bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermophysical and Microstructural Studies on Thermally Sprayed Chromium Carbide Coatings
Authors: Thiele S. , Sempf K. , Berger L.-M. , Spatzier J. 
Published: November 2022

Abstract
Cr3C2-NiCr coatings are commonly used to provide abrasion and erosion wear resistance on the surface of components, in particular for corrosive and atmospheric high-temperature environments. For these classical and new applications the knowledge of the thermophysical properties is highly important. In the present work the dependence of the heat conductivity on temperature of two HVOF-sprayed Cr3C2-25NiCr-coatings prepared by a liquid-fuelled HVOF-process from two different feedstock powders from room temperature up to 700 °C was determined. Thermal diffusivities, density functions, specific heat capacities and coefficient of thermal expansion (CTE) were measured in order to compute the heat conductivity for the coatings. All measurements were performed twice (as-sprayed and after a first thermal cycle) in order to take into account the structural and compositional changes. XRD and FESEM studies were performed in order to characterize the phase compositions and microstructures in the as-sprayed and heat-treated states. Heat conductivities (average of the two coatings) ranging from about 11 W/(mK) at 50°C up to about 20 W/(mK) at 700°C were determined. Differences between the two coatings were clearly detectable. The heat conductivity of the Cr3C2-NiCr coatings is significantly lower than determined previously for a WC-17%Co coating.
New Thermal Spray Powders for SOFC Components
Authors: Brüning B. , Gries B. , Nakadate H. , Zimmermann S. 
Published: November 2022

Abstract
In Solid Oxide Fuel Cells (SOFC), thermal spraying has become a preferred process in order to create functional and protective coatings. After a long period of research, SOFC is on the way to become a fully developed technology starting into mass production. Cost aspects of coating generation are becoming decisive. For this reason, thermal spraying has become the preferred process to apply e.g. Manganese Cobalt Iron Oxide (MCF) coatings which prevent the formation of volatile Cr oxides in the SOFC air supply and off-gas. Also Lanthanum Strontium Manganese Oxide (LSM) is now preferentially applied via thermal spraying. The presentation highlights the properties of commercially available spray powders for SOFC, their processing via different spray processes, and the properties of coatings achieved.
Nanostructured WC-Co Coatings Manufactured by Fine Powders (-10+2 µm) with Ultra-Fine Carbides (400 nm) by Means of HVOF
Authors: Tillmann W. , Hollingsworth P. , Baumann I. , Tolan M. , Paulus M. 
Published: November 2022

Abstract
Thermal sprayed WC-Co coatings are widely used for various industrial applications due to their high hardness and corresponding wear resistance. Recently, it has been reported by many researchers, that the use of agglomerated and sintered micron powders with submicron or nanosized carbides can provide the deposition of WC-Co coatings with enhanced or even superior mechanical and tribological characteristics. This can only be achieved, as long as optimized coating conditions adapted to the specific thermo-kinetic behavior of such powders are considered. However, the porosity in the coating morphology represents an inherent problem when using powders with conventional agglomerate size (10-50 µm) and high internal porosity. Consequently, a minimum coating thickness is often necessary to provide suitable wear properties, which reduces the shape or dimensional accuracy when applying such coatings to complex surfaces. In addition, a reduction in surface roughness of the coating cannot be accomplished by fine carbides, since large agglomerates are employed. In this study we used two different fine WC-12Co powders in the HVOF process to manufacture nanostructured coatings with high hardness, moderate toughness, low surface roughness and low porosity. The first powder is a fine agglomerated and sintered powder with particle size of -10+2 µm and carbides in the ultrafine range (400 nm) The second one consists in two loose mixtures of fine Co (Fisher grain size FSS = 3.5 µm) with (a) WC (FSS = 3.0 µm) and (b) WC (FSS = 0.8 µm). Statistical design of experiments (DoE) were utilized to determine main effects of spray conditions on coating properties. Mechanical properties, microstructure and the phase development has been correlated to the in-flight particle behavior. Phase analyses were performed by XRD using synchrotron radiation.
Understanding of Spray Coating Adhesion through the Formation of a Single Lamella
Authors: Goutier S. , Vardelle M. , Fauchais P. 
Published: November 2022

Abstract
Plasma spraying allows melting totally or partially micrometer sized particles, which flatten in about one is onto the substrate to build the coating by layering resulting solidified splats. The coating adhesion is essential and depends mainly on the behaviour of first lamellae in contact with the substrate. But in the plasma spray process about 108 particles/sec impact onto the substrate, and thus it is difficult to understand the role of the different spray parameters onto the coating quality. In order to get a better understanding of phenomena involved, it is necessary to study a single lamella formation. The experimental set-up is composed of a fast (50ns) two-colour pyrometer and an imaging system, comprising two fast (1 to 10 µs) CCD cameras triggered by the velocity signal of the particle in flight prior to its impact. This work is focused on alumina particles flattening onto stainless steel (304L) substrates preheated at different temperatures during different times.
Erosion Resistance of WC-12Co High Velocity Oxy-Fuel Coatings
Authors: Clavette P. L. , Nardi A. J. , Laube B. L. , Shi J. , Ely R. , Centolanza L. 
Published: November 2022

Abstract
In this work a number of different WC-12Co powder formulations were applied to coupons of steel using HVOF (high velocity oxy-fuel) and DSC (detonation spray coating) spray techniques. Two different HVOF guns and a super detonation gun (Super D-Gun ) were used to apply the coatings. The coated specimens were heat treated in an inert atmosphere at various temperatures in the range of 540°C -1000°C and subsequently characterized using optical microscopy, a Vicker’s microhardness tester, SEM (Scanning Electron Microscopy) and XRD (X-Ray Diffraction) to identify the phases generated. Additionally, in situ XRD was performed on a subset of these samples to explore the progression of the phase transformations as a function of temperature. Samples were also exposed to sand erosion with 20-30 mesh Ottawa sand at 825 feet per second to quantify performance. The work shows that the heat treatment and the transformation of amorphous metallic phases, WC and W2C to the η phase (Co6W6C) results in higher hardness and lower sand erosion rates.
Reducing the Cost of Thermal Barrier Coatings by Optimizing the Atmospheric Plasma Spray Process
Authors: Mihm S. , Duda T. , Thomas G. , Gruner H. , Dzur B. 
Published: November 2022

Abstract
The global economic growth has triggered a dramatic increase in the demand for resources over the last few years, resulting in steady price increases for energy and raw materials. In the gas turbine manufacturing sector, process optimizations of cost-intensive production steps involve a heightened savings potential and form the basis for securing future competitive advantages in the market economy. In this context, the atmospheric plasma spraying (APS) process for thermal barrier coatings (TBC) has been optimized. A constraint for the APS coating process optimization is the use of the existing coating equipment. Furthermore, the current coating quality and characteristics are not allowed to change in order to avoid new qualification and testing. Using experience in atmospheric plasma spraying and empirically gained data, the process optimization plan included the variation of e.g. the plasma gas composition and flow rate, the electrical power, the arrangement and angle of the powder injectors to the plasma jet, the grain size distribution of the spray powder and the plasma torch movement procedure like spray distance, offset and iteration. In particular, plasma properties (enthalpy, velocity, temperature), powder injection conditions (injection point, injection speed, grain size distribution,) as well as the coating lamination (coating pattern, spraying distance) are examined. The optimized process and resulting coating was compared to the current situation by several diagnostics methods. The improved process provides significantly lower costs by achieving the requirement of comparable coating quality. Furthermore, a contribution was made to a better comprehension of the atmospheric plasma spraying of ceramics and a method for future process developments was defined.
The Protectiveness of Thermally Grown Oxides on Cold Sprayed CoNiCrAlY Bond Coat in Thermal Barrier Coating
Authors: Manap A. , Ogawa K. 
Published: November 2022

Abstract
This paper presents the results of a study of the oxidation behavior of thermal barrier coating (TBC) with air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) top coat and CoNiCrAlY bond coat deposited using low pressure plasma spray (LPPS) and cold spray (CS). The TBC is subjected to isothermal oxidation and creep tests at 900 ¢XC and evaluated using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and transmission electron microscopy (TEM). The thermally grown oxide (TGO) developed in TBC with LPPS bond coat was composed of only α-Al2O3 and the TGO developed in TBC with CS bond coat is composed of α-Al2O3 and γ-Al2O3. Despite the presence of this metastable γ phase, the TGO in the CS specimens exhibits a dense microstructure and lower amounts of mixed oxides. The correlation between γ-Al2O3 and the formation of mixed oxides was investigated through the measurement of γ- Al2O3 thickness ratio and mixed oxides coverage ratio. It was found that the mixed oxides coverage ratio is inversely proportional to the γ- Al2O3 thickness ratio. Overall findings indicate that the oxidation behavior of the TBC with CS bond coat is superior compared to that of the TBC with LPPS bond coat.
Impact Conditions for Cold Spraying of Hard Metallic Glasses
Authors: List A. , Gärtner F. , Schmidt T. , Klassen T. 
Published: November 2022

Abstract
As compared to thermal spray techniques, cold spraying allows to retain metastable phases of the feedstock material like amorphous structures, due to lower process gas temperatures. Compared to crystalline metals, metallic glasses are brittle at ambient temperature but viscous at higher temperatures. Therefore, cold spray parameters must be optimized for conditions that allow softening of the amorphous spray material for successfully producing coatings. For this study, a FeCoCrMoBC metallic glass was used that in comparison to others offers advantages with respect to higher hardness, less costly feedstock powder and minimum reactivity with the environment. Necessary impact conditions were investigated to meet the window of deposition. According to calculations and cold spray experiments, neither the glass transition temperature Tg nor the melting temperature Tm can describe required conditions for bonding. Thus, a so called softening temperature between the glass temperature and the melting temperature had to be defined to calculate the critical velocity of metallic glasses. With respect to the bonding mechanism, impact morphologies could prove that a transition to viscous flow gets more prominent for harsher spray conditions. By sufficiently exceeding critical condition for bonding, coatings with rather dense microstructures can be processed at deposition efficiencies of about 70 %. The coatings have a hardness of 1100 HV 0.3, but the results also demonstrate that further work is still needed to explore the full potential for bulk metallic glasses.
Deposition of Composite LSCF-SDC and SSC-SDC Cathodes by Axial-Injection Plasma Spraying
Authors: Harris J. , Qureshi M. , Kesler O. 
Published: November 2022

Abstract
The performance of solid oxide fuel cell cathodes can be improved by increasing the number of electrochemical reaction sites. This is often done by controlling microstructures and using composite materials that consist of an ionic conductor and a mixed ionic and electronic conductor. LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ) and SSC (Sm0.5Sr0.5CoO3) cathodes were manufactured by axial-injection atmospheric plasma spraying (APS), and composite cathodes were fabricated by mixing SDC (Ce0.8Sm0.2O1.9) into the feedstock powders. The plasma power was varied by changing the proportion of nitrogen in the plasma gas. The microstructures of cathodes produced with different plasma powers were characterized by scanning electron microscopy and gas permeation measurements. The deposition efficiencies of these cathodes were calculated based on the mass of the sprayed cathode. Particle surface temperatures were measured in-flight to enhance understanding of the relationship between spray parameters, microstructure, and deposition efficiency.
LPPS Hybrid Technologies for Emerging Energy Applications – Recent Developments
Authors: Gindrat M. , Damani R. 
Published: November 2022

Abstract
Recent developments in hybrid low pressure thermal spray technologies such as Plasma Spray-Thin Film (PS-TF), PS-PVD, PS-CVD are being increasingly used to develop functional inorganic coatings and films for emerging high end energy applications. The requirements of such coatings and films are more highly specified than those of conventional plasma spray coatings. Successful film deposition therefore requires not only the development and application of novel operating parameters, but also goes hand-in-hand with tailored feedstock materials development. Targeted development by Sulzer Metco has allowed applications to evolve into fields where conventionally competitive manufacturing technologies would be applied; potentially enabling entirely new fields of plasma spray manufacturing to emerge. Such applications include corrosion protection and electrolytic films in SOFC, gas tight mixed electron and ion conducting membranes for gas separation and thin, transparent functional layers in photo-voltaic applications. This paper provides a brief overview of the status of developments of several high end emerging energy applications which are being developed using such hybrid low pressure plasma spray technologies.
Effect of Solution Chemistry on Solution Precursor Plasma Spray Deposition of LiFePO4
Authors: Chien K. L. C. , Golozar M. , Coyle T. W. 
Published: November 2022

Abstract
Solution precursor plasma spray (SPPS) is a thermal spray process in which deposits are formed by injecting solutions with the appropriate chemistry directly into the plasma. The deposits consist of grains or particles as small as ~20nm, and may be very porous or nearly dense, depending on the solution and deposition parameters. Recently, the potential of SPPS to deposit fine particle, porous coatings suitable for use as electrochemical electrodes for fuel cells and gas sensors has been demonstrated. This paper describes the efforts to deposit LiFePO4 coatings which may be of interest for Li ion battery electrodes with SPPS. In this case, along with the porosity, surface area, and microstructure of the deposited coatings, crystal structure also plays an important role in determining the performance of the LiFePO4 electrodes. Solution precursors with different solution chemistries containing lithium, iron and phosphorus ions are injected into hydrocarbon plasma issuing from a DC-arc torch. The effects of solution chemistries on coating morphologies and crystal structure were investigated. The results indicate that the porosity and crystal structure of the coatings can be tailored by selecting different additives.
The Efficient Management of Public R&D Funding in Order to Promote the Development of the Territory
Authors: Meneghetti S. , Giolli C. , Giorgetti A. , Scrivani A. 
Published: November 2022

Abstract
The current critical situation of the world economy pushes the companies to make themselves adaptable and to change their usual rigid behaviour in order to survive globalization of the market, to face the competition of the so called low cost countries (LCCs) and to overcame the current financial crisis. For the western companies, the possible way to face the movement of production to the LCCs, is to invest and increase the technological level of their products by means of effective R&D. This is even more valid for the Small and Medium Enterprises (SMEs) and is particular valid for the power generation sector. This paper addresses the policies adopted by the Public Administrations in the different countries in order to support the companies. The Public Administrations have the interest to support the companies not only in order to promote their own growth but, above all, in order to support the development of the territory where the company is located with the growth of the job numbers and the increasing of the subsuppliers activities. A review of the financial instruments available for companies in order to obtain financial help for research and innovation is provided, advantages and disadvantages are discussed. The focus is placed to the energy sector. An industrial case study is shown, related to a thermal spray shop dealing with gas turbine components, where the efficient and effective use of research allows the set up and the development of the company and also contributes to the surrounding market.
E-Learning Training in Plasma Spraying Area
Authors: Planche M.-P. , Costil S. , Montavon G. 
Published: November 2022

Abstract
The field of materials processing experiences many applications and developments in multiple industrial sectors where the used materials have to operate in most cases under extreme conditions (of temperature, pressure, reactivity of the environment, etc.). Under such conditions, he implementation of a system dedicated to the knowledge capitalization and ability concerning the use of technologies of the manufacturing processes remains today very important for the promotion of collective progresses in these fields. This is the main objective of this project which aims at promoting distance learning (e-learning) and at developing new knowledge-based systems to undergo scientific and technological skills. Currently, the research and education world is experiencing many urges of change, partly enabled and stimulated by the new possibilities offered by the Web. There is clear evidence that e-learning offers increased opportunities for training assessment leading to real benefits in terms of learner retention and achievement. This paper outlines the steps of the development of thermal spraying training supports using appropriate technologies in the thermal spraying field.
Supersonic Flame Sprayed Cylinder Liner Coatings and the Benefits of their Intrinsic Porosity
Authors: Manzat A. , Killinger A. , Gadow R. 
Published: November 2022

Abstract
To meet new regulations and specifications for internal combustion engines, new approaches to significantly decrease fuel consumption and emissions are needed. The deployment of tribologically functional coatings applied by supersonic flame spraying represent a promising technology for achieving these targets. Thermally sprayed coatings can help in improving efficiency of internal combustion engines by reducing the internal friction and improving the durability and wear resistance of the engine’s cylinder wall thereby facilitating extreme engine downsizing concepts. Thermal spraying is also capable of processing highly corrosion resistant materials like alloys and ceramics to enable the safe utilization of biofuels in modern combustion engines. In addition, specific surface structure of thermal spray coatings, including their intrinsic porosity, shows the benefit of reducing the friction by sustaining hydrodynamic friction even in spots with low relative movement, e.g. top and bottom dead center. On top, the open surface porosity can reduce the oil consumption and thereby decrease the polluting emissions of internal combustion engines. The thermally sprayed coatings were applied using HVOF and HVSFS processes deploying various materials, including novel nanostructured powders. The coated cylinders and engines have been compared to state-of-the-art components with respect to friction coefficient, wear and oil consumption.
Friction Improvement of New Generations of Engines by PTWA Cylinder Bore Coating and New Piston Rings
Authors: Schramm L. , Verpoort C. , Schwenk A. , Bobzin K. , Bagcivan N. , Schläfer T. , Theiß S. , Yilmaz K. 
Published: November 2022

Abstract
In an effort to inhibit a climate change, the European Union has decided to reduce the CO2 emissions by approx. 30% by year 2020, as compared to the level of emissions in year 1990’s. In general, traffic is responsible for 20% of all CO2 emissions and 84% of those emissions result specifically from road traffic. In accordance with the present targets of the CO2 emission reduction the automotive industry has to meet strict regulations. The strict emission goals can only be reached by weight reduction of the vehicle and by an improved efficiency of engine and drive train. Close to 50% of the friction losses in a combustion engine result from the interaction between the piston ring and the cylinder bore surface. Therefore the cylinder bores as well as the piston rings were coated with new, low-friction materials. The friction behaviour was characterized in linear reciprocating tribometer-test in order to identify the best combination of bore and ring coatings.
Thermal Coating of Cylinder Bores Needs Approved Processes of Pre and Post Treatment
Authors: Flores G. 
Published: November 2022

Abstract
The application of thermal coatings in cylinder bores is depending on above all functionality, process reliability and economy of pre treatment of the substrate surfaces. Different removing processes like water jetting or sand blasting are increasingly substituted by mechanical machining. Thereby great importance is attached to functionality and degree of automation. For an assured engine function, high bond strength is required. The roughening process as a modified cutting machining meets the requirements of modern production lines. Removing overspray after thermal coating by a water jetting process, is a further contribution for a higher automation degree. The final machining of sprayed surfaces is effected by a multi stage honing process. The composite structures of thermal coated layers call for high performance diamond abrasives. The finished functional cylinder surface comprehends cavities of thermal coated layer and smooth honing pattern. The technological description of roughening and honing, the process components as well as the machining results will be presented. Pre and post treatment are essential processes, which enable the application of high performance thermal coating materials in friction optimized combustion engines.