bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma-Sprayed Particles : Impact Imaging and Flattening Particle Thermal History
Authors: Cedelle J. , Vardelle M. , Pateyron B. , Fauchais P. , Fukumoto M. , Ohgitani I. 
Published: August 2022

Abstract
In plasma spraying, the individual droplet behavior at impact is the fundamental element to understand the resulting coating microstructure. A new experimental set-up, developed in SPCTS laboratory (Limoges, F) with two fast shutter cameras (exposure time : 100 ns…1ms) allows visualisation at impact of a single particle plasma sprayed with a direct current (d.c) torch. A fast two color pyrometer enables to monitor particle temperature just prior to its impact, its flattening and its thermal history. Working in parallel with a free falling drop experiment, enables to obtain larger (about three orders of magnitude) time and dimension scale (realized in Advanced Joining Process Laboratory, Toyohashi, J). Each technique gives interesting and complementary results thanks to pyrometric signals and images. Results obtained with plasma sprayed particles allow studying the matter ejections generated on impact splashing .while both techniques allow following the flattening splashing. Calculation and comparison of quenching rates for millimetre sized drops on a stainless steel substrate give indications concerning the disk shaped splat formation.
HVOF Coating of Metallic Surfaces: Corrosion and Bending Characteristics of Coating
Authors: Fadhli H.Y. , Hashmi M.S.J. , Yilbas B.S. 
Published: August 2022

Abstract
HVOF coating finds wide applications in power generation industry to protect the hot path components from high temperatures gases. The mechanical properties influence the life span of such components. In the present study, mechanical properties of HVOF spray of Inconel-625 alloy onto stainless steel surface was examined. The three point bending tests are carried out to determine the load and the flexural displacements characteristics of the coated workpieces. The workpieces were subjected to aqueous static corrosion environment before and after the three point bending tests. The surface morphology and elemental composition of the coating after the bending tests are examined using SEM and EDS. It is found that the local corrosion site in the coating result in high stiffness of the coating and the cracks extending along the surface of the coating are resulted due to the shear on the surface of the coating.
Microstructure and Electrochemical Corrosion Behavior of the Zn-Al-Mg Coatings Produced by Cored Wires and High Velocity Arc Spraying
Authors: Xu B. , Zhu Z. , Yan Y.-L. , Ma S. , Chen Y. 
Published: August 2022

Abstract
Cored wires and high velocity arc spraying technique (HVAS) were used to produce high Mg content Zn-Al-Mg alloy coatings on low carbon steel substrates. The microstructures, mechanical properties and electrochemical corrosion behaviors of the Zn-Al-Mg coatings were investigated comparing with Zn and Zn-Al alloy coatings. And the electrochemical corrosion mechanisms of the coatings were discussed. The coatings show a typical aspect of layered thermal sprayed material structure. Chemical analysis of the coating indicated the composition to be Zn-14.9Al-5.9Mg-3.0O (wt.%). The main phases in the coatings are Zn, Mg2Zn11, Al12Mg17 and MgAl2O4, together with a little Al2O3 and ZnO. The Zn-Al-Mg coatings show higher electrochemical corrosion resistance in salt solution than Zn-Al coatings. The corrosion potential of Zn-Al and Zn-Al-Mg coatings decreased a little and then increased towards the noble potential. The analysis of XRD and Electrochemical impedance spectroscopy (EIS) shows that, with addition of Mg, the corrosion products can block off the pores in the Zn-Al-Mg coating, which is so-called self sealing, and thus prevent attack on the underlying steel substrate.
Adhesion Tests for Thermal Spray Coatings: Application Range of Tensile, Shear and Interfacial Indentation Methods
Authors: Hadad M. , Marot G. , Démarécaux Ph. , Lesage J. , Michler J. , Siegmann S. 
Published: August 2022

Abstract
Three adhesion measurement methods for thermal spray coatings, namely tensile adhesive strength (according to EN 582), interfacial indentation and in-plane tensile tests were investigated in terms of accuracy of the results and application potential for different coating / substrate conditions. Whereas the tensile adhesive strength test is widely used in industry, the other two methods are still under development in research laboratories and therefore only few experimental data on the accuracy of the methods and on the potential in an industrial context are available. For that reason, dissimilar coating-substrate combinations covering a wide range of types of thermal spray coating-substrate systems were tested using all these methods. Ceramic (Al2O3) and metallic (NiCr 80-20) coatings were thermally sprayed by flame spraying with two different thickness on titanium alloy and steel substrates exhibiting each two distinct roughness levels. The distinguished coating properties include the coating toughness, shear strength, interfacial toughness, and adhesive strength. Thermally sprayed coatings do not only show an interfacial complexity, but also the integrity of the interface of substrate and coating has to be considered, as well as porosity, cracks and residual stresses. In this paper, each measurement method was found to be related to certain type of loading conditions and fracture mode. The results of the different methods are compared and the limits of applicability of the different methods are discussed.
Properties of Composite Coatings Sprayed by the Low Temperature High Velocity Air Fuel Spray
Authors: Wang H. , Yuan X. , Hou G. , Zha B. 
Published: August 2022

Abstract
Based on the HVO-AF (High Velocity Oxygen-Air Fuel) thermal spray system, the Low Temperature High Velocity Air Fuel Spray was realized by additional liquid feed stocks. In this paper, the microstructure and characteristics of composite coatings sprayed by this spray technology were analyzed. Composite powders were composed at three mass fractions, Fe, 5mass%Fe -polymer, 15mass%Fe-polymer. In the experiments, the coatings properties were tested. The results indicated that all the coatings microstructure is dense and low porosity; metal particles were dispersed with polymer in the coatings. There were little oxide phase in the coatings. The coatings were closely combined with substrate, the reflectance coefficient of 5mass%Fe-polymer composite coatings is better than others, the reflectance coefficient curve of the coatings is 2~6dB at 2~18GHz.
Characterization of the Porosity of a TBC Sprayed by a High Power Plasma System for SOFC Application
Authors: Goubot N. , Dhers J. , Gallet D. , Thery A. 
Published: August 2022

Abstract
The purpose of this work is a general assessment of the evolution of the porosity of a thermal barrier coating (PSZ : Partially Stabilized Zirconia with 7% wt yttria) used as an SOFC electrolyte sprayed by a High Power Plasma system Plazjet using commercial powders. The properties of these coatings are investigated using a microstructural and a physical approach. The different steps concern : - the optimisation of the spraying parameters of the Plazjet gun, in order to obtain either very dense, or porous top coat microstructure. We focused on parameters such as the gun (external, or step) or the morphology of the powder. The use of a strict methodology to analyze the results. Characteristics obtained by various measures, qualitative and quantitative, are compared and discussed.
Comparative Study on Segmented Thermal Barrier Coatings Sprayed from Different Feedstocks
Authors: Guo H.B. , Kuroda S. , Murakami H. 
Published: August 2022

Abstract
Type of powder feedstock greatly affects properties of zirconia coatings since they interact differently in a plasma flame and hence influence microstructure development. In this study, ZrO2-8wt% Y2O3 thermal barrier coatings (TBCs) have been produced by atmospheric plasma spraying fused and crushed (FC) and hollow sphere (HOSP) feedstock powders. The sprayed coatings contained segmentation cracks going through the coating thickness. High substrate temperature during spraying gave rise to increased segmentation crack density (Ds). The FC powder has the capability of providing coatings with high segmentation crack density compared with the HOSP one. At lower temperature, the HOSP coating was more porous than the FC coating sprayed at similar temperature and hence exhibited a much reduced thermal diffusivity. At high plasma temperature, the HOSP particles attained higher particle surface temperatures and velocities than the FC ones. The particles temperatures and velocities for the HOSP particles were influenced more significantly by spray condition than those for FC particles.
Study of CVD Overaluminising on Different CoNiCrAlY Bond Coats Deposited by High Velocity Oxygen Fuel (HVOF), Low Pressure Plasma Spray (LPPS) and Vacuum Plasma Spray (VPS)
Authors: Scrivani A. , Rizzi G. , Stanic V. 
Published: August 2022

Abstract
Coating technology is progressing at a steady rate with continuous significant improvements in the coatings performance. In the aerospace field, as well as in the stationary gas turbine field, coatings deposited by different processes (thermal spray, CVD, EBPVD) play an important role in order to increase the performances of the engines. In particular, in order to improve the resistance to oxidation and corrosion at high temperature, aluminium is deposited by several techniques (pack aluminising, above the pack and CVD) in alternative or addition to thermal spray coatings (mainly MCrAlY alloys where M stands for Co, Ni or CoNi). These MCrAlY coatings are generally deposited by Low Pressure Plasma Spray (LPPS) or Vacuum Plasma Spray (VPS), but also by High Velocity Oxygen Fuel (HVOF) and Air Plasma Spray (APS). This paper addresses the study of aluminium coatings deposited by CVD on CoNiCrAlY bond coats deposited by different processes: VPS with F4 gun, LPPS with EPI gun and HVOF. The aim is to verify if and how the different CoNiCrAlY coatings obtained by these three processes with different content of oxides and porosity could affect the deposition rate and quality of the Al coatings. The obtained samples have been characterized from the metallographic point of view in order to determine porosity, thickness and structure of both CoNiCrAlY and Al coatings. Al coating thickness has been taken as parameter in order to define the Al coating deposition rate on the three different CoNiCrAlY coatings. Further tests for the determination of aluminium content and chemical composition of the coatings are in progress.
HVOF Spraying of WC-Co Coatings with Liquid-Fuelled and Gas-Fuelled Systems: Competing Mechanisms of Structural Degradation
Authors: Shipway P.H. , McCartney D.G. , Sudaprasert T. 
Published: August 2022

Abstract
It is widely known that during high velocity oxy-fuel (HVOF) spraying of tungsten carbide – cobalt (WC-Co) coatings, decomposition occurs resulting in the formation of W2C and a relatively brittle amorphous binder phase (along with other carbides and even metallic tungsten). Decomposition has generally been seen to be deleterious to the wear resistance of these coatings and, as such, there have been moves to reduce it. Since decomposition during spraying initiates with WC dissolution into the molten binder phase, strategies for its minimization have been based on reduction of particle temperatures and exposure times during spraying. Moves in spraying from gas-fuelled systems to liquid-fuelled systems have contributed towards these goals. This paper examines microstructural features and wear behaviour of WC-Co coatings deposited with both a liquid-fuelled and a gas-fuelled system. Contrary to expectation, it was found that the wear rate of the liquid-fuel sprayed coating was five to ten times higher than that of the gas-fuel sprayed coating. It was shown that whilst the degree of decomposition was limited during spraying with a liquid-fuelled system, the solid core of WC-Co suffers significant mechanical damage on impact as it is deposited, resulting in carbide fracture and size reduction and thus to the low observed wear resistance.
Oxidation of HVOF-Sprayed Hardmetal Coatings
Authors: Berger L.-M. , Zieris R. , Saaro S. 
Published: August 2022

Abstract
In the current study, the oxidation of hardmetal coatings (WC-12%Co, WC-17%Co, WC-10%Co4%Cr, WC-20%“CrC”-7%Ni, Cr3C2-25%NiCr, (Ti,Mo)(C,N)-29%Ni and (Ti,Mo)(C,N)-29%Co) in the temperature range 350- 900°C was studied for test durations ranging from 2 h to 128 h. The formation of oxide scales was investigated by X-ray diffraction, as well as by optical microscopy and SEM (including EDX) of coating cross sections. For coatings obtained by spraying with DJH 2700 and TopGun HVOF systems, the phase composition had only a moderate influence on high-temperature oxidation behavior in atmospheric conditions. The first oxides detectable by X-ray diffraction appeared on the coating surfaces after oxidation at 350°C for 128 h for all coatings. Pronounced oxidation (formation of oxide scales with thicknesses of greater than 10 µm) started at 600°C. Oxide scale growth differed significantly above this temperature among the hardmetal compositions studied here. WC-20%"CrC"-7%Ni and Cr3C2-NiCr had the highest oxidation resistance, with the oxide scale thicknesses lying below 10 ìm after oxidation at 800°C and 900°C for the two materials, respectively.
Influence of Spraying Parameters on the Properties of HVOF Alumina Coatings
Authors: Riley M.A. , Sturgeon A.J. 
Published: August 2022

Abstract
The HVOF spraying process has recently been considered for the deposition of dense alumina coatings for dielectric coatings in semiconductor applications and as a turbine blade tip coating in aeroengines. However, due to the lower flame temperature of the HVOF process compared to the plasma spray process it is necessary to have good control over the key process parameters to achieve the correct coating characteristics. The work reported presents the results of a design of experiment study carried out on a TopGun HVOF system used to prepare coatings of alumina. The influence of several key parameters on coating characteristics such as porosity, alumina phase type, microhardness, surface roughness and adhesion have been determined. The parameters varied included oxygen and hydrogen fuel gas flow rates, and spray distance. Based on the results of these investigations recommendations are made on the control of key parameters and the range of coating characteristics that can be expected.
Relationship between Surface Topography Parameters and Adhesion Strength for Plasma Spraying
Authors: Bahbou F. , Nylén P. 
Published: August 2022

Abstract
To achieve sufficient adhesion strength within thermal spraying, the surface to be coated has to be modified. Grit blasting is the most common way to generate a clean and roughened surface. The bonding mechanism between the grit-blasted substrate and the coating is assumed to be due to mechanical anchoring, why an optimal surface roughness is essential. The surface roughness is usually evaluated using Ra which cannot fully characterize the complex nature of the chaotic substrate topography. This study was performed in order to evaluate if Ra can be replaced by other surface characteristic parameters such us RΔq, Rpk, Rpv, Rk…with higher correlation to adhesion strength. Average roughness was measured by a perthometer and with white light interferometry to get 3D images of the surface topography. Disc shaped substrate samples of Ti6Al4V (AMS 4928) were grit blasted with aluminium oxide grit and plasma sprayed with a Ni5%Al coating. Adhesion strength was determined according to the ASTM C633 standard. The correlation between a number of different surface-parameters and adhesion strength were evaluated and compared with Ra.
New Technique of Laser Cladding with Tungsten Carbide and Diamond
Authors: Machi F. , Dezert D. , Maybom H. , Desmette S. , Lamiene E. , Bauninger G. , Nicholson C. , Cerny E. , Magnee A. , Zenati R. , Fantozzi G. 
Published: August 2022

Abstract
Wear resistance of materials in very aggressive environment of different industrial sectors like drilling, mining, cutting, etc, appears to be critical and many efforts have been made to limit the major economic loss that represents a broken or damaged tool. The objective of the CLADIAM project (G5ST-CT-2002-50179) is to develop a cladding technique to coat complex parts based on an innovative cladding material composed of diamond pellets and cast spherical tungsten carbide particles using an automated high power diode laser (HPLD) equipment. The result of these two and a half years of work has led to the finalization of following techniques: A pelletizing alloy that takes into account the constraints of laser cladding, Enrobing of diamond particles to avoid their damage, An industrial technique, technically and economically efficient, of laser cladding that allows the realization of complex shapes. The combination of a new technique of wear and abrasion tests has led to the characterization of the obtained cladding. The results have been compared with the tests on industrial parts in severe and even extreme wear conditions. The development of this new cladding technology has been possible thanks to the use, the characterization and the optimization of specific cladding nozzles associated with the special beam of high power diode laser. The results obtained are very encouraging and open the doors to new claddings that combine the specific advantages of diamond and tungsten carbides for the nature of cladding, but also the fineness of the structure, the improvement of behaviour in wear conditions, the small thermal impact of the parts, some of the well known advantages of laser cladding.
The Effects of Deposition Parameters and Gaseous Detonation Equipment Design on the Coating Formation
Authors: Kharlamov Y. , Chattha J.A. , Kharlamov M. 
Published: August 2022

Abstract
By use of up-to-date methods of gaseous detonation spraying it is possible to obtain coatings with wide range of thermal and kinetic energy of sprayed particles and their state (liquid, solid, semiliquid, with change of their chemical and phase composition duration of stay in impulse hot gaseous detonation jet, etc.). The philosophy of gas detonation sprayed coating structure and properties control include next basic methods: (1) change of values and ratio of thermal and kinetic energy of sprayed particles; (2) governing of thickness and sizes of single layers of coating (“coating spot“), D-Gun rate of fire, and relative velocity of moving of D-Gun and workpart; (3) change of dispersion and shape of powder particles; (4) regulation of thermal cycle of coating in process of spraying by use preliminary, concomitant or post spraying heating or cooling; (5) use of variable spraying modes for obtaining of individual layers and zones of coating (change of composition and flow rate of gases and powder, D-Gun fire rate, powder dispersion, distance of spraying, etc.); (6) settlement of ratio between percentage of amorphous, microcrystalline and crystalline phases, metastable and equilibrium phases by selection of rational conditions of spraying; (7) control of degree of physico-chemical transformations into powder particles (polymorphic transformations, dissociation, oxidation, interaction between components of composite powders, etc.), change of time of particles stay into gas products flow, composition and parameters of gaseous medium, etc.; (8) alloying of sprayed powders as for assurance of necessary properties of coatings as for improvement of their inclination to coating formation (oxidation resistance into high temperature gas flow, inclination of seizure, etc.); (9) use of composite powders; (10) spraying at mode with powder particles which have premelting temperature at time of coating formation; (11) treatment of sprayed coatings (thermal, thermo-chemical, thermo-mechanical, etc.); (12) control of coating macrostructure by successive deposition of layers, bands and spots of coatings with smooth or abrupt change of composition, deposition of discrete coatings; etc. Abstract only; no full-text paper available.
Construction and Analysis of Ozone Condensation System for Oxide Superconductor Thin Film
Authors: Cheon M.-W. , Park Y.-P. 
Published: August 2022

Abstract
An ozone condensation system is evaluated from the viewpoint of an ozone supplier for oxide thin film growth. Ozone is condensed by the adsorption method and its concentration is analyzed using the thermal decomposition method. The concentration of ozone exceeds 90 mol% and ozone is supplied for a sufficiently long time to grow oxide thin films. Investigation of the ozone decomposition rate demonstrates that ozone can be transferred into the film growth chamber without marked decomposition. The ozone concentration is also evaluated using a quadrupole mass analyzer and the accuracy of this method is compared with the results of the thermal decomposition method.
Oxidation Behavior of In-Flight Molten Aluminum Droplets in the Twin-Wire Electric Arc Thermal Spray Process
Authors: Guillen D. , Williams B.G. 
Published: August 2022

Abstract
This paper examines the in-flight oxidation of molten aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. The oxidation reaction of aluminum in air is highly exothermic and is represented by a heat generation term in the energy balance. Aerodynamic shear at the droplet surface: (1) enhances the amount of in-flight oxidation by promoting entrainment and mixing of the surface oxides within the droplet, and (2) causes a continuous heat generation effect due to the exothermic oxidation reaction that sustains droplet temperature as compared to a droplet without internal circulation. This continual source of heat input keeps the droplets in a liquid state during flight. A linear rate law based on the Mott-Cabrera theory was used to estimate the growth of the surface oxide layer formed during droplet flight. An explanation is provided for the elevated, nearly constant surface temperature (~ 2000 °C) of the droplets during flight to the substrate and it is shown that the majority of oxide content in the coating is produced during flight, rather than after deposition. The calculated oxide volume fraction of an average droplet at impact agrees well with the experimentally determined oxide content for a typical TWEA-sprayed aluminum coating, which ranges from 3.3 to 12.7%.
Corrosion Properties of Plasma-Sprayed Coatings using Oxide Powders
Authors: Song Y. , Ahn J. , Kim B-Y. , Lee D. , Nam K. , Lee K-H. 
Published: August 2022

Abstract
Three different oxides of CrO2-TiO2, Al2O3 and Al2O3-TiO2 were plasma-sprayed on Ti substrate to evaluate the crystal structure and the corrosion properties of the coatings. No phase change of the coatings after corrosion test in 0.5 M H2SO4 solution at 25°C was found regardless of the presence of the NiCoCrAlY bond layer. Electrochemical measurements and SEM results revealed that the single coatings without the bond layer were always effective against corrosion resistance due to lower current density within the passive region. Pitting corrosion of the surface was observed for the Al2O3 coating. It can be concluded that the Al2O3-TiO2 coating without the bond layer may be the best oxide among the oxides investigated due to low porosity (5.4%), smooth surface roughness (4.5 m), low current density (6.3×10-8 A/cm2) in the passive region, low corrosion potential (Ecorr, -0.55 V) and no pitting corrosion.