bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructures and Tribological Performances of Cold Sprayed Tin-Bronze Based Composite Coatings
Authors: Guo X. , Zhang G. , Liao H. , Coddet C. , Li W. , Gao Y. 
Published: September 2022

Abstract
In this paper, tin-bronze/TiN and tin-bronze/quasicrystal (AlCuFeB) composite coatings were fabricated by cold spray process. Microstructures and microhardness of coatings were characterized. Ball-on-disc dry sliding wear tests were conducted in an ambient condition to examine the tribological performance of the composite coatings. The results show that the microhardness and densities of composite coatings increase significantly compared to those of the pure tin-bronze coating. The friction coefficients of coatings decrease with the introduction of reinforces. Furthermore, the tin-bronze/quasicrystal composite coating yields a lower friction coefficient and wear rate compared to the bronze/TiN coating. The tribological mechanisms were discussed.
Al-12Si Cold Sprayed Coatings with Controlled Porosity
Authors: Christoulis D.K. , Borit F. , Guipont V. , Jeandin M. 
Published: September 2022

Abstract
The demand of industry for metallic thermal sprayed coatings with controlled porosity until now is fulfilled by the spraying of metallic powders mixed with additives (organic element in many cases) which play the role of pores. The new technology of cold spray can lead to the formation of innovate coatings of controlled porosity by using pure metallic (or alloy) powder without any further addition. A fine Al-12Si powder (&lt;45 µm) was sprayed with a cold spray system (CGT Kinetic 3000-M) on stainless steel substrate under different spraying conditions. In the present study, the new polymeric nozzle PBI-33 of CGT was used for the formation of al-based coatings. The microstructure, the porosity, the Vickers microhardness and the superficial Rockwell hardness (R15Y) of the produced coatings are examined.
Development of a Low Cost System for the Cold Spray Process with Helium
Authors: Verdy C. , Liao H. , Landemarre O. , Coddet C. 
Published: September 2022

Abstract
The use of helium with the cold spray process is well-known to give a higher velocity to the particles and thus denser coatings than those obtained with the classical use of nitrogen. The LERMPS-UTBM laboratory has developed a unique system to use helium without losses. The spray process occurs in a LPPS tank and a specific closed circuit including the cooling and filtering of helium allows its circulation. The spray operations can be made at low helium pressure with no pollution by oxygen. The control device allows to work with different pressures and gas temperatures at the torch with the same tank pressure. Helium gas flow can reach 180 Nm3/h and current cold spray torches could be used. The circulation and reuse of helium in a closed circuit result in a very low consumption of helium. The first coatings of copper alloys are presented in this work.
Flame Sprayed Al-12Si Coatings for the Improvement of the Adhesion of Composite Casting Profiles
Authors: Voyer J. , Peterlechner C. , Noster U. 
Published: September 2022

Abstract
Flame sprayed Al-12Si coatings were produced onto the surface of composite castings parts in order to enhance the adhesion of such castings. Due to the high surface roughness and the presence of pores in the coatings combined with the formation of an intermetallic phase at the interface, the adhesion of flame sprayed composite castings could be enhanced by a factor of 2 in comparison to blank castings and by a factor of 1.3 when compared to sand-blasted castings. However, results also show that gaps are mostly present at the interface between the Al profiles and the flame sprayed coatings and these gaps have a negative effect on the adhesion values of the composite casting parts. Therefore, an optimization of the adhesion of the coating on the Al profiles through an optimization of both the sand-blasting and the flame spraying parameters would be beneficial for further enhancement of the adhesion of composite casting parts.
Thermal Fluxes Transferred by HVOF Jets Produced by Different Guns
Authors: Bolot R. , Landemarre O. , Coddet C. 
Published: September 2022

Abstract
Thermal fluxes transferred during HVOF thermal spray have an important influence on the thermal history of the work-piece. Thus, there is an interest in quantifying these fluxes. Today, different studies based on the use of calorimeters were proposed in the literature and CFD calculations may also be used to confirm the measures. In the present study, a new method based on the measurement of the transient increase of the work-piece temperature was used in order to estimate the thermal exchanges between an HVOF jet impinging on different diameter cylinders. The results indicate that fluxes of several MW/m2 may be transferred depending on the standoff distance, spray parameters and gun.
Influence of Particle Velocity on Splat Formation during Thermal Spraying
Authors: Kharlamov Y.A. 
Published: September 2022

Abstract
Current understanding of mechanisms of splat formation during thermal spraying are discussed. Schematic of influence of particle velocity on change of impact and forward pressure during particle-substrate interaction are given. The existence of three typical zones of particle-substrate contact is shown. These zones are: (1) central circle type mechanically activated by hammer and head pressure; (2) middle ring-shaped mechanically activated by head pressure and friction of spreading particle; (3) peripheral ring-shaped mechanically activated by friction of spreading particle. It is possible to estimate dimensions of these zones analytically. The stress distribution on particle-substrate contact during splat formation is discussed. It is shown that relative values of area for these zones depends from particle velocity. The presence of these typical zones during splat formation shown by conduction of special model experiments.
Investigation of a Novel Plasma Sprayed YSZ Ceramic Coating Deposited by Amorphous YSZ Ceramic Powder Feedstock
Authors: Lin F. , Yang Z.Y. , Li X.F. , Yan S.K. , Liu J.H. , Zhang J.H. , Wang L.M. 
Published: September 2022

Abstract
An amorphous Yttria Stabilized Zirconia (YSZ) ceramic powder feedstock is successfully used to produce a novel YSZ ceramic coating by plasma spraying process, in this paper. Unlike conventional atmosphere plasma spray (APS) and solution precursor plasma spray (SPPS) YSZ coatings, the YSZ ceramic coating fabricated by plasma spraying amorphous YSZ ceramic powder feedstock reveals complex structure of cell and ultrafine particles instead of conventional splats and porous structure. A large number of ultrafine particles are found in the cell. Phase structure of the YSZ ceramic coating is tetragonal. Porosity is about 31%. In addition, thermal cycling test is nearly 370 cycles, and the thermal conductivity is 1.0 W.m-1.K-1, at 1250 temperature. Based on these excellent properties, the YSZ ceramic coating fabricated by plasma spraying amorphous YSZ ceramic powder feedstock should be used as high-temperature abradable sealing coatings and thermal barrier coatings (TBCs).
Experimental Simulation Study of Intersplat Bonding Formation by Deposition of YSZ Splats on Preheated YSZ Substrate
Authors: Li C.-J. , Xing Y.-Z. , Li Y. , Li C.-X. , Yang G.-J. 
Published: September 2022

Abstract
Yttria stabilized zirconia (YSZ) splats were plasma sprayed on the YSZ substrate preheated to different temperature to examine the influence of the temperature of the underlying surface on which molten droplet impacts on deposition characteristics. The splat morphology and the bonding at the splat-substrate interfaces were examined by SEM. It was found that the crack density decreases rapidly with the increase of the temperature when the splat were formed on an YSZ substrate preheated to above 800°C. The nucleation of YSZ melt on the base of YSZ substrate grains takes place during solidification leading to the formation of the bonding between the splat and substrate when the temperature is increased to over 600°C. The substantial bonding was observed at the interface between YSZ splat and YSZ substrate as the temperature is increased to over 800°C. The results revealed that the temperature of the previous splat on which a molten droplet impacts significantly influence the formation of the interface bonding. In addition, the mechanism and condition for the bonding formation of a splat on a substrate with the identical compositions were discussed.
Influence of Plasma Generation Conditions in Gas-Water Torch on Spraying Process
Authors: Kavka T. , Maslani A. , Kopecky V. , Sember V. , Chumak O. , Hrabovsky M. 
Published: September 2022

Abstract
The present paper examines a hybrid DC arc thermal plasma torch with gas-water stabilisation and its application for thermal spraying. The torch was worked out based on the water-stabilised plasma torch WSP, main features of which are high temperature of the generated plasma and high powder through-put. In the hybrid torch the cathode part is modified in the way like in gas torches, which not only provides proper stabilisation of the arc in this region and cathode protection from contact with stabilising water but also allows to vary properties of the generated plasma. Change of the secondary gas flow rate, which is usually argon, results in strong changes of the plasma gas density, while the energy balance of the torch remains almost unchanged. This in turn leads to modification of the plasma jet properties. The paper describes effect of the plasma torch parameters on behaviour of the generated plasma jet and injected powder particles. The results show how particle velocities follow changes of the plasma jet properties according to the plasma torch operation parameters. Both increase of arc current and argon flow rate provided increase of particle velocities.
Fundamental Understanding of the Liquid Precursor Plasma Spray Process Through Modeling and Experiments
Authors: Jordan E.H. , Cetegen B.M. , Gell M. , Chen D. , Basu S. , Teicholz M. , Ma X. 
Published: September 2022

Abstract
Abstract-Solution precursor plasma spray (SPPS) is a relatively new thermal spray process in which chemical precursors are injected into DC-arc plasma spray torch in place of powder. This process is able to make relatively porous (15-25% porosity) thermal barrier coatings with through-thickness cracks that enhance their thermal strain resistance. The SPPS process can also make dense titania and alumina zirconia coatings. The process can make thin and thick coatings, dense and porous coatings, structural and functional preforms, new compositions, and metastable materials. Metastable materials arise because the solution is molecularly mixed and the cooling rate in thermal spray is high. The process has the disadvantage of needing to provide energy to evaporate the solvent and of being a new process where less extensive empirical knowledge and modeling insights exist, compared to air plasma spray with powders. The microstructure process parameter relation is explored. Results from modeling studies concerning evaporation of droplets and related solute concentration gradients, modeling studies of aerodynamic break-up and experimental studies of non-aero-based droplet break-up and of the effects of solution concentration will be described. These studies will be related to experimental results for making dense coatings.
Effects of Heat Treatment on Properties of Plasma Spray NiAl Coatings
Authors: Moshref Javadi M. , Edris H. , Salehi M. 
Published: September 2022

Abstract
For production of intermetallic coatings, various types of Ni-Al powders were plasma sprayed at different spray distance and the effect of heat treatment on phases, microstructures and microhardness of coatings was examined. XRD, SEM, EDAX and microhardness were used for characterization of the coatings. Heat treatment of the coatings in various temperatures caused changes in hardness of the coating, increased percentage of intermetallic compounds, completed intermetallic production reactions, but did not change porosity percent. Increasing heat treatment temperature caused oxidation and decreased improvement of coating properties.
Mathematical Model of Surface Plasma Hardening Process of Steel Parts
Authors: Markovnik D. , Kundas S. , Ivanov D. 
Published: September 2022

Abstract
The plasma surface hardening, as one of methods of surface treatment by heating sources with high power density, finds presently wide and effective application in conditions of short-series and single-part (including repair), and large-scale and wholesale manufacture. One of effective methods for research and optimization of the plasma surface hardening is the use of computer simulation. The complex mathematical model of steel parts hardening at high-speed plasma heating is presented in the article. Model includes mathematical description of steel parts heating and cooling, and also forming of their stress-strain state. The distinctive feature of the presented model is taking into account under modeling of phase transformations and plastic deformations. It allows to achieve the maximally adaptation of the simulation results to real physical characteristics of the process. The algorithm of model computer realization, based on the application of final elements method is offered.
An Effect of Low Pressure Gas Dynamic Spray on Micro-Corrosion Behavior of Al Alloys
Authors: Leshchynsky V. , Maeva E. , Lubrick M. , Villafuerte J. , Maev R. 
Published: September 2022

Abstract
The corrosion behavior of Al alloys, produced by cast and powder (Low Pressure Gas Dynamic Spray or Cold Spray) technologies, was examined in 3% sodium chloride solution from the viewpoint of localized corrosion. The susceptibility to localized corrosion is known to be strongly affected by intermetallic phases present in the alloy’s microstructure. The influence of individual cathodic and anodic intermetallic phases was investigated by using a microelectrochemical setup and by electrochemical methods. The optical and scanning electron microscopy data reveal that the cast and powdered alloys experience localized corrosion due to presence of the intermetallic phases which results in the micro-corrosion effects such as exfoliation corrosion, intergranular or crevice corrosion, and most severely pitting. Cast material has lower corrosion properties because of the higher heterogeneity of the structure as compared with powder sprayed composite.
Effect of Zinc and Aluminium Thermal Spray Coatings on Hydrogen Embrittlement in Marine Industry
Authors: Moshref Javadi M. 
Published: September 2022

Abstract
Hydrogen embrittlement in high strength marine structural steels can occur by improper cathodic protection. In this article the possibility of Hydrogen embrittlement (HE) in high strength steels caused by zinc and aluminium thermal sprayed (TS) coatings has been considered. Provided potential from the TS coatings in marine environments and permissible potential for performing cathodic protection and inhibiting HE has been described. Also effective parameters on HE and prevention methods for HE by thermal sprayed coatings has been reviewed. An effective method for quality stabilizing and potential regulating in anticorrosion TS coatings is utilization of the alloyed materials. Most used material for anticorrosion TS coatings is aluminium that provides relatively moderate potential and low current density and in particular situation can cause HE.
Tribological Behaviour of Thermally Sprayed Coatings at Elevated Temperatures
Authors: Houdková Š. , Zahálka F. , Kašparová M. , Berger L.-M. 
Published: September 2022

Abstract
Hardmetal coatings prepared by high-velocity oxy-fuel (HVOF) spraying represent an advanced solution for surface protection against wear. The work presented in this paper focussed on the comparison of the tribological behaviour of WC-Co, Cr3C2-NiCr and (Ti,Mo)(C,N)-NiCo hardmetal coatings under dry sliding wear conditions at room and elevated temperatures (at 500°C and 700°C). The friction properties of these HVOF-sprayed coatings were studied in detail. The progression of the coefficient of friction (CoF) was measured during the pin-on-disc tests at the different temperatures. The mechanisms of wear and the heat-related changes in surface roughness and microhardness of the coatings were studied.
Comparing Study of High Temperature Erosion of HVOF Sprayed Cr3C2-NiCr Coating and Mild Steel for Boiler Tube
Authors: Yang G. , Zhang S. , Wang Y. , Li C. , Li C. 
Published: September 2022

Abstract
The significant erosion of the boiler tube at high temperature becomes an important problem for the safe operation of circulating fluidized bed boiler. This paper investigated the erosion behavior of the HVOF sprayed Cr3C2-NiCr coating at high temperature comparing with the typical mild steel for boiler tube. Results showed that the erosion rate of the mild steel increased with the increase of temperature. The erosion rate of the mild steel at 800°C was 4 times that at 300°C at an erosion angle of 30°. However, the erosion rate of the HVOF sprayed Cr3C2-NiCr coating was not influenced by the temperature in the range of 300 to 800°C. It is found that the erosion resistance of HVOF sprayed Cr3C2-NiCr coating was more than 3 time higher than that of the mild steel at 700 to 800°C. In addition to the ploughing on the surface of the worn coating, the cracking along splats interfaces in the coating was clearly observed on the cross-sectional microstructure of the coating. The results indicate that the erosion performance of the HVOF sprayed Cr3C2-NiCr coating is controlled by the cohesion between splats in the coating and can be further enhanced by improving splat cohesion.
Comparisons of Microstructure and Properties of Three Cobalt-Based Cermets Deposited by High Velocity Oxy-Fuel Spraying using Clad Powders
Authors: Wang Y.-Y. , Li C.-J. , Yang G.-J. , Li C.-X. 
Published: September 2022

Abstract
Three types of cobalt-based cermet coatings were prepared by high velocity oxy-fuel (HVOF) spraying using cobalt- clad TiC-50Co, SiC-50 Co and WC-18Co powders. The microstructure of three coatings was characterized using a scanning electron microscope (SEM). The adhesive strength of the coatings was tested according ASTM C633-79 standard. The hardness of three coatings was measured using a HV-5 Vickers hardness tester. The abrasive wear performance of the coatings was examined by a dry-sand rubber wheel tester according to ASTM G65-61 standard. The results show that the density, thermo physical properties and volume fractions of the solid carbide phases in the spray particle have a significant influence on the adhesive strength of the coatings. The hardness of WC-18Co coating is higher than that of TiC-50Co and SiC-50 coatings and is much lower than WC-17Co coating deposited with sintered-crushed powders. Moreover, the abrasive wear volume loss of the WC-18Co coating is about 60 times higher than that of the WC-12Co coating sprayed by sintered-crushed powder, and greatly lower than that of TiC-50Co and SiC-50 coatings. The wear mechanisms of three coatings are discussed.
Improvement of the Corrosion Resistance of Magnesium Alloys by Means of Coating and Remelting
Authors: Wielage B. , Lampke Th. , Pokhmurska H. 
Published: September 2022

Abstract
The implementation of magnesium alloys for automotive, aeronautic and other applications is of the great importance due to their especial properties. Magnesium offers greater weight saving capacity than aluminium, as its density, 1.7 g/cm-3, is two thirds the density of aluminium, 2.7 g/cm-3, without significant loss of strength and magnesium alloys show high specific strength. On the other hand surface properties of magnesium alloys like wear and corrosion resistance are rather poor. A large amount of methods are intensively elaborated to overcome this problem from developing of new alloys, different surface treatment methods and a great variety of coating systems. In present work the results concerning improvement of corrosion and wear resistance of magnesium alloys by means of zinc based coatings are presented. Coatings are deposited on magnesium substrates (AM20, AZ31, AZ91) by arc spraying with Zn, ZnAl4 and ZnAl15 solid wires as well as by electroplating of zinc. Nevertheless the onset of bimetallic corrosion between Zn and Mg significantly increases corrosion current density. In order to provide longer protection, two main technological solutions are taken into consideration. First relies upon a modification of the main electroplating technology, second is based on the selection of an effective post treatment. For the first approach a consecutive process is elaborated based on the two-step electrodeposition. The first is from alkaline bath followed by the second step in acidic chloride bath. A dense and compact complex layer is obtained. The second approach is based on the post treatment of deposited coatings and provides a formation of thick and uniform reaction layer in magnesium on the interface between zinc or zinc based coating and substrate. These layers have fine eutectic structure with microhardness 3-4 times higher than that of the base material. Heat treatment is carried out with focused irradiation of tungsten halogen lamp line heater in atmosphere. Microstructure of deposited coatings as well as that of modified surface layers is investigated by metallographic methods. Corrosion properties are estimated by electrochemical measurements. Abrasion wear resistance of the modified layers is determined by scratch test and oscillating wear tests. It is shown that the both applied methods improve corrosion properties of magnesium alloys. Electrolytic zinc coatings deposited by electroplating in the elaborated two- step process demonstrate good barrier properties. Durability increases about three times in comparison with a single coat obtained from alkaline bath. Infra red heat treatment of thermal spray coatings results in formation of modified layers in magnesium substrates that prevent the galvanic corrosion of investigated systems. Wear resistance of reaction layers is up to 4 times higher to compare with the base material.
Diffusion Barrier Coatings for CFC Components by Plasma Spraying – Some Research Results of the Project "IGF 14.880 N"
Authors: Bobzin K. , Zhao L. , Ernst F. , Richardt K. 
Published: September 2022

Abstract
Carbon fibre reinforced carbon (CFC) composites have been more and more used in different industrial areas as high temperature materials. Some application examples are CFC components in modern furnaces for heat-treatment and brazing. Because CFC components can react with metallic materials when they contact each other, diffusion barrier coatings are essentially important for such CFC components. The aim of the project IGF 14.880 N “Thermally sprayed diffusion barrier coatings for CFC components in high temperature applications” is to develop diffusion barrier coatings by thermal spraying technology. In the project, different coating systems have been developed and investigated regarding the coating build-up, coating microstructure, bonding, thermal shock resistance and diffusion barrier function. The research results reveal that some developed coating systems are suitable for applications in furnaces. In the present paper, some research results of this project are reported.