bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Diagnostic History of a New Electromagnetic Powder Deposition System
Authors: Bacon J.L. , Davis D.G. , Sledge R.L. , Uglum J.R. , Zowarka R.C. , Polizzi R.J. 
Published: May 2021

Abstract
This paper describes the diagnostic tools used in the development of a new electromagnetic powder deposition system. The instrumentation, interpretation of data, and subsequent decisions regarding the direction of system development are discussed. Important system parameters, their impact on system performance, and techniques to measure them are presented. The electromagnetic powder deposition system is based on railgun technology developed by the Department of Defense. The system drives an ionized plasma sheet down the length of a railgun, reaching a final plasma velocity of 4 km/sec. The high velocity plasma, in turn, snowplows [1] a shock compressed gas column in front of it. This gas column sweeps through a powder cloud and accelerates it by viscous drag to a final velocity of 2 km/sec. Important system parameters include particle velocity, gas velocity, gas column pressure, and plasma propagation and velocity. Diagnostic tools include pressure transducers, a high speed digital framing camera, fiber optics and magnetic probes.
Ceramic and Metallic Powder Spheroidization Using Induction Plasma Technology
Authors: Dignard N.M. , Boulos M.I. 
Published: May 2021

Abstract
A study is carried out of the spheroidization of ceramic and metallic powders using induction plasma technology. The process is based on the central injection of the powder in the plasma discharge followed by the in-flight cooling and solidification of the molten droplets prior to their collection at the bottom of a stainless-steel water cooled chamber. The degree of spheroidization is evaluated using image analysis. The results are correlated as a function of the powder feed rate, the plasma operating conditions and the thermophysical properties of the powders treated. The model's fit to the obtained experimental data is very good. The results show that the technology can be successfully used for the spheroidization and densification of a wide range of materials.
Plasma Spraying of Silicates
Authors: Chráska P. , Neufuss K. , Kolman B. , Dubsky J. 
Published: May 2021

Abstract
A search for cheap spraying materials offering interesting properties is conducted in connection with utilization of the high throughput water stabilized plasma. In this regard very promising materials are silicates. WSP PAL 160 was used for spraying garnets in their natural form and fused and crushed basalt. Chemical composition of both these materials is based generally on the same components but their contents are different. Paper reports on the spraying parameters used and then describes the structure and phase composition of deposits as well as their selected properties. Garnet of almandine type can be sprayed very well at a wide variety of parameters while pyrope type spraying is more difficult. Very interesting coatings were made of basalt.
Vaporization and Ultra-Fine Particle Generation during the Plasma Spraying Process
Authors: Gross K.A. , Fauchais P. , Vardelle M. , Tikkanen J. , Keskinen J. 
Published: May 2021

Abstract
The thermal spray process melts powder at very high temperatures and propels the molten material to the substrate to produce a coherent deposit. This heating produces a certain amount of vaporization of the feedstock. Upon exiting the plasma plume the fast cooling conditions lead to condensation of the vapor. An electrical low pressure impactor was used to monitor the concentration of ultra-fine particles at various radial and axial distances. Metal, namely iron powder, showed very high concentration levels which increase with distance. Ultra-fine particles from ZrO2-8Y2O3 reached a peak concentration at 6 cm. Use of an air barrier during spraying decreases the population of ultra-fine particles facilitating the production of a stronger coating.
Plasma Processing of Functionally Graded Materials Part I: Process Diagnostics
Authors: Smith W.C. , Jewett T.J. , Sampath S. , Swank W.D. , Fincke J.R. 
Published: May 2021

Abstract
An investigation into the dependency of the formation of functionally graded materials (FGMs) on process variables was carried out. The initial stage of the investigation involved a complete analysis of the plasma spray parameters used in the fabrication of an FGM constructed of NiCrAlY and partially stabilized zirconia (PSZ). In flight particle temperature, velocity and trajectory data were gathered for individual powders, as well as mixtures of the particle species, over a range of spray parameters. This data was combined with material specific properties such as flowability, apparent density, particle morphology and size distribution. The end result of the studies allowed for size matching of the particle species so as to ensure both species were molten at the nominal spray distance and possessed coincident impact velocities. Following the initial investigation, two spray conditions were selected for further analysis. Individual layers of specific powder mixture ratios were deposited as well as a complete FGM structure. The resulting structures were then compared based on their deposition efficiencies, porosity levels, compositional homogeneity and microstructures.
Engineering Formulas for Flattening of Composite Powder Particles during Thermal Spraying
Authors: Sobolev V.V. , Guilemany J.M. , Martín A.J. 
Published: May 2021

Abstract
Engineering analytical formulas describing variations of the final values of the splat thickness and radius during flattening of composite particles in thermal spraying are obtained. The effective values of the droplet parameters (impact velocity and viscosity) and the Reynolds number are introduced taking into account a composition of the composite particles. Analytical results obtained agree well with the experimental data available.
Scale-Sensitive Fractal Analysis for Understanding the Influence of Substrate Roughness in Thermal Spraying
Authors: Siegmann S.D. , Brown C.A. 
Published: May 2021

Abstract
It is widely recognized that substrate surface roughness, or topography, plays an important role in droplet-substrate interaction and the adhesion of sprayed coatings. A key difficulty in understanding the role that topography plays during droplet impact, wetting and solidification has been the availability of methods for appropriate characterization of the topography. The complex nature of the substrate topographies cannot be adequately characterized by conventional methods such as Ra. In this work, scale-sensitive fractal analyses are considered for advancing the understanding of roughness of grit blasted surfaces in thermal spray applications. Area-scale analysis is performed on 3D data sets acquired from different grit-blasted substrates. From fractal analysis it is known that the apparent area of a rough surface increases as the scale of observation decreases. The area-scale relations are used to guide experimental design for topographical data acquisition and analysis and to better understand the influence of grit blasting on substrates for thermal spray. The potential of these scale-sensitive analysis techniques to fulfill the above bases for supporting statistical correlations and clear physical interpretations is discussed.
Influence of CaSi2 and Si Additions on Properties of Coatings Produced by Plasma Spraying of Composite Powders
Authors: Borisov Yu. , Borisova A. , Tunik A. , Knyaz M. , Bobrik V. 
Published: May 2021

Abstract
Addition of CaSi2 in steel melt leads to a decrease of oxygen content, an increase of the melt flow capability, an improvement of a metal ductility and weldability. For an estimation of CaSi2 and Si additions effect in conditions of thermal spraying composite powders were produced. A base material of these powders particles is nickel, nichrom and iron. CaSi2 and Si are additional components of the powders (3-12 wt. %). Plasma coatings produced with using of these powders exhibit high density and adhesion. The coatings structure has a high grade of microcrystallinity with a decreasing size of lamels. Oxides content in the coatings decreases with an increasing of CaSi2 and Si content in the composite powders, moreover this effect is more essential in case of CaSi2 addition. Addition of CaSi2 and Si to Ni-base coatings increases a microhardness from 1900-2000 MPa to 2200-2850 MPa. In case of NiCr-base coatings this increasing is from 1800-2100 MPa to 2400-3500 MPa.
Characterization of Cr2O3-TiO2-CaF2 Coatings Using Plasma Spray Process
Authors: Ilyuschenko A.Ph. , Shipica N.I. , Vityaz P.A. , Yerstak A.A. , Beliaev A.Y. 
Published: May 2021

Abstract
This paper presents the results of a study on the wear resistance of plasma spray coatings made from Cr2O3-TiO2-CaF2 powders. The composite powders used were produced by self-propagating high temperature synthesis. They were then applied under various conditions in order to optimize the material system, spray process, and application procedures. Based on the results of microstructural examination and wear testing, the thermally sprayed composite coatings have excellent wear resistance, good adhesion, and are self-lubricating at high temperatures.
Elastic Modulus Measurements in Plasma Sprayed Deposits
Authors: Wallace J.S. , Ilavsky J. 
Published: May 2021

Abstract
A technique has been developed to characterize the elastic modulus of zirconium oxide - 8 % yttrium oxide plasma sprayed deposits. A commercial hardness indenter has been modified to record load - displacement as a spherical ball is elastically loaded onto the surface of the material to be measured. The resulting data are used to calculate the elastic modulus. Since the loads used are in the elastic region, the technique is, in theory, nondestructive. Relatively small areas of the material, approximately 50 μm in diameter, are sampled by the indenter, allowing local mapping of elastic modulus variations throughout the deposit. Using this technique, elastic modulus variations have been measured through the thickness of the deposit. Also, different moduli were measured in the cross-section and through the thickness and these differences are correlated with the microstructure. Finally, significant increases in elastic modulus have been found in samples annealed for 2.5 h at 1100°C. These changes have been correlated with small angle neutron scattering measurements of void surface area.
Influence of WC Particle Size and Matrix Composition on the Behavior of WC-Co-Cr Coatings Sprayed by the HVOF Process
Authors: Berget J. , Bardal E. , Rogne T. 
Published: May 2021

Abstract
WC-Co-Cr powders with different WC particle size have been sprayed by the HVOF process. At constant spraying conditions the powders give coatings of different quality. The deposition efficiency during spraying of powders containing large WC particles was found to be low compared to powders with finer WC grains. In addition the amounts of porosity and cracks were different. The coatings have been characterised by different methods. Erosion and erosion-corrosion tests showed that the WC particle size also influence the wear resistance of the coatings. Small WC particle size was found to be beneficial. Chemical composition of the matrix was also found to be decisive for the coating properties. An increase of the chromium content improved the erosion-corrosion resistance.
Residual Stress Measurement in Plasma Sprayed Coatings by X-Ray Diffraction
Authors: Matejicek J. , Sampath S. , Dubsky J. 
Published: May 2021

Abstract
Processing induced residual stresses play an important role in the performance of thermally sprayed coatings. Their precise determination is a key to influence the coating properties by modification of process variables and to understand the processing-property relationship. Among various methods for residual stress measurement, x-ray diffraction holds a specific position by being nondestructive, phase distinctive, localized and applicable for real parts. The sin2ψ method is commonly applied for bulk materials as well as coatings. However, the results are often reported without sufficient experimental details and the method is used in its simplified form without justification of certain assumptions. In this investigation, the sin2ψ x-ray diffraction method was used to measure residual macrostress in plasma sprayed Ni, NiCrAlY and ZrO2+8%Y2O3 coatings. Reproducibility of the method was tested and the assumptions allowing its use are discussed and experimentally verified. For Ni coatings, a comparison with blind hole and neutron diffraction measurements is presented. The results are discussed with respect to processing, structure and properties of the coatings.
Methods of Determination and Control of Residual Stresses in Plasma Spray Coatings
Authors: Dekhtyar L. , Kleyman A. , Andreychuk V. , Berman S. 
Published: May 2021

Abstract
Residual stresses exert profound influence on the longevity of parts with thermal spray coatings. The distribution and value of the residual stresses depend on method of coating deposition, composition of the applied material, parameters of thermal spraying and methods of post-treatment. Therefore, the study of the influence of the various technological factors on the residual stresses in the plasma spray coatings is very important. Due to heterogeneity of the coating, residual stresses can be determined only by the experimentation by using new methods which take into consideration real values of elastic characteristics and density of elementary layers. Methods and formulas for the calculations of the residual stresses in coatings deposited on bars, rings, discs, cylinders are presented. Experimental results for the various thermal spray coatings are also shown. These results can be used for the optimization of coating deposition and would supplement the existing database.
HVOF-Sprayed Alloy In718 – The Influence of Process Parameters on the Microstructure and Mechanical Properties
Authors: Voggenreiter H.F. , Huber H. , Spies H.-J. , Baum H. 
Published: May 2021

Abstract
New near-net-shape structures of alloy Inconel 718 processed by HVOF spraying require optimum mechanical properties. Dominant factors defining the material quality are the particle properties velocity and temperature adjusted by the HVOF process parameters. Based on theoretical analysis of the HVOF process, experiments were performed with a defined variation of primary process parameters, producing coating samples of alloy 718 and measuring the particle velocities. Microstructural and X-ray analysis shows that in coatings with a high fraction of molten phase and high velocity, mainly divalent and spinell-type oxides are formed during particle impact on the substrate. Due to severe oxidation of the y'/y''- forming elements Ti, Al and Nb, precipitation-hardening effects of In 718 coatings are low. This leads to merely mediocre mechanical properties. The reduction of the molten phase to nearly zero leads to a drastic decrease of the oxide formation. The hardening γ'/γ'' phases are precipitated homogeneously in the Ni-base matrix. Strength values comparable to cast and wrought alloy In718 are attained by spraying with a low molten-phase fraction and high particle velocity. However, extensive intergranular 8-phase precipitation due to too high an Nb content of the powder causes only mediocre fracture elongation. Coatings up to 10 mm thick have been sprayed. The construction effort and hence the costs and weight of combustion chambers for hypersonic propulsion systems are to be reduced through direct thermal spraying of the loadbearing metallic pressure jacket onto the tubular cooling system. As a semifinished product, the selected Inconel 718 alloy exhibits good mechanical properties in the cryogenic temperature range as well as under higher thermal loads, and is commercially available in powder form. Aging serves to increase the strength up to the range of 1,200 N/mm2. For the sprayed In718 version, coating thicknesses in the centimeter range, a porosity &lt; 1% and mechanical properties comparable with those of the cast version are required. The objective of the research work is to optimize spray-process control so that the resultant structural thick layers meet the design as well as the material requirements with respect to combustion-chamber technology. This necessitates elaborating the dominant microstructural parameters influencing the mechanical properties and the effect on them of the spraying process, and correlating them with the particle-condition parameters and the process parameters [1].
High Velocity Oxy-Fuel Thermal Sprayed Coatings as Alternates to WC-12Co Coatings and Chromium Plating
Authors: Mutasim Z. , Banker V. , Rimlinger C. 
Published: May 2021

Abstract
Tungsten carbide-12 wt.% cobalt (WC-12Co) coatings and chromium plating are used to provide wear resistant surfaces in gas turbine applications. These treatments provide surfaces with hardnesses greater than 60 Rockwell C. In addition, a surface finish better than 8 microinches RMS is required for optimum performance. To achieve this surface finish, diamond grinding is required. The diamond grinding step adds considerable cost to the product and economical benefits could be achieved if more conventional grinding techniques were incorporated. A program was initiated to develop an alternative thermal spray coating, with a target hardness lower than 60 Rockwell C, but high enough to provide the wear resistance required. Spray development was conducted on five commercially available materials using the Diamond Jet 2600 high velocity oxy-fuel process. Laboratory evaluation included coating microstructure, macro- and microhardness, bond strength, salt spray corrosion, and cyclic compression tests.
WC-Co Detonation Coatings Having a Hybrid Amorphous-Nanocrystalline Structure Display Improved Properties
Authors: Shmyreva T. , Britun V. 
Published: May 2021

Abstract
X ray diffraction and transmission electron microscopy studies and measurements of hardness and void content were carried out for WC-20% Co coatings produced by detonation flame spraying at various oxygen/acetylene ratios in the detonating gas mixture. It was demonstrated that successive transition from (WC+Co) to (W2C+Co3W3C) to (W+CO7W6) occurs as the oxygen content in the mixture is increased, and that amorphous-nanocrystalline structures form in the coating. Two types of these hybrid structures were revealed, one including an amorphous metallic matrix containing precipitates of intermetallic nanocrystals, the other having an amorphous oxide matrix and nanocrystalline precipitates of CO3O4 and WO3. The hybrid structures were shown to improve coating density and hardness.
Structure-Property Relationships of TiC-Ni+Ti and (Ti,W) C-Ni Powders Manufactured by the SHS Process, and the Resultant HVOF-Sprayed Coatings
Authors: de Paco J.M. , Nutting J. , Guilemany J.M. , Sánchez F.J. , Miguel J.P. , Smith P. 
Published: May 2021

Abstract
The technology of thermal spraying is approaching maturity, and in the quest to reduce production costs whilst maintaining coating quality, attention is turning increasingly to more cost-effective routes for the manufacture of the starting powders. One such route is self-propagating high-temperature synthesis (SHS), which reduces the required energy input for powder production. In this work, TiC-Ti+Ni and (Ti, W)C-Ni powders produced by the SHS process have been studied in the as-received and as-sprayed states, to evaluate the suitability of SHS powders for the production of wear-resistant coatings. The starting powders and the coatings produced by atmospheric-plasma and HVOF spraying have been characterised using analytical (XRD, EDS) and microscopical techniques (optical, SEM). The technological properties of the as-sprayed coatings have also been characterised, including hardness, wear resistance (using a Rubber-Wheel test (ASTM G-65)) and corrosion resistance (in marine water environment).
The Effect of Mounting Technique on the Microstructure of Thermal Barrier Coatings
Authors: Sauer J.P. , Leonhardt T. , Geary A.R. 
Published: May 2021

Abstract
The characterization of a thermal barrier coating (TBC) using routine metallographic methods has had investigators uncertain as to the authenticity of the microstructure concerning porosity, cracking and other features. Mounting is a very important step in the process. A greater understanding of relationships between high and low viscosity mounting epoxies exposed to vacuum impregnation, pressure impregnation procedures (PIP), and the combined methods is the goal of this paper. This study will attempt to show how variations in sample mounting procedures will affect the final results in conjunction with varied metallographic procedures.
The Effects of Manual vs. Semi-Automatic Metallographic Specimen Preparation of Thermally Sprayed Coatings
Authors: Blann G.A. 
Published: May 2021

Abstract
If the microstructure of thermally sprayed coatings is to be accurately evaluated, proper metallographic specimen preparation techniques need to be utilized to reveal the true coating characteristics. Variations of the materials used and the method of application on a substrate requires variations in the metallographic preparation procedure. The ASTM and Best Recommended Practices Committee of TSS are developing metallographic standards for thermally sprayed coatings using semi-automatic or automatic preparation equipment There are laboratories that continue to prepare coating specimens manually due to an inability to upgrade their equipment, and they must meet industry standards of evaluation. The purpose of this paper is to assist these laboratories in manual preparation that will enable them to produce accurate coating characteristics.
Dutch Progressive Jews and Their Unexpected Key Role in Europe
Authors: Brasz Chaya 
Published: May 2021

AbstractLiberal Judaism remained absent in the Netherlands during the nineteenth century but finally became successful in the early 1930s under the influence of the Liberal Jewish Synagogue in London and the establishment of the World Union for Progressive Judaism in 1926. It had a specific Dutch character which was more radical than the German refugees who joined in were used to. The Shoah barely left survivors of the prewar congregations, but Liberal Judaism made a remarkable comeback in the Netherlands and had a key role position for Liberal Judaism on the continent of Europe. In a much smaller Jewish community than the French one, the Dutch Progressive congregations for a considerable period formed the largest Progressive community on the continent, next to France. Even today, while comprising ten congregations, it still has a growing membership.
Progressive Judaism in Austria
Authors: Adunka Evelyn 
Published: May 2021

AbstractThe article describes the historical circumstances and context of the beginnings of Progressive Judaism in Central Europe in the nineteenth century, with the rabbis I.N. Mannheimer and A. Jellinek and the famous cantor Salomon Sulzer in the historic Viennese city temple (which still stands today) as the main protagonists. In the interwar period, the founding of the Verein für fortschrittliches Judentum in Vienna, its president Heinrich Haase (1864–1943) and its dissolution (in 1936) are discussed, and biographies of Liberal rabbis in Vienna and in some parts of the Austrian provinces are presented. After 1945 the focus is on the history of the Liberal Viennese community Or Chadasch, founded in May 1990, which is celebrating twenty-five years in November this year with a Festschrift and a Festakt with a keynote speech by Anat Hoffman.