bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electromagnetic and Mechanical Properties of Silica - Aluminosilicates Plasma Sprayed Composite Coatings
Authors: Cipri F. , Bartuli C. , Valente T. , Casadei F. 
Published: September 2022

Abstract
The physico-chemical and thermo-mechanical properties of aluminosilicate ceramics (high melting point, low thermal expansion coefficient, excellent thermal shock resistance, low density and good corrosion resistance) make this class of materials a good option for high temperature structural applications. Al2O3-SiO2 compounds show an excellent refractory behaviour allowing a wide use as wear resistant thermal barrier coatings, in metallurgical and glass plants and in high temperature heat exchangers. Moreover the low values of thermal expansion coefficient and of complex permittivity allow to extend the use of this ceramic for microelectronic devices, radome for antennas and electromagnetic windows for microwaves and infrared. The present paper presents the results of an extensive experimental activity carried out to produce thick aluminosilicate coatings by plasma spray technique. APS deposition parameters were optimized on the basis of a surface response approach, as specified by design of experiments (DoE) methodologies. Samples were tested for phase composition, total porosity, microstructure, microhardness, deposition efficiency, fracture toughness and modulus of rupture. Finally, coatings were characterized for their particularly interesting electromagnetic properties: complex permittivity was measured at microwave frequency using a network analyzer with wave guide.
Analysis of In-Flight Particle Properties of Ultrafine Powders
Authors: Bobzin K. , Ernst F. , Zwick J. , Brühl M. , Matthäus G. 
Published: September 2022

Abstract
Demands on functional coatings with high dimensional accuracy and high surface quality has led to increasing interest in processing of very fine powder grades in a particle size range &lt; 25 µm. Fine powders are not only showing a distinct potential for application of thin and dimensionally accurate coatings, but are also very promising for the production of dense and homogeneous coatings with improved mechanical properties. The large specific surface of fine powders is allowing for relatively low thermal energy levels that are introduced into the process. Nevertheless this also requires a very sensitive temperature control, to prevent overheating of the particles. The reduction of the thermal energy level is resulting in significant advantages particularly for the usability of the HVOF process for coating of inner diameters. Within this work in-flight particle properties of ultrafine carbide powders were analyzed. The studied HVOF process allows the adjustment of a broad parameter range by utilization of a hydrogen stabilized liquid fuel combustion process. A conventional straight nozzle type as well as a curved nozzle for internal spraying was studied. For a further assessment of the potential of ultrafine carbide powders also spray trials with a plasma spraying system have been made.
Repeatability of Measuring Method for HVOF Application
Authors: Malavolta C. , Liao H. , Zhang Ga , Coddet C. , Keller S. , Hansz B. 
Published: September 2022

Abstract
A statistical study of the Spraying Xplorer AMT system was undertaken in order to check that if it can be used as a means of assistance for on-line production control. A patented procedure of the system calibration is explained and some results are presented.
Microstructure Characterization and Property of Plasma Sprayed Nanostructured TBCs
Authors: Li Q. , Li S. , Yang W. 
Published: September 2022

Abstract
The technology and thermal shock properties and thermal conductivity of plasma sprayed nanostructured yttria-stabilized zirconia thermal barrier coatings (TBCs) are studied in this paper. The TBCs on the substrate of Ni3Al based alloy IC-10 were fabricated by using the nanostructured yttria-stabilized zirconia powder under certain plasma spraying conditions. By manipulating the plasma spray process, nanostructured TBCs were obtained. The specimens were thermally shocked from 1000°C, 1100 °C and 1200°C into 20°C water and the morphology and microstructure of the TBCs were evaluated by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal diffusivity was tested by a laser pulse method. The results showed that the nanostructured TBCs had more than 30% reduction in thermal conductivity and the thermal shock lifetimes were much longer than that of the conventional TBCs.
Mechanical and Thermal Transport Properties of Suspension Thermal Sprayed Alumina-Zirconia Composite Coatings
Authors: Oberste Berghaus J. , Legoux J.-G. , Moreau C. , Tarasi F. , Chráska T. 
Published: September 2022

Abstract
Al2O3-ZrO2 composite coatings were deposited by suspension thermal spraying of submicron feedstock powders. The suspensions were injected internally into a Mettech Axial III plasma torch and a Sulzer-Metco DJ-2700 HVOF gun. The different spray processes induced a variety of structures ranging from finely segregated ceramic laminates to alloyed amorphous composites. Mechanisms leading to these structures are related to the feedstock size and in-flight particle states. Compositionally segregated crystalline coatings, obtained by plasma spraying, showed the highest hardness of up to 1150 Hv0.3, as well as the highest abrasion wear resistance (ASTM G65). The HVOF coating exhibited the highest erosion wear resistance (ASTM G75), which was related to the toughening effect of small dispersed zirconia particles in the alumina-zirconia alloyed matrix. The HVOF microstructures also led to low thermal diffusivity, due to high amorphous phase content and limited particle bonding.
HVOF-Sprayed Al2O3-TiO2 Coatings Using Hybrid (Nano+Submicron) Powders: An Enhanced Wear Performance
Authors: Lima R.S. , Moreau C. , Marple B.R. 
Published: September 2022

Abstract
In previous studies, it has been demonstrated that nanostructured Al2O3-13wt%TiO2 coatings deposited via air plasma spray (APS) exhibit higher wear resistance when compared to that of conventional coatings. This study aimed to verify if HVOF-sprayed Al2O3-13wt%TiO2 coatings produced using hybrid (nano+submicron) powders could improve even further the already recognized good wear properties of the APS nanostructured coatings. According to the abrasion test results (ASTM G 64), there was an improvement in wear performance by a factor of 8 for the HVOF-sprayed hybrid coating as compared to the best performing APS conventional coating. When comparing both hybrid and conventional HVOF-sprayed coatings, there was an improvement in wear performance by a factor of 4 when using the hybrid material. The results show a significant anti-wear improvement provided by the hybrid material. Scanning electron microscopy (SEM) at low/high magnifications showed the distinctive microstructure of the HVOF-sprayed hybrid coating, which helps to explain its excellent wear performance.
Induction Plasma Deposition of Refractory Metal: Processing Parameters Optimization
Authors: Fan X. , Boulos M. , Masini G. , Kovářík O. , Bensch J. 
Published: September 2022

Abstract
To prepare a dense, defect-free deposit of refractory metals relies not only on the droplets’ state, their temperature and velocity prior to impact on the surface of substrate and/or the precedent deposited layer, but also on the surface temperature of the substrate, whereupon the droplets impact. This paper presents a comprehensive investigation, in which the particles temperature, velocity, and the substrate temperature are studied all-in-one step to understand their influence on the deposit quality. The experimental results make our knowledge of the induction plasma spray of refractory metals process more integrated. Based on our estimation on the effect of all of the three factors, a set of optimized process parameters was established and proved by applying it in producing stationary deposits and coating layers. The results obtained distinguish the induction plasma spray a unique technique, which is ideal to be utilized in refractory metals deposit.
Transition Curvature in Flattening Behavior of Plasma Sprayed Metallic Materials
Authors: Fukumoto M. , Yamaguchi T. , Yamada M. , Yasui T. 
Published: September 2022

Abstract
A variety of metallic powder particles were thermally sprayed onto the mirror polished metallic substrate surface and the effect of both substrate temperature and ambient pressure on the flattening behavior of the particle was systematically investigated. In the flattening behavior of the sprayed particle onto the substrate surface, critical conditions were recognized both in the substrate temperature and ambient pressure. That is, the flattening behavior changed transitionally on that critical temperature and pressure range, respectively. A transition temperature, Tt, and transition pressure, Pt, were defined and introduced, respectively for those critical conditions. The fact that the dependence both of transition temperature and transition pressure on the sprayed particle material had similar tendency indicated that the wetting of the substrate by the molten particles seemed to be domination in the flattening. Three dimensional transition curvature by combining both transition temperature and transition pressure dependence was proposed as a practical and effective controlling principle of the thermal spray process.
Spraying Using Magneto-Plasma-Dynamic Arc Jet Generator
Authors: Tahara H. , Ando Y. 
Published: September 2022

Abstract
In magneto-plasma-dynamic (MPD) arc jet generators, plasma is accelerated by electromagnetic body forces. Silicon nitride reactive spraying was carried out using an MPD arc jet generator with crystal silicon rods and nitrogen gas. Because higher-velocity, higher-temperature and higher-density and larger-area plasmas are produced with the MPD arc jet generator than those with conventional thermal plasma torches, nitriding of silicon can be enhanced. A dense and uniform β-Si3N4 coating 30 µm thick was formed after 200 shots at a repetitive frequency of 0.03 Hz with a discharge current of 9 kA and a substrate temperature of 700 °C. The Vickers hardness reached about 1300. Furthermore, silicon carbide and aluminum nitride sprayings were conducted with the same spraying system. Surface modification is under study with lots of chemically reactive gases. All results showed that the MPD arc jet generator had high potential for spraying and surface modification.
Relation between the Arc Root Fluctuations, the Cold Boundary Layer Thickness and the Particle Thermal Treatment
Authors: Noguès E. , Fauchais P. , Vardelle M. , Granger P. 
Published: September 2022

Abstract
In plasma spraying, the arc root fluctuations, modifying the length and density of the plasma jet, have an important influence on particle thermal treatment. These voltage fluctuations are strongly linked to the properties of the cold boundary layer, surrounding the arc column, depending on the plasma spray parameters (composition and plasma forming gas flow rate, current, etc.) and the plasma torch design (anode-nozzle internal diameter and shape, etc.). In order to determine the influence of these different spray parameters on the cold boundary layer properties and voltage fluctuations, experiments were performed with two different plasma torches from Sulzer Metco. The first one is a PTF4 torch with a cylindrical anode-nozzle, working with Ar-H2 plasma gas mixture and the second one is a 3MB torch with both a conical and a cylindrical anode-nozzle, working with a N2-H2 plasma gas mixture. Moreover, the arc voltage fluctuation influence on particle thermal treatment was observed through the measurements of temperature and velocity of particles, using an yttria partially stabilized zirconia powder with a size distribution between 5 to 25 µm.
Process Characterization of LPPS Thin Processes with Optical Diagnostics
Authors: Gindrat M. , Refke A. , Schmid R. 
Published: September 2022

Abstract
Low pressure plasma spraying (LPPS) and LPPS-Thin Film (LPPS-TF) processes cover a broad operational pressure range from typically 200 mbar down to a few millibars, filling the gap between conventional thermal spray processes, where coatings are made from the liquid phase, and conventional thin film technologies such as PVD or CVD, where coatings are produced from precursors species in the vapor phase. Using some specific parameters of the LPPS-TF process, the injected material can be partially or even completely in gaseous phase, disqualifying diagnostics based on the detection of solid or liquid particles such as the DPV-2000 (Tecnar, St-Bruno, QC, CA). In this case, other optical diagnostic tools have to be used, such as optical emission spectroscopy (OES) to characterize the LPPS-TF process. In this paper, a qualitative study of the properties of the injected material in the plasma jet using DPV-2000 and optical emission spectroscopy is presented by varying specific plasma parameters. Moreover, in some particular cases, it is shown that the combination of DPV measurements and OES can help to monitor the coating process and to improve the basic understanding of the LPPSTF technology.
Detection of Wear in One-Cathode Plasma Torch Electrodes and Its Impact on Velocity and Temperature of Injected Particles
Authors: Mauer G. , Marqués J.-L. , Vaßen R. , Stöver D. 
Published: September 2022

Abstract
Wear at the electrode surfaces of a one-cathode plasma torch changes the characteristic fluctuation pattern of the plasma jet. This affects the trajectory of the particles injected into the plasma jet in a non-controllable way, which degrades the reproducibility of the process. Time-based voltage measurements and Fourier analysis were carried out on a one-cathode F4 torch at different wear conditions to determine the evolution of wear-dependent characteristics. A significant correlation is observed between increasing torch wear and decreasing voltage roughness and high frequency noise. Furthermore, by means of particle diagnostic systems, the change in the particle velocity and temperature has been measured. The variations of the particle characteristics are significant and thus an influence on the sprayed coating microstructure is to be expected.
Non-Destructive Testing of Coatings by Surface Acoustic Waves
Authors: Berger L.-M. , Schneider D. , Großer T. 
Published: September 2022

Abstract
The steadily increasing requirements to the properties of thermal spray coatings have to lead to the development of new characterization tools, in particular for non-destructive testing. Laser acoustic surface waves relate to the most promising methods for cost-effective non-destructive testing. In this work seven HVOF-sprayed WC-based coatings were systematically studied by laser acoustic surface waves using the LAWave device. Due to short measurement and calculation times the coating can be easily multiply tested. Young`s modulus and densities of the coating were obtained by this method. The values of the Young's modulus were compared with those derived from a micro-indentation method using Vickers indents and were found to be in a good agreement. Moreover, Vickers hardness values of the coatings obtained by using different loads were compared and the phase composition was studied by X-ray diffraction. The coating porosity was determined by image analysis of optical micrographs of metallographic cross-sections. It is proposed that in the case of WC-based coatings changes in the theoretical density of the material composition due to phase transformations induced by the spray process (formation of W2C and solid solutions on their base) prevent a direct access to the porosity values.
Effect of Aluminum Additive on Friction and Wear Behaviour of Plasma Sprayed Ceramic Coatings
Authors: Tao S.Y. , Yin Z.J. , Zhou X.M. , Ding C.X. 
Published: September 2022

Abstract
In this study, three different types of Al2O3 coatings were prepared by atmospheric plasma spraying. Some physical properties of these coatings were measured. Microstructure and wear morphologies of coatings were investigated by scanning electron microscopy (SEM) and optical microscopy (OM). The tribological behaviour of various coatings against stainless steel using a block-on-ring configuration were investigated in terms of the microstructure, physical properties especially the thermal diffusivity of coatings and the evaluation of tribological heat. Results revealed that the wear resistance of coatings used in this work showed a high dependence on their thermal diffusivity rather than other properties such as porosity, microhardness and bond strength: the higher the thermal diffusivity of a ceramic coating, the better is its wear resistance.
Characterization of Coatings Sprayed with AMT200 HVOF System
Authors: Zhang G. , Liao H. , Coddet C. , Malavolta C. , Hansz B. , Keller S. 
Published: September 2022

Abstract
The development of High Velocity Oxy-Fuel (HVOF) process shows a clear trend toward the design of new gun in which high pressure and large power are expected in order to obtain a stable flame and a high powder feed rate for industrial applications. In this work, a new HVOF gun, AMT-200, was used to prepare NiCrAlY and WC-Co-Cr coatings. To optimise the spraying parameters, i.e., flux rates of oxygen and fuel gas and spraying distance, the on line control system AMT Spraying Xplorer was used. The results show that the spraying parameters play significant roles on the properties of NiCrAlY coatings. Employing optimized parameters, a dense NiCrAlY coating, with a high coating/substrate bonding strength and low oxygen content, could be obtained by this system. Moreover, thermal treatment could reduce significantly the coating porosity and increase greatly coating/substrate bonding strength. The preliminary tests on WC-Co-Cr coating indicate that dense cermet based coatings could be deposited with this system.
Testing Method for Heat Resistance Under Temperature Gradient
Authors: Takagi K. , Kawasaki A. , Itoh Y. , Harada Y. , Ono F. 
Published: September 2022

Abstract
“Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, reciprocating engines, accelerators, power switchgears etc. Three kinds of testing method, such as burner heating test, arc heating test and various beam heating tests are involved.
Investigation on HVOF-Technique for Fabrication of SOFCs (Solid Oxide Fuel Cells) Electrolyte Layers
Authors: Gadow R. , Killinger A. , Candel Ruiz A. , Weckmann H. , Öllinger A. , Patz O. 
Published: September 2022

Abstract
Thermal spray processes represent a cost effective and flexible method for the production of functional coatings by using metallurgical, ceramic and cermet materials. Due to the high kinetic energy of the impinging particles, the HVOF (High Velocity Oxygen Fuel) technique is able to produce extremely dense coatings with very low porosity. In this study, several yttria stabilized zirconia (YSZ) powders have been sprayed by HVOF for the fabrication of electrolyte layers for SOFCs (Solid Oxide Fuel Cells) applications. Coatings were characterized regarding their porosity, leak tightness and electrochemical properties. Results were compared to VPS sprayed coatings. The electrochemical behavior of the cells sprayed with the optimized set of parameters was determined applying U(i)-characteristics and impedance spectroscopy. With a destination thickness of about 40 µm, competitive leak tightness of the electrolyte and performance of the cells could be established.
Cladding of Aluminum Substrates with Nano Crystalline Solidifying Wear Resistant Iron-Based Materials
Authors: Wilden J. , Bergmann J.P. , Reich S. , Schlichting S. , Schnick Th. 
Published: September 2022

Abstract
Since many years, aluminum alloys are established as lightweight construction materials. To reach a partial wear protection for aluminum components in conjunction with seal faces, inlays, made of wear resistant materials, are commonly used. Problems concerning this approach are the necessary space and the endurance strength of the inlay - part joint. In the following paper an alternative for the replacement of the inlays by cladding with an innovative and easy to handle short arc technology will be discussed. This technology offers the potential to control the energy input into the substrate and so the formation of brittle intermetallic phases in the aluminum-steel interface as well as the thermal stresses. The usage of new nano crystalline solidifying wear resistant iron-based feedstock materials with advantageous physical and mechanical properties enables further applications beside the wear protection of surfaces, for example as metallic heat insulation layer with a low heat conductivity, close to the values of ceramics.
Dye Sensitized Solar Cells Using Titanium Oxide Photo Voltaic Devices Fabricated by Different Thermal Plasma Processes
Authors: Ando Y. , Tobe S. , Tahara H. 
Published: September 2022

Abstract
Since Dye sensitized solar cell (DSC) is a solar cell which uses anatase film as photo voltaic device, production cost of DSC can be very low in comparison with that of silicon solar cell. Besides, according to some theoretical discussion on DSC, the electric power conversion efficiency can be raised to 30%. Therefore, DSC will be mainly used in future. In this study, in order to develop a low cost fabrication process for photo voltaic device of DSC, photo-catalytic titanium oxide film depositions were carried out by thermal plasma CVD (TPCVD) and thermal spraying. As working gas for plasma jet, and substrate, Ar gas and 20mm×40mm×1mm copper plate were used. Feedstock materials were titanium tetra butoxide in TPCVD and rutile powder in thermal spraying. In the DSCs using these films, cathodes (titanium oxide coated electrodes) were located beneath the transparent anodes. Consequently, in the case of TPCVD, anatase dominant film could be deposited and the DSC using this TPCVD film could generate 50 mV in electro motive force. Furthermore, even in case of thermal spraying, though rutile powder was used, photo-catalytic coating (anatase and rutile mixture coating) could be obtained by cooling substrate during coating and post heat treatment. It was confirmed that the electromotive force of the DSC using this thermal spray coating was almost the same as that of the DSC using the TPCVD film. From these results, these thermal plasma processes was found to have high potential for DSC fabrication.
Production and Characterization of Metastable ZrO2-Al2O3 Coatings Obtained by APS + Quench
Authors: Dosta S. , Cano I.G. , Miguel J.R. , Guilemany J.M. 
Published: September 2022

Abstract
Producing nanostructured materials through metastable phases is an interesting novel route in the field of ceramic materials. Due to their small grain size and uniform structure, these nanostructured bulk materials exhibit very interesting properties. Metastable coatings can be produced starting from microstructured powders through atmospheric plasma spray (APS) technique, followed by a quenching route. The initial powders are melted during the spraying and deposited over a substrate that is quenched with liquid nitrogen (LIN) feeders, producing metastable coatings. The thermal sprayed coatings have been characterized using XRD, SEM, FESEM and EDS in the Thermal Spray Centre (CPT) of the University of Barcelona. The properties of such coatings have been also studied obtaining promising results.