bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Way in HVOF Technology—CFD Optimized TopGun AirJet for Powder and Wire
Authors: Wielage B. , Rupprecht C. , Paczkowski G. , Menzen R. , Weissenfels G. , Bernhardt H.-U. , Runkel M. 
Published: September 2022

Abstract
The thermal spray industry requires universal and economical HVOF systems for the production of high-quality coatings with high deposition efficiencies. In the last years classic HVOF guns have been adapted insufficiently to these requirements. This paper shows how modern numeric simulation and new inventions in gas safety engineering enable the development of a spray system for powder and wire feedstock that is optimized especially for the needs of the market. The new IBEDA TopGunAirJet is equipped with an air-cooled ‘de Laval’-like nozzle. The optimized expansion of the gas leads to high gas and particle velocities as well as to moderate flame and particle temperatures. Advantages of the TopGunAirJet are the achievable high coating quality, the low energy consumption (propane, ethene), the utilization of powder or wire and the efficient air cooling of the thermally loaded nozzle parts. Additionally, as a result of the axial powder injection, the free jet divergence and the nozzle wear are minimized. By varying the powder gas flow, the dwell time of the particles inside the flame can be influenced in order to avoid fusing of hard phases. As an example, WC-Co 88-12 coatings are presented and compared to coatings sprayed with a standard HVOF system of the 3rd generation. Different 316L coatings are produced and tested in comparison to standard HVCW coatings to show the workability of solid and cored wires. Finally, extensive LDA measurements are used for in-flight particle analysis, and investigations concerning the achievable deposition efficiencies are carried out.
Homogenization of Coating Properties in Atmospheric Plasma Spraying – Technical Objectives and First Results of a DFG Funded Research Group
Authors: Bach F.-W. , Möhwald K. , Hartz K. , Bobzin K. , Bagcivan N. , Petkovic I. , Schein J. , Forster G. , Zimmermann S. 
Published: September 2022

Abstract
The disadvantage of plasma torches using conventional single cathode techniques is the occurrence of azimuthal and axial instabilities inside the plasma torch. This causes electrical power fluctuations which result in inhomogeneities of the plasma jet enthalpy and with that an uneven plasma particle interaction. Hence, variations in particle properties occur and consequently an uneven coating quality is produced. Using the triple-cathode technique these electrical power fluctuations were successfully reduced, resulting in a stationary plasma flow. Thus this technique appears to offer the potential to homogenize coating properties. Similar results have been shown for plasma torches with triple anode arrangements. The goal of this research group is to homogenize properties of plasma sprayed coatings using of 3-cathode and 3-anode technologies based on numerical simulations. The approach used is to subdivide the complete APS process into the areas plasma torch, free jet as well as coating formation and characteristics. By simulation of the individual areas and combination with experimental results the corresponding process parameters will be obtained for the desired coating properties.
Gaseous Pulse Detonation Spraying: Current Status, Challenges, and Future Perspective
Authors: Kharlamov Y.A. 
Published: September 2022

Abstract
The paper is devoted to gaseous detonation spraying and presents the state of current knowledge, as well as the following research and development needs: gaseous detonation as spraying heat source; operation cycle of detonation guns and its possible versions; operating frequency; impulse jet formation; basic detonation guns design concepts, as fuel and oxidant types, features of barrel design, predetonation distance control, valved and valveless detonation guns concepts, etc.; gas dynamic characteristics of detonation spraying.
Atmospheric IC-Plasma Spraying of Coatings – A Too Little Attended Alternative?
Authors: Dzur B. 
Published: September 2022

Abstract
Although the history of using the thermal inductively coupled RF-plasma (ICP) for spraying processes has been started in the early sixties, up to now all but no industrial applications are known. ICP-spraying of coatings has been investigated in various labs for interesting applications like coatings for medical implants and electrodes for SOFC´s. All the processes are VPS-applications. This on one hand of course is caused by the oxygen affinity of the used materials, on the other hand the current view in thermal spraying is, that very dense and excellent adherent coatings can be sprayed only by increasing the particles velocity. In contrast to this mind this contribution will try to show, that also under atmospheric and low vacuum conditions, i.e. using a laminar flowing plasma with nearly no acceleration of the axially injected particles, it becomes possible to spray coatings with comparable values of porosity and bond strength but special features that can not be produced with common technologies. This can be explained by the changed condition of heating, deformation and cooling down of the considerably larger particles. Actual examples are given for various spraying materials like ceramics and hard magnetic materials.
Thermal Spray Fabrication of Cermet-Supported Tubular Solid Oxide Fuel Cells
Authors: Li C.-J. , Li C.-X. , Yang G.-J. 
Published: September 2022

Abstract
Ni-Al2O3 cermet supported tubular solid oxide fuel cell (SOFC) has been fabricated by thermal spraying processes to aim at reducing fabrication cost. Ni-Al2O3 cermet support was deposited by flame spraying and the anode, electrolyte and cathode were deposited by plasma spraying on the support tube. YSZ-Ni was used as the anode and lanthanum strontium manganate was used as the cathode. Plasma-sprayed ScSZ and YSZ deposits, after post-spray densification treatment by nitrate solution, were used as the electrolyte at thicknesses of 40 µm to 100 µm to assemble SOFC single test cell. It was found that the output power density was increased with the decrease of electrolyte thickness. The cells assembled with ScSZ exhibited a higher powder density than YSZ electrolyte. The maximum output powder density reached 0.89 W/cm2 with ScSZ electrolyte of 40 µm thick at 1000°C in comparison of 0.76 W/cm2 obtained with YSZ electrolyte. The results showed that the tubular SOFC fabricated fully by thermal spray processes exhibits excellent performance.
Effect of Substrate and Cathode Parameters on the Properties of Suspension Plasma Sprayed Solid Oxide Fuel Cell Electrolytes
Authors: Waldbillig D. , Tang Z. , Burgess A. , Kesler O. 
Published: September 2022

Abstract
An axial injection suspension plasma spray system has been used to produce layers of fully stabilized yttria-stabilized zirconia (YSZ) that could be used as solid oxide fuel cell (SOFC) electrolytes. Suspension plasma spraying is a promising technique for the rapid production of coatings with fine microstructures and controlled porosity without requiring a post-deposition heat treatment. This new manufacturing technique to produce SOFC active layers requires the build up of a number of different plasma sprayed SOFC functional layers (cathode, electrolyte and anode) sequentially on top of each other. To understand the influence of the substrate and previously-deposited coating layers on subsequent coating layer properties, YSZ layers were deposited on top of plasma sprayed composite lanthanum strontium manganite (LSM)/YSZ cathode layers that were first deposited on porous ferritic stainless steel substrates. Three layer half cells consisting of the porous steel substrate, composite cathode, and suspension plasma sprayed electrolyte layer were then characterized. A systematic study was performed in order to investigate the effect of parameters such as substrate and cathode layer roughness, substrate surface pore size, and cathode microstructure and thickness on electrolyte deposition efficiency, cathode and electrolyte permeability, and layer microstructure.
Automated Substrate Cooling System for HVOF Coating Operations
Authors: Zurecki Z. , Ghosh R. , Mebrahtu T. , Thayer M.J. , Stringer S.R. 
Published: September 2022

Abstract
High production rate and feed powder efficiency are critical in the HVOF hardfacing of aircraft landing gear, turbine, and actuator components traditionally electroplated with carcinogenic hard chromium. Desired improvements are hindered by rapid heat build-up in substrate component and thermal expansion mismatch between the carbide coating and steel, titanium or aluminum substrate. A new, cryogenic nitrogen gas (-195°C) cooling system has been developed which limits the thermal expansion and substrate softening problems, and enables a non-stop, gun-on-target spraying. Fully automated, the operation of the new AP LIN-Cooling System is based on thermal imaging of the entire substrate and multi-zone cooling with novel, cryofluidic nozzles. Thermal logs and images of components processed are saved by the system for quality auditing purposes. This paper presents results of industrial tests of the system during WC-10Co4Cr coating of Boeing 737 landing gear, demonstrating a 50% reduction in spraying time, corresponding reductions in the consumption of powder and HVOF gases, and additional labor savings due to the use of flexible masking, unfeasible with the traditional cooling methods. Analysis of residual stresses, structures and properties of the coating and AISI 4340 steel substrate shows that the cryogenic nitrogen cooling results in high-quality products.
A Life Cycle Comparison of Hard Chrome and Thermal Sprayed Coatings: A Case Example of Aircraft Landing Gears
Authors: Krishnan N. , Vardelle A. , Legoux J.G. 
Published: September 2022

Abstract
Electroplated hard chromium (EHC) is widely coated onto parts to provide resistance to corrosion, wear and impact. The electroplating process, however, has significant health and environmental impacts. Air emissions during the electroplating process contain hexavalent chromium (Cr+6) - a known carcinogen, furthermore the process is energy intensive and generates hazardous waste. Because of health and environmental issues related to hard chromium plating, there have been several efforts to find alternatives. One of the more efficient technologies among the substitutes is High Velocity Oxy-Fuel (HVOF) thermal spraying. This technology is commercially available today, with a major commercial opportunity in aerospace applications. In this paper, we therefore compare the life cycle environmental footprints of hard chromium and HVOF coatings for aircraft landing gear. Our results indicate that from an environmental perspective, HVOF spraying is generally preferable to EHC plating, with 5-10 times lower human health impacts and 30-50 times lower ecosystem impacts. However, in terms of resource consumption, the processes have similar impact profiles with EHC plating having a potential for lower impact on resources in areas with a significant share of renewable electricity.
HVOF-Sprayed WC-(W,Cr)2C-Ni Coatings and their Properties
Authors: Berger L.-M. , Saaro S. , Jordan C. , Naumann T. , Kašparova M. , Zahálka F. 
Published: September 2022

Abstract
The composition WC-(W, Cr)2C-Ni is one of the standard hardmetal compositions used for the preparation of thermally sprayed coatings by high velocity oxy-fuel (HVOF) spraying. Surprisingly, this composition has been poorly investigated in the past. Frequent use of the commercial designations WC-“CrC”-Ni, WC-Cr3C2-Ni, and WC-NiCr indicate the insufficient knowledge about the phase compositions of the powders and coatings. In this paper, the processability of five commercial feedstock powders was studied. These feedstock powders were of different origin and were sprayed with two different liquid-fueled HVOF systems (K2 and JP-5000). The microstructures and phase compositions of the powders and the coatings were studied. Focus was on the appearance, composition, and distribution of the (W, Cr)2C phase, which is either formed or changes its Cr/W ratio during the spray process. The composition of the (W, Cr)2C phase was estimated from the lattice parameters. Hardness, density, and Young’s modulus were determined for the coatings. Additionally, the abrasion wear resistance of the coatings was studied. Unlike WC-Co and Cr3C2-NiCr, WC-(W, Cr)2C-Ni is not a simple binary hard phase-binder metal composite. The excellent properties of this composition, for instance, its oxidation and corrosion resistance, will surely attract more attention to this composition than it has in the past.
Influence of the Spray Angle on Characteristics for Atmospheric Plasma Sprayed Hard Material Based Coatings
Authors: Tillmann W. , Vogli E. , Krebs B. 
Published: September 2022

Abstract
This paper presents an investigation of the influence of the spray angle on thermally sprayed coatings. Spray beads were manufactured with different spray angles between 90° and 20° by means of atmospheric plasma spraying (APS) on heat-treated mild steel (1.0503). WC-12Co and Cr3C2-10(Ni20Cr) powders were employed as feedstock materials. The spray beads were characterized by a Gaussian fit. This opens the opportunity to analyse the influence of the spray angle on coating properties. Furthermore, metallographic studies of the surface roughness, the porosity, the hardness and the morphology were carried out and the deposition efficiency as well as the tensile strength were measured. The thermally sprayed coatings show a clear dependence on the spray angle. A decrease in spray angle changes the thickness, the width and the form of the spray beads. The coatings become rougher and their quality decreases. In addition, the spray process becomes inefficient as the deposition efficiency declines. Especially, below 30° for Cr3C2-10(Ni20Cr) and below 50° for WC-12Co a significant change in microstructure was observed.
Advanced Knowledge System for Coatings and the Gas Turbine MRO Industry
Authors: Chandler P.E. , Hall W. , Shadbolt N.R. , Alani H. , Szomszo M. 
Published: September 2022

Abstract
The growth of data generated within thermal spraying is, for many, a daunting business. Yet, this growing resource represents a largely untapped and potentially valuable asset capable of providing “knowledge” rather than just “information”. Many companies already use a range of Web based tools. However, the Web itself is changing and the vision for the future, the “Semantic Web”, is set to revolutionise how business will be done. One important aspect of this Web “future” is that web pages will be greatly enriched and data will have additional information (tags) which help to describe it and more significantly, put the data into a context. This will enable machine readability and the use of query languages to ask direct questions. Following on from ideas introduced at ITSC 2007, a proof of concept demonstrator has been built for thermal spray coatings used in the Maintenance Repair and Overhaul (MRO) of gas turbines. A system has been built which stores and manipulates a range of data including; aircraft deliveries, RSS feeds of aircraft sales, engine types, MRO business details, thermal spray coatings and market dynamics. This paper presents the development of this system and discusses its future potential.
Development of Oxide Dispersion Strengthened MCrAlY Coatings
Authors: Bobzin K. , Ernst F. , Richardt K. , Brühl M. 
Published: September 2022

Abstract
MCrAlY materials are widely used as bond coats for thermal barrier coatings on turbine blades. The aim of this work is to improve mechanical properties and wear resistance of thermal sprayed NiCoCrAlY-coatings by strengthening the coating with hard phase particles. In order to retain the effect of the dispersion reinforcement at high temperatures, the use of temperature-stable oxide hard phases such as ZrO2 is necessary. To realise this new material structure, the high energy ball milling process is applied and analysed. With this process it is possible to achieve a homogeneous distribution of the oxide hard phases in the NiCoCrAlY matrix. The mixture ratio between NiCoCrAlY and ZrO2 was varied between 5 wt-% and 10 wt-% ZrO2. The influences of the milling time of the high energy ball milling process on the distribution of the hard phases in the metal matrix were analysed. After spraying with a HVOF system the mechanical properties of the coatings are measured and compared with conventional NiCoCrAlY coatings.
Wire Arc Spraying Technology for Spraying Particle Reinforced Coatings
Authors: Wilden J. , Jahn S. , Reich S. , Fischer G. , Knapp S. , van Rodijnen F. 
Published: September 2022

Abstract
The introduction of new wire arc spraying equipment with chopped power supplies offers many possibilities to improve the wire arc spraying process. These power sources provide higher process stability even at reduced voltages. On the one hand conventional applications can be enhanced and on the other hand new processes can be developed. Due to the high process stability the introduction of additional particles into the atomizing gas stream is possible. This can be applied to produce coatings with a high wear resistance as well as a high surface roughness. A combined technology of particle injection and the productive wire arc spraying process enables the economic production of innovative functional surfaces. In the last years ITSC, the injection of corundum particles had been presented. In this paper further strategies for inserting particles into the gas stream and experimental results are shown for iron based coatings. For the reinforcement different carbides were injected into the atomizing gas stream.
Newest Light Weight Closed-Loop Arc Spray Gun
Authors: van Wonderen M. , Sedov V. , MacMillan I. 
Published: September 2022

Abstract
Within the Aircraft MRO (Maintenance, Repair and Overhaul) business KLM Royal Dutch Airlines Engineering & Maintenance Division has been involved with Thermal Spraying since the late 60’s. The latest procurement on thermal spraying is the state of the art light weight electric arc spray gun (the EM-14) for the closed-loop electric arc spray system of Praxair TAFA called the CoArc. With this new piece of equipment KLM is up-to-date in the high-tech approach of applying thermal spray coatings on aircraft engines with a electrical twin-wire arc spray system. Close teamwork between an end-user in aircraft industry (KLM) and a thermal spray supplier (Praxair) resulted in a new state of the art arc spray gun. This paper shows the first spray results with the EM-14 gun.
Corrosion of Alumina-Based Coatings
Authors: Stahr C.C. , Berger L.-M. , Herrmann M. , Deska D. 
Published: September 2022

Abstract
Corrosion protection has long been a challenge to thermally sprayed coatings. Alumina is known for its good corrosion properties, although especially thermally sprayed alumina-based coatings corrode if exposed to certain environments. The coating therefore becomes the limiting part for the component lifetime. Besides the corrosion of the coatings themselves, corrosion of the substrate can result from the existing porosity in the coatings. This work shows the influence of corrosion on alumina-based coatings as a function of the TiO2 content and the coating process used. The effects of corrosion are quantified to enable lifetime prediction and tailoring of protective coatings. The coatings were analyzed using electrochemical methods and were exposed for long periods to acids and bases at 85 °C. Corrosion properties of the coatings were compared with those of bulk parts, prepared by hot-pressing. An electrochemical method was developed to estimate interconnected of porosity as an alternative to long-term corrosion experiments.
Effect of Al on the Performance of Ni Based PTA Coatings
Authors: Cangue F. , D'Oliveira A. 
Published: September 2022

Abstract
Degradation of components that operate under elevated temperature and carburizing environments involves the diffusion of C and the precipitation of carbides. Industries have been seeking for materials that can withstand these service conditions. The present work aimed to develop coatings to address this challenge through the enrichment of a Ni based alloy with Al. An atomized Ni alloy without Al and different powder mixtures with 15 and 30wt%Al were deposited by PTA on a carbon steel. Coatings were analyzed in the as deposited condition and after temperature exposure in an air furnace and pack cementation tests at 650º and 850ºC. Vickers microhardness profiles under a 500gf load, X-ray diffraction, optical and scanning electronic microscopy were done Results revealed that the presence of Al lead to the development of a complex intermetallic phases which were associated with the enhanced metallurgical stability of the coatings under the tested temperatures. The superior performance of the coatings deposited with the powder mixture containing 30wt%Al after pack cementation was associated with the development of the NiAl intermetallic phase and of the oxide layer Al2O3 that stabilized the microstructure at the tested temperatures and reduced the diffusion of C.
Degradation Behavior of HVOF Sprayed Ni-Based Coatings on Superalloy in 40%Na2SO4-60%V2O5 Environment at 900°C
Authors: Mahesh R.A. , Kamal S. , Jayaganthan R. , Prakash S. , Modi A. 
Published: September 2022

Abstract
High velocity oxy fuel thermal spray (HVOF) processing is one of the proven thermal spray technologies to develop high temperature oxidation and corrosion resistant coatings for various high temperature applications such as thermal power plants, aero turbines, and energy conversion systems. In the present investigation Nickel based coatings, viz. Ni-5Al, NiCrAl, and NiCrAlY-0.4wt%CeO2 were sprayed on Fe based superalloy (Superfer 800) by HVOF spray process as the chosen superalloy finds extensive use steam boilers, furnace equipment, heat exchangers and piping in chemical industry The degradation behaviour of the coated superalloy was studied in the aggressive environment of 40%Na2SO4-60%V2O5 at 900°C, using thermogravimetric technique, to understand the protective nature of the coatings under cyclic conditions. The coatings were found to be effective in increasing the resistance to the degradation in the given environment. Among the coatings investigated, NiCrAlY-0.4wt%CeO2 coating was found to be more protective on the superalloy in the given aggressive environment. The corrosion mechanisms were elucidated through the X-ray diffraction (XRD) analysis and microstructural characterization techniques such as FE-SEM/EDAX analysis of the corroded products formed at high temperature.
Structure and Corrosion Behavior of 316L Stainless Steel Coatings Formed by HVAF Spraying
Authors: Zeng Z. , Sakoda N. , Tajiri T. , Kuroda S. 
Published: September 2022

Abstract
SUS316L coatings were sprayed by a high-velocity air fuel (HVAF) system to reduce oxidation and thereby improve the corrosion behavior of stainless coatings. The effects of powder feed rate and particle size on the microstructure, oxide amount and adhesion strength of the coatings were investigated. The corrosion resistance of the coatings was evaluated by conducting salt spray tests. The oxide amount in the coatings sprayed by the HVAF process is below 7 % and adhesion strength is below 34 MPa. In comparison with those of coatings sprayed by a high velocity oxygen fuel (HVOF) system, the oxide amount and adhesion strength are decreased because the particles heated below the melting point of the alloy and insufficient softened in HVAF process. The coatings deposited are original porous, and they become denser through the impinging effect caused by the following sprayed particles. With the increase of powder feed rate and particle size, there is a tendency of reduction in oxides, and an obvious decrease in adhesion strength. Corrosion resistance of the unsealed coatings is insufficient, and this becomes notable with increasing powder feed rate and particle size. The sealed HVAF coating sprayed with the largest particles shows the best corrosion resistance.