bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Powder Composition on the Microstructure and Wear Properties of Sprayed Cast Iron Coatings
Authors: Morks M.F. , Shoeib M.A. , Tsunekawa Y. , Okumiya M. 
Published: September 2022

Abstract
Microstructure and properties of plasma sprayed cast iron coatings are closely linked to the spray conditions such as substrate temperature, chamber pressure, particle size, and spray distance. Another factor is the chemical composition of sprayed particles, which affects the physical properties such as density, viscosity, and thermal conductivity of droplets. In spraying cast iron on aluminum alloy substrate the purpose is to deposit a superior wear resistant coating as an approach to improve its wear resistance. Presence of graphite in cast iron increases the wear resistance of cast iron coating because of its self-lubricant property. Graphite grows during droplet solidification and splat cooling and thus its appearance is related to the solidification rate of the individual droplets. Alloying elements such as Al and Si in cast iron materials promote the graphite formation because they act as strong graphitizers probably by creation active nuclei for graphite growing. The aim of this paper is to examine the influence of powder chemical composition on the features and properties of sprayed cast iron splat and coating by spraying three cast iron powders of different chemical compositions on Al-Si-Cu alloy. The effect of powder chemical composition on graphite formation and microstructure was investigated. In addition, the mechanical properties such as friction, wear resistance, and microhardness of sprayed coatings with those powders were examined. The influence of chemical composition of sprayed powders on the microstructure of cast iron coatings was examined by X-ray and SEM.
A New Spray Coating Process for Manufacture of Stainless Steel Clad Construction Steel with Resistance to Corrosion by De-icing Salts & Seawater
Authors: Chesney Peter 
Published: September 2022

Abstract
The world’s first plant for manufacture of stainless steel clad structural steel is now operational in the USA. The process consists of coating round steel billets with a spray of stainless steel. A metallurgical bond is achieved so that the billets can be reheated and hot worked into long products while retaining the integrity of the coating. The process consists of teeming stainless steel from a ladle into a spray chamber and atomizing the emerging stream with jets of nitrogen to form a spray of semi-liquid particles. The spray is directed onto a 140mm diameter preheated carbon steel billet to form a thick coating (4 – 5mm). The spraying rate of 50Kg/minute produces clad billet at the rate of 15tonnes/hr. Billet is then hot rolled in a conventional bar mill to make corrosion resistant clad steel sections such as rebar and dowel pins. Coating thickness after rolling is in the range 0.5 – 1.0 mm depending on the final section. Clad products have a life expectancy of 75 – 100 years in high chloride environments such as tidal zones, bridge decks and highways treated with de-icing salts. The spray coating process is described together with mechanical properties of the clad bar and results of corrosion tests. The economics of stainless clad steels vs. other corrosion resistant materials are reviewed.
Marine Exposure Tests of Thermal Sprayed Coatings in Japan
Authors: Kuroda S. , Kawakita J. , Takemoto M. ,   Thermal Spray Committee
Published: September 2022

Abstract
The thermal spray committee of the Japan Association of Corrosion Control (JACC) has been conducting a marine corrosion test of thermal sprayed Zn, Al and Zn-Al coatings since 1985. Twelve kinds of sprayed coating were deposited onto steel pipes by arc- and flame-spraying to varied thickness and subjected to various post-spray treatments. The samples were set vertically into seawater at a port 80 km south from Tokyo. Corrosion performance of these coatings has been inspected annually by recording the appearance and coatings’ thickness at sea air-, splash- and tidal-zones. No significant changes were observed for five years exposure. After 7 years, however, Zn coatings with and without sealing started to suffer degradation in the immersed portion. Contrary to this, Al and Zn-Al coatings still exhibit superb corrosion performance. The test will continue till 2006 to complete the test period of 20 years. In order to place the test into a proper perspective, we also conducted a survey on the corrosion prevention by thermal spray technology in 2001, collecting more than 170 published reports and asking experts to contribute reviews on various aspects of the technology. This paper first describes several topics from the survey report to explain the past and the present situation of thermal spraying for corrosion prevention in Japan. Then, the corrosion performance of sprayed coatings in the exposure test during 15 years will be summarized.
Optimization of Heat Transferring Components under Severe Wear Stress Conditions
Authors: Wielage B. , Wank A. , Reisel G. , Gross U. , Barth G. 
Published: September 2022

Abstract
There is a variety of components, which are subject to high wear and/or corrosion stress on the one hand and are used to transfer heat on the other hand. Two examples are drying cylinders in paper production and condensing boilers. Up to now there are no data available for the thermal design of thermal spray coated components except for some MCrAlY and thermal barrier coatings for turbine applications. Also guidelines for the optimization of thermally sprayed coatings concerning heat transfer including the effect on the wear resistance are missing. HVOF sprayed cermet coatings are widely used for combined wear and corrosion protection these days. In addition to WC-CoCr 86 - 10 4 and 75 Cr3C2 - 25 Ni20Cr conventional Ni5Al and Ni20Cr bond coats are evaluated concerning their thermal conductivity in the range between room temperature and 600 °C. Also the thermal contact resistance is determined depending on the substrate material: mild steel S355J2G3 (1.0570), grey cast iron GG25 (0.6025) and austenitic stainless steel X5CrNi18-10 (1.4301, AISI 304). The applied Laser- Flash method requires knowledge of the heat capacity, thermal expansion and density, which are determined before. HVOF spraying has only negligible influence on the heat capacity of WC-CoCr feedstock, as the temperature depending functions are almost identical. The use of spraying feedstock with average WC particle sizes of 800 nm, 3 µm and 5 µm permits to investigate the influence of the specific surface area of the hard phases both on the thermal conductivity and wear resistance. Furthermore the influence of the coating porosity is determined. In accordance to the drying cylinder application the wear resistance is determined by Taber-Abraser wear tests. Bond coats are produced by HVOF, HVCW and arc spraying and compared concerning microstructure and thermal conductivity. A comparison to the properties of electroplated hard chromium coatings is drawn.
Corrosion of WC-Co-Cr Cermet Coatings using In-Situ Atomic Force Microscopy
Authors: Souza V.A.D. , Neville A. 
Published: September 2022

Abstract
Most of the early applications of thermal spray coatings were focused towards providing a remedy to excessive wear degradation. However, as the introduction of such coatings into wider industrial sections increases there is also exposure to other potential degradation processes - aqueous corrosion is one such process. The complex microstructures in cermet coatings have been shown to translate to complex modes of corrosion attack. In this paper an electrochemical test methodology to probe the local/micro aspects of corrosion initiation and propagation will be described. A new electrochemical cell has been devised in which the corrosion can be followed `live` and in `real time`. The surface is subjected to in-situ imaging by Atomic Force Microscopy (AFM). This paper reports some of the exciting findings which have enabled the sequence of corrosion events in cermet coatings to be defined. The study has revealed that a precursor to coating degradation is the attack of the Co-base matrix. This sets up an environment which can catalyse WC dissolution. The practical and fundamental importance of the results will be discussed.
Relation Between Abrasive Wear and Microstructure of HVOF Cermet Coatings
Authors: Li C.-J. , Wang Y.-Y. , Ji G.-C. , Ohmori A. 
Published: September 2022

Abstract
HVOF cermet coatings have been widely used to improve the wear resistance. In the present study, an abrasive wear model is proposed according to the examination of wear mechanism. The relation between the relative abrasive wear and the size and content of carbide particles in cermet coating is established. HVOF WC-Co and Cr3C2-25NiCr coatings are deposited to correlate experimentally the relation between the carbide particle size and abrasive wear. The microstructure of coatings is examined using scanning electron microscopy (SEM). The carbide particle size in the coatings is measured according to SEM images of the coating. It has been found that experimental results correlate with the theoretical model well. The abrasive wear of HVOF carbide cermet coating is determined by carbide size and content. The relative abrasive wear resistance will be increased with an increase in carbide content and the decrease of square root of relative carbide particle size.
Plasma Sprayed Stainless Steel Coatings Doped with Graphite Particles : Study of their Dry Friction Coefficient Against 100C6 Steel Using a Pin on Disk Test
Authors: Harir A. , Ageorges H. , Grimaud A. , Fauchais P. , Platon F. 
Published: September 2022

Abstract
A new process has been developed to incorporate graphite particles in a stainless steel coating during its formation. Four means have been tested to inject the graphite particles outside the plasma jet and its plume : graphite suspension, a graphite rod rubbed on the rotating sample, powder injection close to the substrate with an injector or an especially designed guide. The latter process has been shown to be the most versatile and the best controllable one. It allows to incorporate uniformly between 2 and 12 vol % of graphite particles (2-15 µm) within the plasma sprayed stainless steel coatings. A 2 vol % seems to give the best results : a low decrease (6%) of the coating hardness and the best results in dry friction studied with a pin on disk set up. In this case, depending on the sliding velocity (0.1 to 0.5 m/s) and loads (3.7 to 28 N) the dry friction coefficient against a 100C6 pin is reduced by a factor between 1.5 and 4 compared to that obtained with plasma sprayed stainless steel.
Effect of Post-Treatment on the Corrosion Behaviour of HVOF-Stellite 6 Coatings
Authors: Malayoglu U. , Neville A. , De Wet D. 
Published: September 2022

Abstract
Coatings obtained by thermal spray techniques are widely used in many industrial applications where wear and abrasion resistance is required. High Velocity Oxy-Fuel (HVOF) spraying represents the state of the art of such types of coatings. The high velocity of the particles achieved during the spraying process and relatively low temperatures at the point of application enhance bond strength and eliminates substrate deformation by thermal effects. These aspects make the process attractive for high value components. In this work the electrochemical behaviour of both as-sprayed and HIPed Stellite 6 coatings are compared. Hot Isostatic Pressing (HIPing) consists of simultaneous applications of high pressure and high temperature. In this paper HIPing has been used as a post-treatment process for HVOF coating. Electrochemical DC anodic polarisation corrosion experiments were conducted in seawater at 18°C, 30°C, 40°C, 50°C, 70°C and 90°C. To support the electrochemical tests, detailed microscopy was conducted after corrosion tests to determine the attack mechanisms.
Steam Oxidation Resistance of HVOF Thermal Sprayed Ni-Cr Coatings
Authors: Sundararaian T. , Kuroda S. , Itagaki T. , Abe F. 
Published: September 2022

Abstract
HVOF coatings of 80Ni-20Cr and 50Ni-50Cr powders were carried out on 9Cr-1Mo steel substrate. The coating thickness was around 60 µm. The coated specimens were steam oxidized in four different temperatures, ranging from 600 to 750°C. The steam oxidized specimens were taken out from the chamber at 10, 100 and 1000 hours to examine their protectiveness against scale growth. X-ray diffraction, scanning electron microscope and electron probe microanalysis were carried out on the steam-oxidized specimens in reference with as-coated conditions. Both 80Ni- 20Cr and 50Ni-50Cr coatings show neither scale growth at the interface nor de-lamination in the coating structure. Fe, and Ni diffusion was found in the case of 80Ni-20Cr coatings. The diffusion increased with increase in the temperature and test duration. On the other hand, 50Ni-50Cr coatings, showed an excellent performance in all tested temperatures. The effect of Cr content in the coating, change in phase and compound formation during oxidation, and their influence on the diffusion process will be discussed in detail.
Low Friction Metallic Coatings for Reducing Railroad Squeal
Authors: Wei W. , Kootwijk P.A.A. 
Published: September 2022

Abstract
Squeal or screech continues to be a major noise pollution problem for rail systems in heavily populated areas. Squeal is a result of stick-slip phenomena in tight curves and switches at relatively low speeds, where the wheels "crab" through the turn. Current solutions for the problem have focused on lubricating the rails with a number of liquid systems including water and greases. However, commercially available systems have only shown mixed success, not only in terms of reducing squeal itself, but also from an economic and environmental standpoint.
Characterization of Coatings Deposited by Laser-Assisted Atmospheric Plasma Spraying
Authors: Zieris R. , Nowotny S. , Berger L.-M. , Haubold L. , Beyer E. 
Published: September 2022

Abstract
Laser-assisted atmospheric plasma spraying (LAAPS) is a newly developed one-step coating process in which the laser beam interacts simultaneously with the plasma torch on the substrate or deposited coating surface in order to generate the coating. LAAPS combines the advantages of plasma spraying, such as high coating rates, with those of laser cladding. In addition, there is no need for a special surface preparation method, such as grit blasting. In this paper, the principle of LAAPS is described and the use of this process for the preparation of NiCrBSi and Al2O3- 3%TiO2 coatings is demonstrated. The coatings were characterized by optical microscopy, hardness and bond strength testing, X-ray diffraction measurements, and an oscillating sliding wear test. Coating microstructures and properties were compared to those of APS coatings. The bond strengths of LAAPS coatings were higher for NiCrBSi coatings, but they were lower for Al2O3-3%TiO2 with a NiAl bond coat due to the very complex processes occurring in the contact region between the metallic substrate and the ceramic coating material.
On Vacuum Plasma Spray Forming of Ti-6Al-4V
Authors: Leblanc L. , Tsantrizos P. , Salimijazi H.R. , Coyle T.W. , Mostaghimi J. 
Published: September 2022

Abstract
The growing need for new materials and material combinations with superior properties for severe service applications has led to the development of near net-shape forming techniques for certain materials, such as superalloys, refractory metals and highly reactive metals, including Titanium and its alloys. In this work, the vacuum plasma spraying process (VPS) was optimized to prepare dense spray-formed components from high purity plasma atomized Ti-6Al-4V powder. VPS offers a unique environment for spraying reactive materials such as Ti- 6Al-4V as a controlled inert atmosphere is used during deposition of the material. Three particle size distributions of the powder were used to investigate the influence of the starting powder characteristics (size, chemical composition) on the resulting spray-formed material. Post-deposition heat-treatments were subsequently applied to modify the deposit structure in order to improve their mechanical properties. The as-deposited and post-treated specimens were characterized for their internal microstructure and mechanical properties. Results indicate that a combination of high purity starting powder, controlled environment, and tailored deposition and post-processing conditions can be used to produce dense spray-formed Ti-6Al-4V structures with properties comparable to those of cast and wrought materials. Yield strength in the order of 800 MPa, with ultimate tensile strength close to 900 MPa and elongation near 10% were measured for spray-formed and heat-treated Ti-6Al-4V specimens. The results of this investigation on vacuum plasma spray forming of Ti-6Al-4V are presented in a series of two papers. The first one (this one) focuses on the preparation of the spray-form components, and on the resulting mechanical characteristics. The second paper is dedicated to the detailed characterization of the internal microstructure of the as-sprayed and heat-treated deposits, and the correlation with the measured mechanical properties.
Investigation of the Influence of Post-Treatments on the Mechanical Properties of Coated Aluminium Foams
Authors: Maurer Matthias , Zhao Lidong , Lugscheider Erich 
Published: September 2022

Abstract
Beams of a hardenable aluminium foam were coated using electric arc spraying. AlSi6 and XCr13 were sprayed using compressed air or nitrogen. Subsequently the aluminium foam – coating - composites were post treated. The post treatment comprised of a heat treatment, suitable for hardening of the foam, grinding, shot-peening and / or sealing of the coating. Young’s moduli of the composites were non-destructively measured by resonant frequency. The dynamic properties of the composites were investigated by four-point-bending fatigue tests. The influence of the different post treatments on the bending stiffness and the fatigue behaviour was analysed using a statistical approach.
Determination of the Moving Velocity of Preheating Gun During Preheating/Spraying/Cooling Process by a Function Specification Method
Authors: Liao Hanlin , Deng Hao , Verdy Christophe , Coddet Christian 
Published: September 2022

Abstract
Disk-shaped splats that can be obtained on a heated substrate reveal a better contact with the substrate surface, resulting in a better adhesion/cohesion of coatings. Some research results illustrate that when the substrate temperature exceeds the transition temperature, the ideal splat can be obtained. In the simultaneous preheating-spraying-cooling process, named HEATCOOL in which a preheating gun heats the specimen just before the spraying and a cooling jet cools it just after the spraying, the preheating temperature is of short duration. In order to study the preheating effect and determine the optimal velocity of the movement of the system for obtaining an appropriate preheating temperature, the function specification method, an optimisation method, was adopted combined with FEM (the finite element method). An oxy-acetylene flame was used as preheating thermal resource, the optimal velocities were estimated. Particle impact tests of Cu and YSZ (ZrO2- 8%Y2O3) powders sprayed by plasma with a flame heating system were carried out with different moving velocities. The splats morphology collected on stainless steel and aluminium plates were observed to clarify and confirm the calculated results.
Plasma Sprayed Coatings Using Different Nanosize Alumina Powders
Authors: Zeng Yi , Ding Chuanxian , Lee Soowohn 
Published: September 2022

Abstract
Three kinds of nanostructured alumina coatings were prepared by air plasma spraying. As-sprayed coatings were characterized by SEM and XRD. Their surface roughness, porosity and microhardness were also examined. Results indicated that the smaller the size of the starting powders, the better the properties of the coating. The differences in the phase composition of the as-sprayed coatings could be used to explain the differences observed in coating properties.
New Composite Coatings on the Base of Recycled Hardmetals
Authors: Zimakov Sergei , Tarbe Riho , Kulu Priit 
Published: September 2022

Abstract
A new class of composite powders for thermal spray on the base of recycled hardmetal powder is proposed. WC-Co hardmetal powder that is either alloyed/mixed, coated, agglomerated or cladded with binder metal - cobalt enhances the technological properties of spraying powders and enables the producing of sprayed composite coatings with double-cemented structure. The manufacturing technology of WCCo/Co composite powders composed of mixing, agglomerating, sintering and crushing was studied and characteristics of the produced spray powders by particle size, morphology of particles and specific surface area were evaluated. The experiments for deposition of coatings by high velocity spraying processes (HVS), detonation gun (DG) spraying and High Velocity Oxy-Fuel (HVOF) spraying were carried out. Comparison abrasive erosion wear tests of sprayed coatings were performed.
Stainless Steel Coatings Alumina Reinforced by Plasma Spraying Mechanofused Particles
Authors: Cuenca-Alvarez R. , Ageorges H. , Fauchais P. 
Published: September 2022

Abstract
Stainless steel particles have been covered with an alumina shell by the mechanofusion process in order to reinforce stainless steel coatings by uniformly distributed alumina particles. Two stainless steel particle size distributions (PSD) in the range of 65 µm and 120 µm were tested. It was found that the mechanical energy input induced a spherical shape of the final composite particles with a controlled shell thickness (3 µm and 2 µm respectively) without forming new phases that usually take place during the mechanofusion process. The new spherically-shaped composite particles were sprayed in air with a D.C. plasma torch working with an Ar/H2 mixture as plasma forming gas. At mid-flight, two types of composite particles were detected : the first case corresponded to well molten particles where all the alumina shell has flowed to the tail of the particle ; the second case was related to particles which still retained some evidence of the alumina shell uniformly distributed around the stainless steel core. When the mechanofused particles were sprayed onto a cold smooth substrate (stainless steel 316L, Ra&lt;0.05 µm), the resulting splats were extensively fingered and became disk shaped when the substrate surface was preheated over 300°C. However, alumina was either spread exactly on the stainless steel splat corresponding to well molten particles or dispersed in fingers and frozen over the surface of the stainless steel splat corresponding to particles covered by the broken alumina shell. An important effect of fine particle size on in-flight droplet behavior is detected because the center of gravity is more decentred than that of coarse particles influencing the deposit build-up. The composite stainless steel/alumina coatings sprayed on a rough stainless steel substrate (Ra = 6.7 ± 0.3 µm) preheated to 200 °C are compared to those of pure stainless steel. Hardness and adhesion/cohesion of deposits formed with fine particles were found to be improved comparatively to a pure stainless steel deposit. However, when coarse particles are used, the value of hardness is decreased and works is in progress to understand this phenomenon.