bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proporties of Thermally Sprayed Coatings on Magnesium Parts for Enhamcement of Wear and Corrosion Resistance
Authors: Lugscheider E. , Parco M. , Bach Fr.-W. , Möhwald K. , Engl L. 
Published: August 2022

Abstract
The technical and economical potential of innovative materials is gaining growing interest for technologically orientated companies. The use of lightweight materials is an extremely important consideration, especially when designing moving components (e. g. in aerospace, automotive or machine construction). Magnesium is a promising alternative to other lightweight materials, such as aluminum and titanium, due to its relatively high specific strength and stiffness. Further advantages are high thermal conductivity and good joining and machining capabilities. However, the use of magnesium alloys is restricted by relatively poor wear behavior and corrosion resistance. In order to overcome the limitations associated with magnesium alloys, a project was founded by the Materials Science Institute (MSI), at the RWTH Aachen, and the Institute of Materials Science (IW), at the University of Hannover, to deal with the application of wear and corrosion protective coatings on Mg alloys by means of thermal spraying. A variety of coating materials were applied on Mg substrates using several thermal spray processes (like Arc Spray and HVOF). The coatings were then characterized particularly with regard to their wear and corrosion properties. To further enhance the overall corrosion resistance two additional approaches were investigated. On the one hand various duplex coating systems were designed and applied. With the objective of decreasing the open porosity coatings were either densified by shot peening or sealed by applying organic sealers on the other hand.
Impact Behaviour of HVOF-Sprayed WC-CoCr Coatings
Authors: Reisel G. , Steinhäuser S. , Wielage B. , Hockauf M. , Meyer L.W. 
Published: August 2022

Abstract
In some applications like car armouring for personal safety, in bulk containers in pebbles working, in off-shore applications or in offroad-vehicles, impact of bodies with different sizes and high velocities has to be calculated in material design. A possibility to design under economical aspects is to use to low-cost material as substrate with a protective coating on its surface instead of using expensive bulk materials. One conceivable material system to be used as protective coating is WC-CoCr, which is usually applied by HVOF and shows high hardness combined with a good toughness of the matrix. These properties are very important for dissipation of the impact energy and for high fracture toughness. In the presented case study, WC-CoCr coatings with different carbide sizes were produced with the JP5000 system from TAFA. Projectiles with high velocities of more than 250 m/s were shot by an experimental shooting device on the coatings and for comparability on the uncoated substrate. Impact tests were done with balls and cylinders with varying impact angles between 10° and 90°. The powders and the coatings were characterized by means of microscopy and XRD. Furthermore, the hardness of the coatings was measured. After impact tests, the coatings were investigated with optical microscopy. In the case of ball impact, a significant dependency can be found between the impact behaviour and carbide size. Coatings with coarse carbides show the lowest impact depth. The dependency of the impact depth of coatings with one carbide size on their hardness level is relatively low. No dependencies of the carbide size or the hardness level can be found for impact with cylinders.
Influence of the Grit Blasting Process on the Properties of Thermally Sprayed Coatings
Authors: Buchmann M. , Fischer M. , Spence D. , Wenzelburger M. , Riegert-Escribano M.J. , Gadow R. 
Published: August 2022

Abstract
The quality and operation performance of layer composites manufactured by thermal spraying is influenced by two different processes, the activation process of the surface prior to coating deposition and the coating process itself. The activation of the substrate surface is mainly performed by grit blasting operations. Surface activation by grit blasting is used in order to improve the bonding between substrate and coating, which is strongly related to the size and nature of the surface topography and roughness generated by the blasting process. Besides the roughening effect, grit blasting induces compressive residual stresses into the substrate surface which can be critical especially for thin walled components, e.g. piston rings, where the component shape is an important factor for the operation behavior and functionality. Another effect is an increase of hardness in the surface region related to the induced compressive stresses. A variety of blasting parameters can influence the surface characteristics, like nozzle diameter, grit medium and size, blasting pressure, distance and time. The influence of these parameters on the surface roughness, hardness, component deformation and residual stresses was investigated by tactile surface metrology, universal hardness and Almen tests as well as experimental residual stress analysis with the incremental hole drilling and milling method. All investigations were performed on rectangular steel strips. The results are discussed concerning quality control features for grit blasting processes in serial production.
Stress-Relaxation and Creep Behavior of Heat-Treated Stand-Alone Plasma-Sprayed 7 wt.% Y2O3-ZrO2 Coatings
Authors: Petorak C.A. , Bowman K.J. , Trice R.W. 
Published: August 2022

Abstract
Plasma-sprayed 7 wt.% Y2O3-ZrO2 (YSZ) stand-alone coatings were subjected to 10, 50 and 100-hr heat treatments at 1200°C, followed by mechanical testing in compression at 25°C, 1050°C, and 1200°C. The mechanical tests performed on the samples included cyclic loading/ unloading, stress-relaxation, and creep. In cyclic compression tests at 25°C, it was observed that the YSZ coating that had been heat-treated for 50-hr at 1200°C demonstrated a higher modulus and more strain hysteresis as compared to an as-sprayed sample. As heat-treatment time increased, the YSZ stand-alone coating demonstrated less relaxation of the initial applied stress for stress-relaxation tests run at 1050°C and 1200°C. The steady-state creep rate was observed to decrease with increasing heat-treatment time prior to testing; as expected, the steady-state creep rate increases when the testing temperature was increased from 1050°C to 1200°C. Density (via Archimedes’) and phase analysis (via X-ray diffraction) were performed on YSZ coatings before (i.e. as-sprayed) and after heat-treating at 1200°C. Porosity was observed to decrease only slightly (~1%) after a 100-hr heat-treatment at 1200°C as compared to the as sprayed porosity. The high-yttria metastable tetragonal phase observed in the as-sprayed coatings was observed after a 100-hr heat-treatment at 1200°C. The same metastable tetragonal phase was also observed after a 100-hr heat-treatment at 1200°C followed by a 3-hr stress-relaxation test at 1200°C.
Fatigue and Mechanical Properties of Nanostructured vs. Conventional Titania (TiO2) Coatings
Authors: Ibrahim A. , Lima R.S. , Marple B.R. , Berndt C.C. 
Published: August 2022

Abstract
Nanostructured and conventional titania (TiO2) powders were thermally sprayed using APS and HVOF processes. The fatigue and mechanical properties of the coatings investigated. Coatings were characterized using SEM to investigate the microstructural features and Vickers indentation to determine the hardness. SEM analyses were also carried out on the fracture surfaces of fatigue-tested samples to assess crack nucleation and to study the mechanisms of deformations. The fatigue strength of coatings deposited onto low-carbon steel (AISI 1018) showed that the nanostructured titania coated specimens exhibited significantly higher fatigue strength compared to the conventional titania
Investigation of Ceramic and Hardmetal Coatings in an Oscillating Sliding Wear Test
Authors: Zieris R. , Berger L.-M. , Schulz I. , Martens S. , Enžl R. 
Published: August 2022

Abstract
The present study was carried out within the scope of a project oriented toward the evaluation of applicability of different materials as thermally sprayed coatings for gear flank protection. Investigations were made on APS deposited oxide coatings, such as Cr2O3 and Magnéli phases of different systems, as well as on hardmetal coatings based on WC, Cr3C2 and TiC deposited by HVOF. All coating microstructures were investigated by optical microscopy, with selected samples studied additionally by SEM. Phase composition, hardness, Young’s modulus and fracture toughness were other basic coating properties studied. An oscillating sliding wear test was used as the main tool for preliminary evaluation before more laborious testing. The wear resistance in this test was investigated against 100Cr6 for all materials as well as against sintered silicon nitride and sintered WC-Co for oxide and hardmetal coatings, respectively. Hardmetal coatings based on WC and TiC showed the best results and were selected for further testing.
Wet Spray Coatings for Heavy Equipment Industry
Authors: Revankar G. 
Published: August 2022

Abstract
The paper presents a wet spray method as an alternative to the thermal spray process when post-spray fusion of the coating is required to improve coating density and obtain a metallurgical bond to the substrate. The relatively new wet process [1] has been successfully used to apply alloy metal powders to ferrous substrates such as steels, grey and ductile iron, and other iron alloys. Since a majority of wear parts used in the heavy equipment industry are made of steels and irons the technology is found applicable to a large number of ferrous parts for reducing wear and extending life. The process has advantages over the thermal spray process in that it is much less expensive and can be applied to a much greater thickness without concern for pre-fusion coating stress and spalling. In this work, a commercially available iron based alloy powder was applied to several heavy equipment parts to produce wear and corrosion resistant coatings that were evaluated through laboratory and field tests. Many of these parts are now in production. The paper gives the process details and its current status, presents test data, and discusses its advantages and limitations over the thermal spray process.
Statistical Modeling of Thermal Spray Welding of Steel-Shaft Materials for Wear Resistance
Authors: Jawwad A. , Al-Bashir A. 
Published: August 2022

Abstract
Thermal spray processes are widely used in industries to compensate for worn surfaces of different power transmission steel shafts. These include plain carbon, alloyed and stainless steels. This comes as a means of saving the worn parts by reusing them after they have been thermally sprayed by suitable wear-resistant coatings. As there are several factors to be controlled in this process, this makes it necessary to get the best combination of process parameters to provide the required level of wear resistance and, hence part life. In this study the oxy-fuel process is applied to 4140 alloy steel. Process parameters have been varied using a 2k experimental design. The Pin-on-Disc test was used to estimate the wear resistance of the different material-coating-parameters combinations. The data were analyzed and a statistical model, explaining the effect(s) of different parameters as well as their interaction, was obtained.
Full Mechanised Cladding of 3-Dimensional Components in Constrain Position with the PPAW-Process
Authors: Wilden J. , Bergmann J.P. , Trommer M. 
Published: August 2022

Abstract
The industrial set of PPAW-cladding has gained a higher importance in the last few years. The process is characterised by high quality layers of about 1-2 mm with a low dilution of about 5 % and without intermediate layers. The great amount of different alloys, which can be processed as powders, opens a wide range for industrial applications. Manually PTA-cladding can be performed in different working positions. Presently the full mechanised PTA-cladding process is carried out in horizontal position. Thus the components have to be moved relative to the plasma arc. In order to improve operating efficiency and flexibility when processing wear and corrosion resistant coatings it is necessary to enlarge the working area and to set strategies for cladding in constrain position. The effect of the gravitation force leads in this case to a very difficult governing of the pool, which flows downwards and affects the quality of the coating. Basic knowledge of the mechanised process depending on the cladding position, for example with industrial robots, is not available at the moment, even if this is necessary when cladding huge heavy components. The present work shows coating strategies as well as the influence of process parameters while cladding steel with corrosion and wear resistant powders in constrain position (bottom-up and top-down). Investigations with Ni- and Co-based alloys were examined and the suitability for constrain position was evaluated. Through an optimisation of the heat input it was possible to influence positively the melt flow and to carry out successfully coatings. Finally the transferability was successfully proven on a complex three dimensional component.
Manufacture and Properties of Segmented Thermal Barrier Coatings
Authors: Vaßen R. , Szulc M. , Guo H. , Stöver D. 
Published: August 2022

Abstract
Thermal barrier coatings (TBCs) made of yttria stabilized zirconia (YSZ) are frequently used in gas turbines to improve their efficiency. Coatings typically applied on combustion chamber parts with a thickness of more than about 500 mm often contain segmentation cracks. This type of cracks considerably improve the thermal cyclic life of the thick TBCs. Segmentation cracks can be directly introduced into the coatings during the plasma-spraying process. The influence of the most important process parameters as substrate temperature and passage thickness on the segmentation crack density will be described in detail. In addition to the coatings with thickness values of about 1 mm also thin coatings with segmentation cracks have been developed. This type of coating might also be favourable for an application on blades and vanes of gas turbines. The thermal cycling performance of all coatings was tested in gas burner test facilities. The thick, segmented TBCs almost reached the performance of conventionally sprayed thin TBCs. The thin, segmented TBCs showed an excellent performance at surface temperatures above 1300°C which was considerably better than that of conventionally sprayed thin TBCs. Possible explanations for the observed improvement of the thermal cycling behaviour by the introduction of segmentation cracks will be given. Abstract only; no full-text paper available.
Surface Modification Induced by the Pulsed Nd-YAG Laser Irradiation in the PROTAL Process
Authors: Li H. , Costil S. , Coddet C. , Barnier V. , Oltra R. 
Published: August 2022

Abstract
In the PROTAL process, a pulsed (10ns) laser irradiation is introduced to prepare the surface simultaneously to the thermal spraying process. The purpose of the laser pre-treatment is to eliminate the contaminants and generate a surface condition favorable to the coating adhesion. This study aims at clarifying the fundamental aspects of laser irradiation effects on metallic substrates. The broad technical applications, which involves various surface conditions, may lead to different phenomena and hence limit our comprehensive understanding of the laser-material interaction. Therefore, all specimens were mechanically polished to a mirror state before the laser treatment, which allows the same surface state. Both morphological and chemical surface modifications were investigated by optical microscopy, SEM observation, roughness measurements. Formation of dispersed craters, which takes place at the superficial defects location, dominates the surface modifications due to localized laser ablation.
Non Destructive Resting of the Coating-Subsrate Interface of Thermally-Sprayed Industrial Parts Non Destructive Testing of the Coating-Substrate Interface of Thermally-Sprayed Industrial Parts
Authors: Ducos M. , Bossuat B. , Walaszek H. , Canal B. 
Published: August 2022

Abstract
The present work deals with the application to actual in industrial conditions of the promising results of the study on adhesion, as presented at the previous edition of ITSC’2004 in Osaka, Japan. These industrial parts were typical of those produced in workshops for aircraft-aerospace, petro-chemical, printing works industries etc…. Thermal spray processing of industrial parts tested in this study are numerous, primarily air plasma spraying (APS), HVOF and conventional flame spray with or without remelting. Ultrasonic NDT facilities are now installed in an actual industrial workshop and show the reliability of the testing method and related results. For every tested part, digital ultrasonic testing was carried out to be compared to results from conventional adhesion tests according to EN 582 standard. U.T. results were quite in keeping with those from EN 582 testing. However, in addition, ultrasonic testing exhibited the any heterogeneity when existing, (local weak zones) at the coating-substrate interface. This resulted in easy discriminating of adhesive areas from cohesive areas. Results of this work obtained in a real workshop environment leaves promising expectations for ultrasonic testing to meet results from conventional EN 582 adhesion testing when applied to industrially-produced parts. Ultrasonic testing results in a low-cost NDT method which should compete with current high-cost control. Moreover, ultrasonic NDT looks more reliable in so far as the whole part can be controlled due to scanning of the whole surface.
Modern Gas Supply Concepts for Thermal Spraying
Authors: Krömmer W. , Heinrich P. , Rickfält C. 
Published: August 2022

Abstract
The gas industry not only offers the most effective gas for all thermal spray processes, it also provides a variety of supply concepts and hardware with which maximum profitability can be achieved. The operator of the thermal spray equipment is responsible for ensuring that sufficient gas quantities are available at all times, comparable to the logistics involved in spray material management. Linde is now offering a fully automatic gas supply concept, including everything from consultancy and installation, through to the types of gases which can be used. The customer can therefore choose to manage his stocks himself as before, or to have the gas delivered and the bundles replaced by the supplier. With a minimum of time and effort, this electronic aid enables a reliable and fail-safe gas supply
Thermal Spray Particulate and Its Challenges for Dust Collection Equipment
Authors: Abelson J. 
Published: August 2022

Abstract
Thermal spray particulate presents unique challenges for in-plant dust collection. Regulations about particulate level emissions are becoming increasingly stringent. This paper will discuss the thermal spray environment and technologies that can be useful in the mitigation of airborne particulate. First, a discussion of basic filtration concepts - The many methods that are used to collect particulate (diffusion, inertial impaction, interception, and sieving) and an explanation of each with an understanding of when each methodology is used. We will also explore the properties of the typical thermal spray particulate - particle size analysis of typical resultant thermal overspray process dust including actual test data and scanning electron microscope photos. The structure of the filter media is vital to achieve superior filtration performance. A unique filter media technology for this application will be discussed, including media construction and characteristics of its use. Finally, the filter media must function within a system. A brief discussion of dust collection technology and the dust collection system will describe a solution to the problems of thermal spray particulate.
The Development of a High Efficiency Supersonic Plasma System
Authors: Zhang P. , Liang Z. , Wang H. , Xu B. , Zhu S. 
Published: August 2022

Abstract
A high efficiency supersonic plasma spray system (HEPJet) was successfully developed with a maximum power of 80 kW and a maximum working gas flow of 6 m3/h. It can be used to spray metallic, carbide and oxide powders. The supersonic plasma spraying gun has a single-anode, internal feeding structure. The development of 80 kW inverse power supply with 20 kHz PWM IGBT circuit solved the problems of high output voltage, high output current and strong interference of high frequency. The production cost of this system is only equivalent to that of ordinary plasma systems. The average velocity of Al2O3 particles in the plasma jet measured with a Oseir Spray Watch system reached 740m/s, and the coatings show high quality, good bonding strength and low porosity. The Co/WC coatings deposited by HEP Jet avoided the degradation from WC to W2C which should be attributed to the strong adjustability of the system for jet temperature and jet velocity.
Irregularity Parameter and Sphericity of Plasma Sprayed Nickel Powders
Authors: Selvarajan V. , Kumar S. 
Published: August 2022

Abstract
Thermal spray coatings of surfaces with metal, alloy and ceramic materials for protection against corrosion, erosion and wear is an intense field of research. The technique involves injection of the powder into a plasma flame, melting, acceleration of the powder particles, impact and bonding with the substrate. Feedstock powders of thermal spray applications have to meet several requirements. Particle shape, size and its distribution, powder flow characteristics and density are the important factors to be considered in order to ensure high spray efficiency and better coating properties. For smooth and uniform feeding of powders into the plasma jet, the powder particles have to be spherical in shape. In the present investigation powder particles are fed into the thermal plasma and spheroidized. The plasma was generated in a dc atmospheric plasma spray torch operating in non-transferred mode. Plasma processed powders were allowed to cool in atmospheric air inside a plasma reactor. The particle while free fall and cooling got spheroidized by surface tension forces. The feedstock powders were in the size range from 40 to 100 microns. The processed powders were analyzed through XRD, SEM/ Optical microscopy and irregularity parameter (IP) and roundness factor were determined. The same parameters were determined through theoretical methods and compared with experimental results.
Thermal Fatigue Testing of Ceramic Coatings Produced by Water-Stabilized Plasma Gun
Authors: Jakubov M. , Ctibor P. 
Published: August 2022

Abstract
Plasma sprayed coatings, thanks to their specific structure, are considered for applications with thermal shocks. Alumina, Alumina-Titania as well as less common spraying materials like mullite, forsterite and ilmenite were selected for testing. Carbon steel coupons were used as substrate. Flame-sprayed bond coats of Ni-Cr and Ni-Al under plasma sprayed ceramic coating were applied for comparison in selected cases. Two different regimes were used to simulate high and low temperature thermal cycling. Before the test and after given number of cycles coating's adhesion was tested by a standard tensile test (EN 582). After the test also the microstructure of samples was observed to evaluate the damage mechanism. It has been proved that Titania addition to Alumina improves the adhesion of coatings under thermal cycling, especially for the coatings without any bond coat. All materials had higher adhesion after each given number of cycles with bond coat than without. Cracking occurred dominantly on the boundary with the base in the case of pure Alumina and mullite while a cohesive cleavage is preferred in ilmenite and combination of both types is typical for other tested materials.