bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Coatings Made by Brazing
Authors: Rass I. 
Published: September 2022

Abstract
In principle, coatings made by brazing is a process variant of brazing which can be classified as high-temperature brazing. It is a thermal process which is carried out either without flux in a vacuum or under inert gas with tapes/slurries/pastes/powders with a liquidus temperature generally above 900 °C. In this process, no components are firmly connected to each other but brazeable materials are applied which, after the heat treatment process, produce a metallic, material-tight coating. The most commonly used filler matrix materials are nickel-based ones, cobalt, iron, copper-based ones or corresponding alloys. Hard materials are mixed in depending on the coating function. Carbides, silicides, borides, oxides, diamonds, CBn or hard material mixtures can be used as hard materials. Common industrial used hard materials are WC, CrC or NbC. Hard material proportions in the coating can be up to 80 Vol.%. Actual developments show contents up to 90 Vol.% and more. Depending on the application, layer matrix hardnesses are flexibly adjustable from 20-30 HRC to 62-65 HRC. The coating produced can therefore perform various functions. For this reason, they are also called functional coatings. For example, hard material particles introduced into the matrix can be firmly brazed onto the surface of the component and thus take on a wear protection or gripping function. Alternatively, worn components such as moulds or turbine blades can be recontoured by brazing suitable materials as tapes or slurries into the wear areas and then reworking them. The coatings are very dense and crack-free and are therefore also very suitable for corrosion protection, even at high temperatures. In contrast to deposit welding, the deposit-brazed coatings are relatively smooth and often do not need to be reworked or ground. The strength of high-temperature brazed hard material coatings can reach the strength of the base materials. This results in a highly stressable layered composite. 2D and 3D geometries can be coated both internally and externally. Coating thicknesses are usually ranging from 1.0 up to 4.0 mm. Minimum layer thicknesses of 0.05-0.1 mm up to 10 mm and more can be achieved. Recent developments also show the possibility of locally brazing on applied tapes or suspensions using laser energy without having to heat the entire component. By selecting appropriate morphologies of the starting powders for braze matrix materials and hard materials, the coating system can be specifically optimised and adapted for the respective application. In addition, work is being carried out on systems in which "signaling elements" are incorporated into the coating in order to record the condition of a surface during operation. For example, forces, wear or temperature. The lecture gives an overview of selected processes, materials and applications and an outlook on new developments.
Additive Manufacturing by Thermal Spray Deposition of Metals on 3D-Printed Polymer Substrates
Authors: Ramaraju R.g.v. , Chandra S. 
Published: September 2022

Abstract
Metals were deposited on components made by 3-D printing with polyvinyl alcohol (PVA), a water-soluble polymer. The polymer was then dissolved, leaving a metal layer whose surface topography was the negative of that of the polymer. This is a rapid and low-cost alternative to 3D printing directly using metal, but to succeed it is essential for the sprayed metal to adhere to the polymer substrate. Tests were done in which aluminum and copper were sprayed using a twin-wire arc spray system onto 3D printed coupons, 50 mm x 50 mm in size, made from polylactic acid (PLA), PLA mixed with metal (aluminum, copper) or carbon fiber, and PVA. Adhesion depended on substrate roughness (minimum 1-2 μm) and substrate temperature (above the glass transition temperature but below the melting temperature of the polymer). It was shown that surface features could be made with high resolution on metal components using this technique.
Fatigue Properties of Cold Sprayed Bell Metal
Authors: Kovarik O. , Daniel J. , Cizek J. , Kondas J. , Cech J. , Siegl J. , Singh R. 
Published: September 2022

Abstract
Mechanical and fatigue properties of cold sprayed (CS) Cu20Sn bell metal were tested in order to assess the potential applicability of the technology to repair impact areas of church bells. The CS bell metal was compared to its traditional cast counterparts, a fine-grained Cu22Sn bell metal seen in small bells, and a coarse-grained Cu20Sn seen in large bells. Similar to other CS metals, it was shown that both the strength as well as the fatigue crack growth rates at low loading are similar to the cast materials. The fracture toughness of the CS material was comparable with the finegrained Cu22Sn bell metal, while both were significantly lower than the coarse-grained Cu20Sn bell metal. The impact damage rate of the CS material determined by a periodic impact test was significantly higher than the (finegrained) cast material. Both materials showed a stabilized, very slow damage rate after the relatively fast initial crater formation. The results presented in this paper identify CS as a feasible restoration technology for church bells, and the introduced methodology presents a characterization method for quantitative description of bell metal impact damage.
Performance of Suspension Sprayed YSZ Thermal Barrier Coatings on Inconel 718 Substrates Produced by Laser Powder Bed Fusion
Authors: Toma F.-L. , Gruber S. , Selbmann A. , Tkachenko S. , Kunze O. , Zabransky K. , Leyens C. , Čelko L. , Tajmar M. 
Published: September 2022

Abstract
Additive Manufacturing (AM) processes offer geometrical freedom to design complex shaped parts that cannot be manufactured with conventional processes. This leads to new applications including aerospace propulsion systems where the Ni-superalloy based material has to withstand high operating temperatures. In this contribution, the influence of heat treatment and surface conditioning of the additively manufactured Inconel 718 substrates on the thermocycling performance of suspension sprayed YSZ coatings was investigated. The different surface conditions included as-built, sandblasted and milled substrate surfaces with and without heat treatment. YSZ coatings were applied using suspension plasma spraying (SPS) with commercial available suspensions. Thermal cycling tests (FCT) at 1100°C, 1300 °C, and 1500 °C were applied to coating systems until failure occurred. The microstructures of the samples were characterized before and after thermal cycling. The performance of the coatings was mainly influenced by the coating morphology and FCT test conditions and less by the state of the AM substrates. Columnar-like YSZ SPS sprayed coatings on AM Inconel 718 substrates seemed to be a promising candidate for rocket engine applications.
Study on the Microstructure Development in a Laser-Cladded Tantalum Layer
Authors: Yuan K. , Pi Z. , Pang X. 
Published: September 2022

Abstract
In this study, pure spherical Ta powders made by induced plasma sphero technique were used in the laser cladding process. The powders were sent into high-energy laser zone and were melted at the surface of a steel substrate to create a Ta layer. The microstructure development in the Ta layer was investigated in a scanning electron microscope. The results showed that the layer was basically dense with some pore/crack defects. In the layer, typical dendritic crystalline structures were formed. With the help of an energy dispersive spectroscope, Fe was detected in the Ta layer. The top surface had about 5% Fe while at the bottom of the cladded layer 15% Fe was detected. So, the diffusion of Fe upwards occurred. With the participant of Fe, the microstructure of the Ta layer was changed. Thermocalc software was used to simulate the phase constitution at different Ta-Fe compositions. The results by the simulation basically agreed with the experimental observations.
Effect of Nb Content on Structure and Properties of Martensitic Stainless Steel Laser Cladding Layers
Authors: Du K. , Huang E. , Pi Z. , Chen X. , Zheng Z. 
Published: September 2022

Abstract
Laser cladding is a technology that uses high-energy-density lasers to quickly melt and solidify alloy powder on the surface of the metal substrate to form a cladding layer with good performance. The alloy powder composition has a significant impact on the cladding layer performance, including hardness, wear resistance and corrosion resistance. In this work, the effect of Nb content on the microstructure types and phase precipitation rules in the martensitic stainless steel laser cladding layers was investigated through the thermodynamics software. The martensitic stainless steel cladding layers with different Nb content was fabricated on the 45# steel substrate by the laser cladding. The microstructure and element composition of the cladding layers were analysed by the scanning electron microscope (SEM) and the energy spectrum analyser (EDS). The hardness, wear resistance and corrosion resistance of the cladding layers were also discussed. The results show that the amount of Cr element in carbide (boride) gradually decreases, while the amount of Nb element in carbide (boride) gradually increases, with the increasing Nb element content from 0.6 wt.% to 2.2 wt.%. For the performance of the cladding layer, the increase in the content of Nb makes the hardness and wear resistance of the cladding layer increase first and then decrease, but the corrosion resistance gradually increases. Generally speaking, the comprehensive performance is better when the Nb element content in the cladding layer is about 1.4 wt.%. At this time, the microhardness of the cladding layer is about 780.00 HV0.2, and the self-corrosion potential is -350.87 mV.
Coating of Aluminium with High Deposition Rates Through Extreme High-Speed Laser Material Deposition
Authors: Koß S. , Vogt S. , Göbel M. , Schleifenbaum J. H. 
Published: September 2022

Abstract
In the past few years, the Extreme High-Speed Laser Material Deposition (EHLA) process has been used as a coating technology alongside conventional processes due to its unique process characteristics and is an economical and sustainable alternative to traditional technologies. The essential characteristic of the process is that the main energy is absorbed by the powder particles so that they reach the substrate surface in a molten state. Thereby, metallurgically bonded and dense wear and corrosion protection coatings are generated. This leads to significantly higher surface and deposition rates can be achieved in comparison to Laser Material Deposition (LMD), and heat-sensitive substrates can be coated. Moreover, in addition to this resource efficiency, the process is not only economically attractive but also sustainable. To reduce component weights as well as secondary energy consumption, aluminium has become an essential base material in most industrial sectors. Aluminium is not simple to process and the wear resistance is small due to the low hardness in comparison to widely used steels. Various technology solutions are currently being investigated for the coating of aluminium. The low melting temperature of aluminium (approx. 750 °C) poses a great challenge when coating with, for example, iron-based alloys. Another challenge for laser-based systems is the reflectance of aluminium in the wavelength range approx. between 1030-1070 nm of conventional laser beam sources. The high degree of reflection of aluminium is the reason why additive processing quiet challenging is. Therefore, for conventional laser-based processes, laser beam sources in other wavelength spectra, e.g. green or blue, are being developed to improve the processing of aluminium. Currently, commercially available multi-kW lasers in the visible light spectrum are still below the available power of IR beam sources. In the context of this study, the feasibility of coating aluminium using EHLA is investigated. A high power 8 kW IR disk laser of the TRUMPF company is used to determine the maximum possible deposition and surface rate.
Quality Assessment of Thermally Sprayed Stainless Steel Coatings Based on Polarisation Curves with 3.5% NaCl Gel Electrolyte
Authors: Grimm M. , Kutschmann P. , Pluta C. , Schwabe O. , Ernst K. R. , Lindner T. , Lampke T. 
Published: September 2022

Abstract
The development of thermal spray processes usually requires an analysis of the complex coating microstructure. In order to inspect critical areas of a coating, destructive testing methods such as the preparation of cross-sections are commonly used. In this work, the suitability of largely non-destructively measured polarisation curves for the quality assessment of thermal sprayed AISI 316L coatings is investigated. Therefore, a 3.5 % NaCl gel electrolyte was developed to prevent the corrosive medium from infiltrating the porous and micro-cracked microstructure characteristic for thermal sprayed coatings. In addition, a measuring cell based on the 3-electrode arrangement was designed to simplify the setup, reduce the measurement time and enable mobile measurements directly on the component surface at a later stage of development. The effects of process-related differences in the microstructure of HVAF and APS AISI 316L coatings on the polarisation curve was investigated by determining the corrosion current density. The microstructure of the AISI 316L coatings was analysed by optical microscope, SEM and EDS, focussing on the porosity and oxide content. The results clearly show that the potentiodynamic polarisation curves of the AISI 316L coatings differ significantly depending on the spray process used and microstructure created. Even small changes in the oxide content within a coating can be detected. Therefore, electrochemical measurement methods using gel electrolyte offer an interesting opportunity to evaluate the quality of thermal sprayed AISI 316L coatings in a largely non-destructive manner.
Dynamic Impact Wear Analyses of Selected Cobalt Based HVOF Sprayed Coatings
Authors: Houdkova S. , Duliskovic J. , Daniel J. 
Published: September 2022

Abstract
Impact testing appears as a most promising tool for gaining information on coating behavior in load-bearing applications. During dynamic impact test an indenter impacts successively the surface of the coating with constant force and frequency. The deformation of the coated specimen during impact testing is affected by the mechanical properties of both the substrate and the coating. Varying the impact load and the number of impacts, the evolution of coating surface deformation and contact fatigue failures can be observed. In the paper, the influence of dynamic impact load and number of impacts on the resulting impact crater volume and morphology is analysed, and the interpretation of the results in form of Wohler-like dependance is suggested and demonstrated on two types of HVOF sprayed Co-based alloy coatings. The low-number impact craters evolution and subsurface cracks propagation of HVOF sprayed Co-based alloy coatings is analyzed in more detail, by means of 3D optical microscopy and SEM. The results showed, that the higher ability to deform plastically increased the coatings dynamic impact fatigue lifetime. The cracks, responsible for coatings destruction, spread predominantly along the intersplat boundaries in the pile-up area.
Tungsten-Steel Functionally Graded Coatings for Nuclear Fusion Applications Manufactured by Cold Gas Spraying
Authors: Mauer G. , Rauwald K.-H. 
Published: September 2022

Abstract
In nuclear fusion reactors, the first wall is the name given to the surface which is in direct contact with the plasma. A part of it is the divertor which is a device that removes fusion products from the plasma and impurities that have entered into it from the vessel lining. It is covered with water cooled tiles which have to withstand high temperatures and high heat fluxes. Moreover, resistance to neutron bombardment, low tritium absorption and low hydrogen permeation are additional demands. One materials concept under research is the application of a Reduced Activation Ferritic Martensitic Steel (RAFM) as a structural material with a tungsten protective coating. Since there is a considerable thermal mismatch between, a functional graded materials (FGM) concept was proposed. As the formation of undesired intermetallic Fe-W phases as well as oxidation should be avoided, cold gas spraying was chosen as manufacturing process. Two powder blends of EUROFER97 RAFM steel and a fine tungsten powder cut on the one hand and a coarser one on the other hand were tested in different ratios. The coatings were characterized with respect to their porosity and surface structure. Furthermore, the deposition efficiencies for steel and tungsten were determined each. It turned out, that the deposition process is a complex mixed situation of bonding and erosion mechanisms as the deposition windows of these very different materials obviously diverge. Thus, a lower working gas temperature and pressure was advantageous in some cases. Unexpectedly, the coarser tungsten powder in general enabled to achieve better results.
Additive Manufacturing Feasibility of WC-17Co Cermet Parts by Laser Powder Bed Fusion
Authors: Papy K. , Sova A. , Borbely A. , Staerk J.-M. , Favre J. , Roulon Z. , Sijobert J. , Bertrand P. 
Published: September 2022

Abstract
Cermets are composite materials consisting of a ceramic reinforcement and a metal matrix. Conventional tungsten carbide cermet parts containing a cobalt matrix phase are mainly produced by powder sintering. Laser Powder Bed Fusion (L-PBF) is an additive manufacturing technology widely applied for direct fabrication of metal functional parts with complex geometry. The present paper deals with the feasibility study of additive manufacturing of cermet parts by L-PBF using WC-17Co powder. The results showed that parametric optimisation of the L-PBF process allowed the production of solid WC-17Co part. Structural analysis revealed the presence of significant porosity (1.41%) and small-scale cracks in the as-built samples. Post-processing, such as HIP (Hot Isostatic Pressure) significantly improved the structure of manufactured parts. The porosity after HIP was very low (0.01%) and phase analysis revealed that the samples after HIP did not contain the fragile W2C phase. Abrasive wear tests showed that the wear resistance performance of additively manufactured parts was comparable to a reference produced by powder sintering. High values of hardness (around 1100 HV30) were observed for the as-built and HIP samples. The study successfully demonstrated the possibility of manufacturing wear-resistant cermet parts by L-PBF.
Correlation Between Process Parameters and Particle In-Flight Behavior in AC-HVAF
Authors: Bobzin K. , Heinemann H. , Jasutyn K. 
Published: September 2022

Abstract
A computational fluid dynamics model for understanding the HVAF process and the influence of the process parameters on the particle flight properties is investigated. Achieving this objective involves a novel approach to modeling the HVAF process with pressure inlet boundary conditions and integration of the mixing chamber. The study comprises the prediction of the flow fields described by a set of equations consisting of continuity, momentum, energy, and species transport. These equations are then solved with realizable k-ε turbulence model, a two-step chemistry model and eddy dissipation model to simulate the combustion reaction. Consequently, the interaction between the CoNiCrAlY alloy particles and the flow is modeled using a Lagrangian approach considering the forces acting on the particles and the heat transfer. The results show that the combustion chamber pressure is mainly affected by the compressed air and propane parameters. Furthermore, the flight behavior of the smaller particles is significantly influenced by the gas flow, while the larger particles tend to maintain their momentum and energy. Through the simulation model, an in-depth process understanding of the HVAF process can be achieved. More importantly, the model can be used as a tool for efficient process development.
Pendekatan Teknik dan Taktik: Pengaruhnya terhadap Keterampilan Bermain Futsal
Authors: Festiawan Rifqi 
Published: September 2022

This study aims to determine the effect of the Technical approach and tactical approach to the level of futsal playing skills. This research is experimental. The population used is the futsal UKM participants in FIKES Unsoed, totaling 40 people. The sample used in this study was 40 students with a sampling technique that is a total sampling. Data collection techniques in this study used the test. The instrument used in this study was a futsal playing skills test. Data analysis techniques using t-test. The results of this study indicate that there is a significant effect of the practice of a technical approach to futsal playing skills with a Sig (0.002). When seen from the average pretest of 49.05 and the average posttest of 43.01, the Mean Difference figure of 6.04 is obtained, this shows a better chance of 27.25%, the effect of the tactical approach exercise on futsal playing skills stated to have an influence significant with Sig (0,000). When seen from the average pretest of 49.18 and the average posttest of 42.65, a Mean Difference figure of 6.53 was obtained, this indicates that the change is better at 29.36%. Whereas from the results of the independent-t-test it was found that there was no significant difference between the training methods of the Technical and tactic approaches in improving futsal playing skills as indicated by the Sig value (0.890). Conclusion, there is no significant difference between the effect of training using a technical approach and tactics on futsal playing skills

Keywords: Tactic and Technical Approaches, Skills, Futsal.
Koordinasi Mata-Kaki dan Kelincahan terhadap Kemampuan Dribbling Sepakbola
Authors: Marta Ibnu Andli , Oktarifaldi Oktarifaldi 
Published: September 2022

This study aims to reveal the effect of eye-foot coordination variables and agility on dribbling ability. This research method is a quantitative method using regression analysis. The population in this study were all SSB Balai Baru Padang players. The sampling technique was carried out by proportional random sampling, with a total sample of 32 people. Data were collected using The Arrowhead Agility Test to measure agility, Kick the Ball to the Target to measure eye-leg coordination, and to measure dribbling ability used The Short Dribbling Test. The results of the study and data analysis showed that: (1) Eye-Foot Coordination had a direct and significant effect on dribbling ability, the value of sig = 0.026 <0.05 was obtained. (2) Agility has a direct and significant effect on dribbling ability because the sig = 0.000 <0.05 (3) Eye-Foot Coordination and Agility simultaneously affect dribbling ability with a Sig value of 0.000 <0.05 and Y '= 6,117 + 0,316X1 + 0,562X2. In conclusion, there is a significant influence between eye-foot coordination and agility simultaneously on the dribbling ability of Football School players.
Keywords: Eye-Foot Coordination, Agility, Dribbling Ability