bluuebunny/crossref_metadata_2025_split huggingface dataset:
Processing and Properties of Hybrid YSZ Coating Deposited by Thermal Plasma Directed Vapor Deposition
Authors: Lavaud T. , Vardelle M. , Fauchais P. , Menuey J. 
Published: September 2022

Abstract
The aim of this study is to develop for thermal barrier applications a new process in which coatings exhibit properties between those of APS and EBPVD. This process includes two conventional D.C. plasma torches working in a chamber whose pressure can vary between 30 and 100 kPa. Micro-sized yttria stabilized zirconia powders are injected in both plasma jets to vaporize them, at least partially, and produce finely-structured coatings from vapor and micro-droplets deposition. The torch arrangement allows separating the vapor and the very small particles (less than 1 µm) from the partially vaporized bigger ones. The diagnostics are based on optical emission spectroscopy, pyrometry, imaging of particles trajectories and coating microstructural characterization.
Microstructural Characterization of Plasma-Sprayed YSZ/AI2O3 Thermal Barrier Coatings
Authors: Saral U. , Toplan N. 
Published: September 2022

Abstract
In the present study, yttria-partially-stabilized zirconia (YSZ)/Al2O3 coatings, which are used for jet engines, gas turbines and diesel engines were coated with thermal barrier coatings (TBCs) to provide high thermal resistance, reduce the metal surface temperatures, and increase component durability. The effect of alumina addition from 0 to 80 wt% on the properties of plasma sprayed YSZ coatings was investigated. The coatings were produced using a METCO 3MB plasma spray gun on stainless steel and graphite substrates. Scanning electron microscopy (SEM) was used to analyze the microstructures of the coated samples. The microhardness was investigated depending on the alumina contents. Vickers hardness on cross section of coatings was observed to increase with the increase in alumina mixing ratio. The presence of alumina phase commonly improves the mechanical properties of YSZ.
Tools for Online Monitoring of Failure Evolution of Thermal Barrier Coatings in Gas Burner Thermal Cycling Rig Environment
Authors: Mack D.E. , Vaßen R. , Stöver D. 
Published: September 2022

Abstract
One major shortcoming of thermal barrier coatings applied to gas turbine components is the spallation of the ceramic coating under mechanical stress developing during thermal cycling environments. In order to study the evolution of failure and the expectancy of lifetime under realistic conditions cycling burner rig tests are a well established matter of choice. In the same way the techniques of acoustic emission (AE) testing and infrared (IR) thermography have been widely proofed to provide insight to microscopic crack formation and localization of hidden delaminations, respectively. Both techniques can be utilized to record the evolution of microscopic and macroscopic defects in advance to the apparent failure. Indirectly, this knowledge allows to verify and to improve lifetime models. The aim of this study is to expand the use of AE and IR testing as a rugged in-situ monitoring tools for combustion driven cycling rigs and to provide spatial resolved information on thermal load and failure evolution of the TBC in those tests. For a successful application to an experiment using a gas fired and air cooled burner rig some it is necessary to overcome some limitations which are mainly due to the high level of interfering signals under those experimental conditions.
Thermal Conductivity of AlSi/Polyester Abradable Coatings
Authors: Bolot R. , Seichepine J.L. , Vucko F. , Coddet C. , Sporer D. , Fiala P. , Bartlett B. 
Published: September 2022

Abstract
Abradable seals are used in aerospace applications to control the overtip leakages between the blades of an engine rotor and its static parts. To achieve the combination of properties required, these seals have been developed with thermally sprayed coatings and are generally elaborated from a range of two or three phase powder mixtures. In the present study, the thermal conductivity of thermally sprayed AlSi/Polyester abradable coatings produced with Metco 601 NS and Durabrade 1605 powders was measured and investigated using finite element and finite difference methods based on two-dimensional structures obtained from micrographs. The computed values were compared to the experimental results.
Valence Band XPS and FT-IR Evaluation of Thermal Degradation of HVAF Thermally Sprayed PEEK Coatings
Authors: Patel K. , James B.J. , Hyland M.M. 
Published: September 2022

Abstract
Coatings of poly(ether-ether-ketone) (PEEK) have been produced using the high-velocity air fuel (HVAF) thermal spray technique. These coatings have been produced at 50 and 100 mm nozzle lengths and 200, 300, and 400 mm gun-to-substrate distances on stainless steel 304 substrates. The techniques used to characterize and determine the extent of thermal degradation of the PEEK coatings were valence-band XPS and FTIR-ATR. Valence-band XPS showed that, in general, minimal degradation of the PEEK occurred during the HVAF thermal spraying process. FTIR-ATR results showed that more surface degradation of the PEEK coating occurred at the 200 mm gun-to-substrate distance for both nozzle lengths than at the larger gun-to-substrate distances. Specifically, absorption bands appeared at 2918 and 2850 cm-1, which correspond to alkane –CH2– asymmetric stretching modes. The resolution of the 672 cm-1 peak, which corresponds to C–H vibrations on the phenyl ring, increased from one to two peaks in the spectra of the 200 and 300 mm gun-to-substrate runs. This indicates a structural change in the phenyl ring, possibly indicating a change in the extent of crystallization of the PEEK polymer.
Spraying Process, Microstructure, and Relaxation Stress Behavior of Cylindrical Standalone YSZ Coatings with and without Segmentation
Authors: Karger M. , Vaßen R. , Stöver D. , Petorak C. , Trice R. 
Published: September 2022

Abstract
Segmentation cracked coatings are promising candidates for thermal barrier coatings (TBC) because of their high strain tolerances. By atmospheric plasma spraying (APS), cylindrical stand-alone YSZ coatings with and without segmentation cracks were fabricated. The diameter of the tubes was 10 mm, and the thickness of the coatings approximately 1 mm. The segmentation crack densities were in the range up to 3.5 cracks/mm, while the porosity amounted for all coatings between 5% and 7%. Further details of the spraying process and the obtained microstructures will be given and discussed. The samples were tested in an uniaxial high temperature compression rig to measure the stress relaxation. The comparison of the stress relaxation measurements yielded a different performance of segmented and non-segmented coatings with advantages for the cracked ones. It was observed that the cracks increase the resistance to stress relaxation.
Phase Stability and Structure of Conductive Perovskite Ceramic Coatings by Thermal Spraying
Authors: Lagerbom J. , Nikkilä A.-P. , Kylmälahti M. , Vuoristo P. , Kanerva U. , Varis T. 
Published: September 2022

Abstract
Perovskites are considered as potential materials in solid oxide fuel cells (SOFC) for different reasons at different parts of the fuel cells. Perovskites such as La0.8Sr0.2MnO3 (LSM) and other compositions are electrically conductive which is necessary for SOFC applications. One possible application is protection coating for interconnect plates (bipolar plate) to avoid chromium oxide evaporation from the surface of ferritic stainless steel. Different commercial and experimental perovskite powders were sprayed by plasma and HVOF spraying under different spray conditions. Spraying of pervoskites was found to be challenging and required careful parameter optimization in both spray methods. Microstructure and phase structure of the coatings were investigated. A very fine crack structure, possibly caused by low mechanical strength and low ductility of the compounds, was easily formed in coatings prepared by plasma and HVOF spraying. Spraying method, parameters and spraying atmospheres were found to affect the stability of the perovskite compounds due to low chemical stability at high spray temperatures. Oxygen deficiency or oxygen surplus was concluded to cause distortion of the compounds crystal structure, causing thus shifting of XRD-peaks due to change of lattice parameters. Electric conductivity was affected by the crystal structure.
Anode SOFCs Produced by Suspension Plasma Spraying: Interests and Prospects
Authors: Marchand O. , Rampon R. , Bertrand G. 
Published: September 2022

Abstract
In order to achieve Solid Oxide Fuel Cells (SOFC) with reduced costs, the atmospheric plasma spray process (APS) could be an attractive technique. However, it is difficult to produce plasma sprayed coatings with the appropriate porosity for the electrodes and full density for the electrolyte. The spray process has been adapted by providing a suspension or a powder as feedstock material combined with optimized spray conditions to manufacture SOFC layers with required compositions, microstructures and properties. Suspensions or powders were injected in a plasma jet originating from a conventional torch (F4) implementing external devices. By using optimized suspensions of nickel oxide (NiO) and yttria stabilized zirconia (YSZ) in ethanol, porous anodes have been produced with thicknesses around 50 µm. By the same way aqueous suspensions of yttria stabilized zirconia (YSZ) powders have been prepared to achieve a fine layer as electrolyte to produce the first half cells and the porous cathode layers based on lanthanum strontium manganite (La0.8Sr0.2MnO3 or LSM) have been manufactured by conventional atmospheric plasma spraying of powders.
Cold Spraying Technique to Process Nanomagnetic Coatings
Authors: Cherigui M. , Fenineche N. , Liao H. , Coddet C. , Li W. , Ji V. 
Published: September 2022

Abstract
The cold gas dynamic spray process, or cold spraying (CS), represents a radical departure from conventional thermal spray (TS) methods in that the deposition process relies purely on kinetic energy rather than on a combination of thermal and kinetic components. A potential advantage of this process over TS is the ability to generate dense coatings retaining initial material chemistry and phase composition with a very little oxidation. Also, low temperature process (no bulk particle melting) eliminates solidification stresses and enables thicker coatings. However, hard brittle materials like ceramics can not be sprayed without using ductile binders. In this study, magnetic alloys such as FeSiBNbCu also called Finemet and FeSiBNbCu-Al with various percentages of Aluminum coatings were synthesized using cold spray technique in order to produce ferromagnetic materials. Ultra-fine grain coatings were obtained using FINEMET nanostructured powders mixed with Aluminum as ductile binder in order to improve adherence. Magnetic measurements revealed a soft magnetic character for all the powders and the coatings. 25% of Al was considered as ideal to produce a homogenous coating with suitable magnetic properties.
Development of Ceramic Composite Coatings with Titania Nanofibers
Authors: Watanabe M. , Chivavibul P. , Komatsu M. , Kuroda S. 
Published: September 2022

Abstract
In recent years, nano alumina/titania ceramic composite coatings have been investigated and exhibited very attractive properties in several mechanical applications such as wear resistance. One of the reasons for significant improvement of those coatings properties is considered to be “nanostructure” preserved in the coating during depositions. Thus, it is of interest to introduce nanostructure with high aspect ratio into coatings and to investigate the effects on the coating properties, especially fracture properties. In this study, alumina/titania composite powders were fabricated by spray dry procedure, which consist of the alumina nano particle (~50nm) and the titania nano fibers (diameter 100~200nm, length 2~3µm). The developed powders were sprayed by APS process. The deposited coatings contain fibrous titania structures which were not melted during deposition. Fracture resistance was evaluated as a function of a crack length by Double Cantilever Beam (DCB) Test for the coatings fabricated under various spray conditions and corresponded to the microstructure.
Preparation and Characterization of Nickel Clad h-BN Composite Powders for Abradable Sealing Coating
Authors: Liu J. , Yang Z. , Wang L. , Yan S. , Zhang J. , Lin F. 
Published: September 2022

Abstract
Nickel clad hexagonal boron nitride (h-BN) powders were prepared by reducing nickel ions from a solution under hydrogen pressure in the presence of ammonia as a complexing agent, and plasma spraying was carried out to deposit the corresponding coating. The microstructure, morphology and phase composition of the powders and the coating were characterized by optical microscope (OM), Scanning Electronic Microscope (SEM) and X-ray Diffraction (XRD), respectively. The results show that alkali solution pretreatment and activation procession are necessary for acquiring a dense and uniform nickel coating on the surface of the h-BN particles, and the h-BN particles are distributed well throughout the coating with the porosity of about 26%, which indicate that the coating was potential for abradable sealing application.
Particle Trajectories by Arc Spraying with Cored Wires
Authors: Tillmann W. , Vogli E. , Abdulgader M. , Gurris M. , Kuzmin D. , Turek S. 
Published: September 2022

Abstract
To use the manifold possibilities that arc spraying offers to deposit wear resistance layers, the knowledge of the particle formation and their characteristics are necessary. The work is focused on studying the particle trajectories during arc spraying with cored wires. Different cored wires under various spraying parameters are investigated by means of a high speed camera. Particle properties in-flight, such as velocity and temperature are determined. Correlation between particle trajectories and particle characteristics at different spraying conditions are established. At the same time, the particle-laden gas flow is simulated numerically and the computed solutions are used to illustrate the utility of the proposed CFD model and compared with experimental results. The employed mathematical model represents a system of macroscopic conservation laws for the continuous gas phase and for the gas-solid mixture. This formulation makes it possible to circumvent the numerical difficulties associated with the implementation of a (potentially ill-posed) two-fluid model. The discretization in space is performed using a high-resolution finite element scheme based on algebraic flux correction in terms of local characteristic variables. The artificial diffusion operator is constructed on the discrete level and fitted to the local solution behavior using a multidimensional flux limiter of TVD type.
Study on Corrosion Resistance Behaviors of Zn, Al, Zn/Al 85/15 Coatings Produced by Twin Arc Spray Technique on Steel
Authors: Cevher O. , Gulec A. , Turk A. , Ustel F. , Yilmaz F. 
Published: September 2022

Abstract
Twin wire arc sprayed Zn, Al and Zn/Al 85/15 coatings were investigated for comparison of their corrosion resistance, electrochemical behavior. The Zn, Al and Zn/Al 85/15 coatings possess prominent electrochemical passivation behavior. Oxide formation mainly onto the coating surfaces were identified with energy-dispersive X-ray analysis and were believed to be responsible for the passivation phenomena observed in the electrochemical polarization. Zn and Al are more negative in electrochemical potential than iron. Zn coatings act as a sacrificial anode and providing cathodic protection. Aluminum shows passive corrosion protection according to stable oxide layer occurs on coating surface. Zn/Al 85/15 coating show two corrosion protection mechanisms together. In this study, steel samples were coated with Zn, Al and Zn/Al 85/15 in optimum conditions by wire arc spraying technique. These coatings were investigated behaviors of polarization and corrosion resistance with electrochemical test.
The Effect of Process Parameters on the Microstructure and Mechanical of Arc Sprayed Zn, Al, Zn/Al 85/15 Coatings
Authors: Gulec A. , Turk A. , Ustel F. , Yilmaz F. 
Published: September 2022

Abstract
Zn and Zn/Al coatings were manufactured by using twin wire arc spray (TWEA) system under various gas pressure and current. Microstructure, hardness, surface roughness and adhesion strength of the coatings were investigated by using standard characterization methods. Test results show that increasing atomizing gas pressure increased mechanical properties and surface quality. The process current had an important role on microstructural, mechanical properties and surface quality.
Cavitation Resistance and Mass Loss Mechanism in Coatings Deposited by Thermal Spraying
Authors: Pukasiewicz A. , Capra A. , Paredes R. 
Published: September 2022

Abstract
The cavitation erosion result mass loss. Welding is the most common technique used to recover the geometrical profile of the blades. However it is known that tensile residual stress can develop. The search for manufacture process that could reduce or eliminate the residual stress level will contribute for a longer life service. The target in this study to evaluate the potential of ASP thermal spray to recover surfaces. The influence of processing parameters on the cavitation resistance and mechanisms was evaluated for three alloys, AWS309LT1, AWS410NiMo and a Co stainless steel known as Cavitec. Coatings were analyzed by optical and electronic microscopy, microhardness and cavitation tests regarding the effect of air pressure. The results showed that lamellae morphology, oxide volume fraction and cavitation resistance were modified by the ASP parameters. The increase in the pressure modified the oxide fraction from 26 to 37% in AWSI309LT1, 23 to 31% for AWS410NiMo and 16 to 23% for Cavitec. Mass loss varied from 3.5 to 4.8 mg/h for AWSI309LT1, 6.65 to 18.19 mg/h for AWS410NiMo, and 3.4 to 4.0 mg/h for Cavitec; the best performance occurred with Cavitec and was associated with higher pressure of deposition and minor oxide volume fraction.
Substrate and Powder Preheat Effects on the Kinetic Spray of Hard Metal and Composite Coatings on Cast Iron
Authors: Powell N.E. , Patel N. , Elmoursi A.A. , Zhao Z.B. , Gillispie B.A. , Fuller B.K. 
Published: September 2022

Abstract
We investigate the sprayability of various hard metal and composite powder coatings via kinetic spray on cast iron by utilizing both powder and substrate preheat. These coatings include copper, a copper-zirconia composite, nickel, a zinc-nickel composite, and Ti6Al4V alloy. Using the kinetic spray process the coatings were applied to a cast iron substrate which was ground and sand blasted prior to spray. Analysis performed on powders and coating includes: cross-sectional microscopy, hardness of powders and substrate, substrate temperature as a function of heating and cooling times, and adhesion at the coating/substrate level. Results include spray parameters to allow for nickel and copper coatings to be developed on cast iron, adhesion strength as a function of powder hardness, porosity of nickel and Ti6Al4V coatings, and incorporation rates of zirconia in a copper matrix on cast iron. This is an attempt to spray hard powders on a hard substrate. Harder particles are more difficult to spray because they require more energy to plastically deform. Therefore the hardness of the particles plays a significant role in the deposition of a coating. Similarly, harder substrates are more difficult to spray on. This work demonstrates techniques that make spraying hard particles on hard substrates possible.
Formation of NiAl Intermetallic Compound by Cold Spraying of Ball-Milled Ni/Al Alloy Powder Through Post Annealing Treatment
Authors: Zhang Q. , Wang X. , Ren Z. , Yang G. , Li C. , Li C. 
Published: September 2022

Abstract
Ni/Al alloy powders were synthesized by ball milling of nickel-aluminum powder mixture with a Ni/Al atomic ratio of 1:1. Ni/Al alloy coating was deposited by cold spraying using N2 as accelerating gas. NiAl intermetallic compound was evolved in-situ through post-spray annealing treatment of cold-sprayed Ni/Al alloy coating. The effect of annealing temperature on the phase transformation behavior from Ni/Al mechanical alloy to intermetallics was investigated. The microstructure of the mechanically alloying Ni/Al powder and NiAl coatings was characterized by scanning electron microscopy and X-ray diffraction analysis. The results show that a dense Ni/Al alloy coating can successfully be deposited by cold spraying using the mechanically alloyed powder as feedstock. The as-sprayed alloy coating exhibited a laminated microstructure retained from the mechanically alloying powder. The annealing of the subsequent Ni/Al alloy coating at a temperature higher than 850°C leads to the complete transformation from Ni/Al alloy to NiAl intermetallic compound.
Low Pressure Gas Dynamic Spray of Polymer Doped Nanoparticle Contained Feedstocks
Authors: Maeva E. , Leshchinsky E. , Beneteau M. , Villafuerte J. , Maev R. 
Published: September 2022

Abstract
A new approach is explored to achieve the aluminum alloy powder layer from nanoparticle contained metallic powder mixture feedstock by Low Pressure Gas Dynamic Spray (LPGDS) or Cold Spray (LPCS). In this approach, mixtures of micron-sized aluminum powder (average size of 10 µm) and alloying nano-powder of Cu, Si and TiC (200-500 nm), at appropriate proportions to compositions of Al-5wt%Cu, Al-5wt%Cu-0.75wt%Si and Al- 5wt%Cu-5wt%TiC with polymer binder were prepared by stirring. Then, the powder mixture was compacted into pellets, dryed, and further milled to obtain the particle agglomerates (average size of 50 µm) . The powder feedstock were sprayed by LPCS. In this paper, we investigate the spraying behavior Al-based nanoparticle contained powder mixtures the microstructural development and mechanical properties of deposited layers using a microindentation, scanning probe microscopy, scanning electron microscopy and energy dispersive X-ray analysis.
Effect of the Increase in the Entrance Convergent Section Length and Geometry of the Gun Nozzle on Properties of Cold Sprayed Copper and Titanium Coatings
Authors: Sakaki K. , Takahata M. , Takeda K. , Shinkai S. , Hosono T. , Shimizu Y. 
Published: September 2022

Abstract
Nozzle geometry influences gas dynamics, such as gas density, velocity and temperature, making sprayed particle behavior one of the most important parameters in cold spray process. Gas flow at the entrance convergent section of the nozzle takes place at relatively high temperature and are subsonic. Thus, this region is a very suitable environment for heating spray particle. In this study, numerical simulation and experiments were conducted to investigate the effect of nozzle contour (convergent –divergent and convergent-divergent-barrel), entrance geometry of convergent–divergent nozzle and powder injection position at nozzle on the cold spray process. The process changes inside the nozzle were observed through numerical simulation studies and the results were used to find a correlation with coating properties. A copper and titanium powder was used in the experiments. Working gas (is nitrogen) pressure and temperature at nozzle-intake were 3MPa and 623K, respectively. In addition, the change in the nozzle contour and the change in the entrance convergent section length of the gun nozzle were found to have a slight effect on the coating microstructure. Powder injection position was also found to influence deposition efficiency and coating properties. Deposition efficiency of both copper and titanium increase with increasing the length of the convergent section of the nozzle.