performers, including both monetary values and a description of how revenues are shared. We conclude that DMSPs foster an asymmetric value chain in which the creative players barely capture value while technology-based innovations increase the capability of DMSPs to generate and capture value. Finally, we outline some alternative business models looking for the long-term sustainability of the digital music marketplace.