bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Feedstock Mixing Composition on the Cold Sprayability of Bimodal Size 316L/Fe Powder Mixtures
Authors: Chu Xin , Che Hanqing , Yue Stephen , Vo Phuong 
Published: October 2022

Abstract
In this study, 43 μm 316L stainless steel and 23 μm commercial purity Fe feedstocks were used. The following coatings were made by cold spray: single component 316L, Fe, and their binary composites with nominal compositions of 20 wt.% Fe (20Fe), 50 wt.% Fe (50Fe) and 80 wt.% Fe (80Fe). The coatings were characterized (microstructure, flattening ratio, composition) and the cold sprayability metrics (DE, porosity, coating cohesion strength) were analyzed. Results show that the single component 316L coating has a much better DE and coating cohesion strength, and a slightly lower porosity as compared with the Fe coating, whereas all the composite coatings have the similar cohesion strength. Moreover, the 20Fe coating features the highest porosity and the lowest DE; 50Fe coating features the lowest porosity; and the 80Fe coating features the highest DE. To characterize the feedstock mixture composition, in addition to the usual approach of weight or volume fraction, the ratio of the 316L and Fe particle numbers in a mixture (i.e. particle number fraction), was calculated. Using this metric, the effects of the feedstock mixing composition on the cold sprayability of bimodal size 316L/Fe powder mixtures can be better explained.
Analysis and Optimization of the HVOF Process by Artificial Neural Networks Model
Authors: Meimei Liu , Zexin Yu , Chaoyue Chen , Hanlin Liao , Sihao Deng 
Published: October 2022

Abstract
In the High Velocity Oxygen Fuel (HVOF) technology, the coating properties are sensitive to the behaviors of in-flight particles, which are mainly influenced by the processing parameters. However, due to the complex chemical and thermodynamic reactions, the real-time optimization of the coating properties during the HVOF process is still a challenging issue. This study focused on establishing an Artificial Neural Networks (ANN) model to analyze the influence of the processing parameters on the characteristics of in-flight particles. Hydroxyapatite (HA) powders were selected to deposit onto the stainless steel substrates via an improved HVOF spraying system. Combined with an Accuraspray-g3 system applied to acquire the temperature and velocity of inflight HA particles, the artificial neural network algorithm was well trained to predict the velocity and temperature of in-flight particles. The relationship between the variations of the operating parameters (gas flow rates and fuel-to-oxygen ratio) and the behaviors of in-flight HA particles was investigated, which therefor contributes to analyzing and optimizing the mechanical performance and crystallinity of the HA coatings.
Deposition of Lamellae Well Bonded Dense Ceramic Coatings by Plasma Spraying Through Materials Design
Authors: Li Chang-Jiu , Zhang Qi-Lan , Yao Shu-Wei , Yang Guan-Jun , Li Cheng-Xin 
Published: October 2022

Abstract
It is usually difficult to deposit dense ceramic coatings with splats well bonded by plasma spraying at room temperature. Following the recent research progress on the splat interface bonding formation, it was found that there is a well defined relationship between the critical bonding temperature and materials melting point. Thus, it was proposed to control the lamellae bonding through the deposition temperature. In this study, to examine the feasibility of the bonding theory, a novel approach for the development of coating microstructure through materials design is proposed. Accordingly typical ceramic materials were selected of relative low melting point for plasma spraying of dense coating with well bonded splats. The experiment was conducted by using K2Ti6O13 for splat deposition at ~110°C cooling down from a higher temperature to avoid substrate adsorbates and coating was deposited at room temperature in ambient temperature without substrate preheating. Results show that the splat is fully bonded with a ceramic substrate, while the coatings present a dense microstructure with a similar fracture morphology to sintered bulk ceramics. Moreover, the erosion test at 90° further confirmed the formation of a ceramic coating with lamellae fully bonded.
Investigation of High Temperature Compressor Abradable Coatings for Gas Turbine Applications
Authors: Tan Winnie , Zois Dimitrios , Wilson Scott , Dorfman Mitchell R. 
Published: October 2022

Abstract
Abradable coatings are typically applied on the compressor section of gas turbines to reduce air leakage and increase compressor performance. In pursuit of engine efficiency, the service temperatures of the components are higher than before. The use of nickel-graphite coating in compressor applications in higher temperature environments diminishes the abradable property of the coating. In the current study, a series of abradable coatings were prepared with combustion and plasma spray methods and tested at gas turbine conditions. Coating microstructure, hardness, abradability, and erosion resistance was investigated and compared against conventional nickel-graphite coating. In addition, coatings were aged to mimic the aging cycle in industrial gas turbines and compared to as-sprayed coating properties.
TEM Studies of a Nano-Crystalline Cold Sprayed Ni-20Cr Coating
Authors: Kumar M. , Singh H. , Singh N. 
Published: October 2022

Abstract
In the current work a nano-crystalline Ni-20Cr coating was developed on a boiler tube material by cold-spray process. The coating powder was synthesized in-house by mechanical milling using a planetary ball mill. The average crystallite size of the developed powder was calculated to be 10 nm. The crystallite size of the coating was found to be 18 nm, and hence the retention of nano-crystallinity in the coating was established. However the grain growth occurred to some extent, which may be due to temperature rise involved in the cold spray process. A detailed TEM analysis of coated samples before and after exposure to high temperature oxidation was carried out.
Thermally Sprayed Slippery and Icephobic Surfaces
Authors: Niemelä-Anttonen H. , Koivuluoto H. , Kylmälahti M. , Laakso J. , Vuoristo P. 
Published: October 2022

Abstract
Minimizing ice adhesion and preventing ice accumulation on different surfaces has remained in scientific focus from the mid 1900’s. Decades after, scientists are combatting the same challenges, which only outlines the complex nature of ice and ice adhesion related research. One approach to exploit passive coating technology for low ice adhesion utilizes slippery surfaces that combine porous solid material with lubricating liquid. This study presents a novel method in creating functional slippery liquid infused porous surfaces, SLIPS, by exploiting flame spray technique. We demonstrate the functionality of these thermally sprayed SLIPS in ice adhesion and wettability. The ice adhesion results confirmed the potentiality of thermally sprayed SLIPS as ice repellent surfaces with an order of magnitude lower ice adhesion strength compared to polished stainless steel.
Effect of Molten Particle Temperature on the Bonding Formation During Plasma Spraying of Metal Alloy Coatings
Authors: Wang Jun , Tian Jia-jia , Li Chang-Jiu 
Published: October 2022

Abstract
Molten droplet temperature is a dominant factor influencing the bonding formation at the interface between splats during plasma spraying. In this study, the effect of molten droplet temperature on the interface bonding formation between nickel-base alloy splats was investigated. One novel shellcore- structured Mo-clad NiCr powder and conventional NiCr powder were used as the feedstock. Stainless steel with surface polishing was used as the substrate. The NiCrMo particle with a temperature over 2647 °C was generated by plasma spraying in comparison with that about 2167 °C for NiCr droplet. The molten droplet temperature when it impacted on the substrate surface was changed continuously by changing spray distance. The particle temperature was measured by DPV2000 and the interface bonding state was characterized by the cross-section samples of splat-substrate interface prepared by FIB. Results show that the interface bonding ratio can be increased from ~40% to 80% when the average molten droplet temperature is increased from ~2167 to 2647 °C.
Numerical Study on Particle Trajectories Close to the Substrates in Thermal Spray Processes with High-Kinetic and Low-Pressure Conditions
Authors: Mauer Georg , Vaßen Robert 
Published: October 2022

Abstract
In thermal spray processes, the interaction between the gas jet and the particulate feedstock can affect the coating build-up mechanisms considerably. Especially under high-kinetic and low-pressure conditions, small particles are subjected to rapid deflection and velocity changes close to the substrate. In this work, numerical studies were performed to investigate the particle trajectories in the substrate boundary layers (BL). Typical conditions for suspension plasma spraying (SPS) and plasma spray-physical vapor deposition (PS-PVD) were taken as a basis. Particular importance was attached to the consideration of rarefaction and compressibility effects on the drag force. The particle impact conditions in the different thermal spray processes are compared. Possible effects on the resulting coating build-up mechanisms and microstructure formation are discussed.
Utilizing Big Data Informatics for Thermal Spray Materials Design
Authors: Cheney Justin 
Published: October 2022

Abstract
Utilizing big data to govern decisions is becoming increasingly valuable and the thermal spray process is no exception. The thermal spray process is unique as a material process in its capability to employ a wide range of advanced materials technologies: metals, ceramics, cermets, and oxides among others. Like any process, the thermal spray technology is most effective when utilizing material feedstock which is specifically designed for thermal spray. This paper will discuss how big data techniques can be employed to design disruptive materials technology. The thermal spray process presents unique challenges to modelling and simulation work due to the inherent complexity of the process. However, these challenges offer the opportunity to develop materials tailored for specific thermal spray processes to yield improved coating performance. Furthermore, big data material informatics can significantly accelerate the discovery of new alloy solutions. More than 100 years of experimental research underpins the science employed, but modern computational tools and materials informatics principles enable new decision strategies to be utilized. The big data approach relies on calculations which predict the microstructure of millions of alloy compositions and utilizing proprietary data mining algorithms to identify unique materials spaces which would never be discovered experimentally.
Internal Diameter Coating Processes for Bond Coat (HVOF) and Thermal Barrier Coating (APS) Systems
Authors: Tillmann W. , Schaak C. , Hagen L. , Mauer G. , Matthäus Thermico G. 
Published: October 2022

Abstract
Current developments in different industrial sectors show an increasing demand on thermally sprayed internal diameter (ID) coatings. But up to now, the research focus is mainly on conventional processes such as arc spraying and plasma transferred wire arc spraying (PTWA), especially for cylinder liner surfaces. However, efficient HVOF and APS torches are meanwhile available for ID applications. Thus, in the present work, the focus of research is on the ID spraying of bond coats (BC) and thermal barrier coatings (TBC) for high temperature applications. An HVOF-ID gun IDCoolFlow mono with a N2 injection was used to spray dense BCs (MCrAlY). The TBCs (YSZ) were sprayed by applying an SM-F100 Connex APS torch. Initially, flat steel samples were used as substrates. The morphology and properties of the sprayed ID coating systems were investigated with respect to the combination of different HVOF and APS spray parameter sets.
Ballistic Testing of a Double-Layer Shaped Charge Liner Fabricated by Kinetic Spraying
Authors: Lee Seungtae , Kim Jaeick , Lee Changhee , Lee Seong , Kim Sijo 
Published: October 2022

Abstract
Shaped charge is a weapon that is devised to penetrate armor. The explosion performance of it was relatively low. The liner, which is the core component of shaped charge, is generally formed as Cu material because of good penetration ability. The double-layer liner was designed to increase the explosive power of the shaped charge and to enhance the performance of the weapon through the explosion after penetration. Reactive Al and Al-Ni coating layers were successfully deposited on the cone-shaped Cu liner via kinetic spray to fabricate a double-layer liner. A ballistic test was conducted to compare the explosive power between single Cu liner and double layer liners. Alumina and intermetallic compound of Al-Ni, which are evidence of the exothermic reaction, were investigated by EDAX, XRD techniques. Al2O3 and AlNi were detected on 4th target plate, which means that an explosion occurred after penetration. The explosive power of the liners was compared by measuring the penetration area of target plate and the number of broken support bolts. The explosive power of double layer liner was larger than that of the single Cu liner.
Multivariate Analysis of the Influence of Process Parameters on Suspension Plasma-Sprayed Coatings
Authors: Zhao Yongli , Peyraut François , Planche Marie-Pierre , Liao Hanlin , Montavon Ghislain , Ilavsky Jan , Lasalle Audrey , Allimant Alain 
Published: October 2022

Abstract
Suspension plasma spray (SPS) is far more complicated than conventional plasma spray and requires a deep knowledge about the influence of process parameters and their correlations. In this study, YSZ coatings were manufactured by SPS with six different process parameters such as plasma power, suspension mass load, original powder size, substrate surface topology, spray distance, and spray step. Afterwards, the porosity of as-prepared coatings was investigated by image method and X-ray transmission technique. A multivariate analysis on the collected experimental data was carried out by employing mathematical statistics methods. The results showed that: 1) Coating porosity has a negative correlation with plasma power and suspension mass load and a positive correlation with the original powder size, spray distance, spray step, and substrate roughness; 2) Spraying distance is the main factor affecting to coating porosity, followed by suspension mass load and substrate surface roughness, respectively. A linear model for porosity prediction was developed and was verified by experiments. The mechanism by which process parameters influence coating porosity is also discussed.
Suspension High Velocity Oxy Fuel (SHVOF) Thermal Spraying of Cr2O3 and Cr2O3 with Graphene Platelets for Dry Sliding Wear Protection
Authors: Pulsford J. , Bai M. , Hussain T. 
Published: October 2022

Abstract
Thermally sprayed Cr2O3 coatings have been shown to provide excellent protection against wear in many engineering applications. These coatings are traditionally applied using air plasma spray technology; however, suspension high velocity oxy fuel thermal spraying (SHVOF) is a promising method to improve coating properties as this technique enables powder feedstocks too small to be processed by mechanical feeders to be sprayed, allowing the production of coatings with improved density and mechanical properties. Furthermore, the addition of graphene nanoplatelets (GNPs) to the liquid feedstock has been shown to improve the mechanical properties of SHVOF sprayed ceramic coatings. In this study, an aqueous based nanometric Cr2O3 suspension and a Cr2O3 suspension with 1 wt.% GNP, prepared via a proprietary process, were sprayed by a SHVOF thermal spray onto 304 stainless steel substrates. The microstructure of Cr2O3 and Cr2O3 + GNP coatings was analyzed using SEM and XRD alongside microhardness, fracture toughness and porosity investigations. Dry sliding wear performance was investigated using a ball on flat tribometer against an alpha alumina ball at loads of 16, 30 and 47 N. The GNP containing coating exhibited improved mechanical properties, however its response to sliding wear was very similar to the non-GNP coating.
Direct Spraying of Fine Ceramic Particles in Thermal Spray
Authors: Shahien Mohammed , Suzuki Masato , Akedo Kentaro Shinoda Jun 
Published: October 2022

Abstract
Deposition of ceramic coatings by spraying of fine powder particles is a promising solution to obtain uniform microstructure and improved properties, because it is expected to form small splats with reduced residual stress and pore size. Although direct injection of fine particles has many challenges such as poor rheological properties (e.g., low flow ability and agglomeration), and small momentum to inject and impact, it is still attractive and worth to try. From this point of view, we have improved feeding and injection technique of fine powder particles, which enables us to directly spray fine ceramic particles with a newly developed low power dc plasma torch. Preliminary results obtained with this system will be compared with those by other fine powder spray technology such as suspension plasma spray and hybrid aerosol deposition to show similarity and difference when the injection methods of the fine powder particles are different in this paper.
Mechanisms of Structure Formation and Thermo-Physical Properties of Gas Detonation Sprayed Fe-Al Type Coatings
Authors: Senderowski Cezary , Panas Andrzej J. , Fikus Bartosz , Wołczyński Waldemar 
Published: October 2022

Abstract
The paper reports the results of structure examination of intermetallic Fe-Al type coatings obtained by the detonation gun spraying on a C45 plain carbon steel substrate. The structure was analysed with scanning (SEM), transmission (TEM) electron microscopy techniques and electron (SAE) and X-ray diffraction methods as well as quantitative inspection of composition in microareas (EDX). Special attention was paid to the interface between the coating and the substrate analyzing particularly the substructure of the individual grains contained up to 15μm away from the substrate surface layer. The results allowed explaining the formation mechanism of the coating morphology with a contribution of intermetallic phases Fe3Al, FeAl, FeAl2 and Fe2Al5 as well as the ε phase taking into consideration the influence of velocity, temperature and pressure on the powder particles during the D-gun spraying. It was established that the coating produced with the DGS method had sublayer morphology of alternate flattened and partially melted grains with wide range of Al content from 39 up to 63 at.%. Partial melting of the individual powder particles brought about the appearance of the amorphous grains and subsequently columnar crystals of the Fe-Al type phases formed sequentially at the interface area coating and cold substrate surface layer material, which was essential in the mechanism of the Fe- Al coating formation. It was established, that in the area of the polycrystalline dispersive structure formed from the highly plasticized FeAl grains during D-gun spraying, complex oxide films identified as Al2O3-γ formed, serving as specific composite reinforcement in the intermetallic Fe-Al coating. A mechanism of crystallization of partially melted Fe-Al particle containing nominally 63 at.% Al was carried out in the work in an attempt to explain the formation of different sub-layers within the Fe-Al intermetallic coating at the interface 045 steel surface layer.
Pulsed Current and Pulsed Powder Operation of the One-Cathode-One-Anode-Plasma-Generator (OCOAPG)-Part II
Authors: Zimmermann Stephan , Schein Jochen 
Published: October 2022

Abstract
In most small and medium enterprises (SMEs) that conduct plasma spraying, a one-cathode, one-anode plasma generator (OCOAPG) is used due to its cost-effectiveness. To achieve high deposition rates, the highest possible fraction of the injected powder has to be melted and accelerated toward the substrate. A sufficiently long and reproducible residence time in plasma is needed that is adequate in relation to the amount and size of the particles This can be achieved by a long plasma jet with little or no temporal variation in length and temperature. In OCOAPG, an arc is operated between a cathode and a central tubular anode, which causes different instabilities in the effluent plasma jet. Due to the instable interaction between the plasma jet and the carrier gas jet continuously incorporating the powder, fluctuations occur resulting in reduced coating quality. Coating systems with a higher number of electrodes (and hence using several arcs) show higher stability and therefore can provide higher coating quality. However, due to their complexity and cost intensity, the investment hurdle for SMEs usually turns out to be too high. Recently, research steps to improve the plasma spraying process with OCOAPG have been undertaken by using a controllable current source to create a uniform interaction between the particle and the gas jet. As the movement of the anodic arc attachment can be actively controlled by current pulses, the plasma jet can be lengthened and shortened at periodic intervals. Furthermore, by pulsing the particle delivery synchronously to the power modulation, an improved particle penetration and consistent residence times can be achieved. First diagnostic results, including example coatings, are presented and discussed within the paper.
High Temperature Erosion Mechanisms and Erosion Rate of Hard Coatings for Surface Recovery of Heavy-Fuel Engines
Authors: Miranda Javier , Bejarano Lorena , Valarezo Alfredo 
Published: October 2022

Abstract
This study aims at evaluating the erosion resistance at temperature of several hard coatings, including: CrC-NiCr by HVOF, Fe-based alloy by Arc Spray, NiCrBSiFe by powder flame spraying. These coatings are to be used for the recovery of highly eroded walls (above 10 mm thickness) of gray cast iron in the exhaust ducts in heavy-fuel engines. The erosion test consists of erosive particles thrown through a high temperature gas jet, for 5 cycles of 5 minutes, according to ASTM G211-14 (modified). Coated samples are subjected to a fuel gas-torch reaching a front temperature of 450ºC and a back temperature of 90ºC (water cooled), simulating the actual application. The eroded samples are characterized using EDS, and SEM. The results show the erosion rate of each material/system, and their corresponding erosion mechanisms. Thus, the results allows for the selection of an optimum coating for this surface recovery application.
Restoring Body of Valuable Historic Vehicles: An Innovative Approach by the Use of Thermal Spray Techniques
Authors: Chierichetti Andrea , Cerri Walter , Meloni Roberto , Barp Luigino 
Published: October 2022

Abstract
The restoration of a valuable historic vehicle is a complex operation; indeed, the vehicle value is directly connected to the degree of authenticity of the restoration. Corrosion has been observed to reduce the thickness of metal sheets from the original 0.03 in. (0.8 mm) to only 0.015 in. (0.4 mm) or even less. In such cases, traditional restoration methods could lead to further deterioration of the metal body. In this article, the authors describe an innovative thermal spray method for restoring metal sheets to their original thickness. This method permits restoration of the original body, preserving the degree of authenticity of the vehicle. The method has been patented by Ferrari SpA.