bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Bondcoat Surface Characteristics on Lifetime in Suspension Plasma Sprayed Thermal Barrier Coatings
Authors: Gupta M. , Markocsan N. , Li X.-H. , Kjellman B. 
Published: November 2022

Abstract
Development of TBCs allowing higher combustion temperatures in gas turbines is of high commercial interest since it results in higher fuel efficiency and lower emissions. It is well known that TBCs produced by suspension plasma spraying (SPS) have lower thermal conductivity as compared to conventional systems due to their very fine porous microstructure. Moreover, columnar structured SPS TBCs are significantly cheaper to produce as compared to the conventionally used electron beam – physical vapour deposition (EB-PVD). However, SPS TBCs have not yet been commercialised due to low reliability and life expectancy of the coatings. Lifetime of a TBC system is significantly dependent on topcoat-bondcoat interface topography. The objective of this work was to study the effect of topcoat-bondcoat interface in SPS TBCs by changing bondcoat spray parameters and bondcoat surface heat treatment. High velocity air fuel (HVAF) spraying was used for bondcoat deposition while axial-SPS was used for topcoat deposition. Same topcoat spray parameters were used for all samples. Lifetime was examined by thermal cyclic fatigue and thermal shock testing. The influence of surface roughness on lifetime has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition to achieve long lifetime SPS TBCs.
Investigation of Interfacial Microstructures between LZ Splats and YSZ Substrate by HR-TEM
Authors: Chen L. , Yang G.-J. , Li C.-X. 
Published: November 2022

Abstract
Thermally-sprayed LZ/YSZ double-layer coatings are promising candidate for the next generation thermal barrier coatings (TBCs) due to exceedingly low thermal conductivity and superior high-temperature phase stability. However, a delamination failure at LZ and YSZ interface were widely observed during TBCs service. Till today, the interfacial microstructure between LZ and YSZ remains unclear. In the present study, LZ splats were deposited on YSZ substrate to serve as a LZ/YSZ interface. The interfacial microstructure was explored by focused ion beam (FIB) and high-resolution transmission electron microscope (HR-TEM). The interfacial defects at splat interface were clearly observed and thoroughly discussed. These results would shed light on deeply understanding the interfacial failure of double-layer LZ/YSZ coatings.
Comparison of Oxidation Resistance and TGO Zone Morphology of NiCrAlY Plasma Sprayed Coating and Sintered Alloy
Authors: Niemiec D. , Moskal G. , Białecki R. , Adamczyk W. , Kruczek T. , Szymański K. 
Published: November 2022

Abstract
The basic aim of presented article is related with comparison of internal morphology of atmospheric plasma sprayed NiCrAlY coating and sintered alloy obtained from the same feedstock powder. This part of investigations consisted characterization of phases composition and internal morphology characterization by SEM/EDS method. The second level of this comparing process is characterization of oxidation process in both cases. In order to properly perform these tests the top surfaces of sintered sample was sand blasted to the roughness level adequate to surface condition after plasma spraying process. The oxidation tests were performed at temperature 1000 and 1100°C during the time to 1000h of exposure in air. The specimens after determined intervals were moving out from the furnace and characterized by visual inspection of top surface as well as by SEM/EDS method and XRD analysis to characterization of phases generated during oxidation. The special emphasis was on the characterization of TGO zone on cross sectioned samples where detailed assessment of oxides zone morphology was made by SEM/EDS method. The oxide thickness was measured as well with dividing of overall oxides zone thickness on the sublayers related with alumina and spinels formation.
The Influence of Deposition Temperature and Thermal Conductivity of the Substrate on Splat Formation
Authors: Wang J. , Li C.-J. 
Published: November 2022

Abstract
Ni20Cr splats were sprayed onto polished substrates at different preheating temperatures in an argon atmosphere by Low Pressure Plasma Spray to reveal the dominating factor on the effective interface bonding formation. The splat morphology, microstructure and splat-substrate interface bonding were characterized by SEM and EBSD. The interface for examination of typical splats was prepared by FIB. Disk splats were obtained on AISI 304 stainless steel substrates preheated to temperatures of 100 °C (cooling from 350 °C), 350 and 550 °C. Moreover, typical distinct two-zone microstructure feature was observed on the splat surface by SEM and EBSD, including central coarse grain and marginal fine grain. When the preheating temperature was higher than 350 °C, effective bonding formed only in the entire central coarse zone, whereas no effective bonding was observed in the fine grain zone. By using glass, copper, nickel and 304 SS as substrates, it was found that increasing thermal conductivity of metallic substrates has little effect on splat diameter and morphology and however decreased the area fraction of central coarse grain zone. It was revealed that the melt/substrate interface temperature plays a crucial role on the interface bonding formation.
Performance of CoCrAlSiY Alloy Powder
Authors: Zhang S. , Du K. , Peng R. L. , Shi J. , Liu J. 
Published: November 2022

Abstract
The CoCrAlSiY alloy powder with Si mass concentrations of 0, 2% and 5% was prepared in this work. The oxidation kinetics curves of all three kinds of powders after 300 h oxidation at 1000 °C were plotted. In addition, the phase constitution of alloy powder and the distribution of β phase were analyzed by SEM and EDS. Furthermore, the effect of Si-addition on the melting temperature and oxidation resistance of the alloy powder were investigated by DSC-TG from the room temperature to 1400 °C. And the element concentrations at the grain boundary of alloy powder with Si addition of 2% were also analyzed. The results show that the melting temperature of alloy powder decreases as increasing Si content, which indicates that adding Si element could influence on the selective oxidation of Al and Cr elements in the alloy system, and improve the oxidation resistance of CoCrAlY powder. In addition, the weight gain of powder with Si addition of 2% is lowest. And Si element has a enrich tendency in the grain boundary. Therefore, the higher Si content would have a negative effect on the high temperature oxidation resistance of powder.
Effect of Thermal Aging on Properties and Microstructure of AlSi-hBN Coating
Authors: Liu J. , Yu Y. , Liu T. , Yang S. , Cheng X. 
Published: November 2022

Abstract
A commercial abradable coating AlSi-hBN was fabricated by atmospheric plasma spraying and was thermal aged at 450 °C in the atmospheric environment for 1000h. Thermal aging effect on coating abradability, hardness, bond strength and microstructure were evaluated. It was found that coating abradability increased obviously after 2h thermal aging and slightly decreased for extended thermal aging time. A sharp decrease in both coating hardness and bond strength were found after 2h thermal aging and a slow increase occurred with the extended aging time. Relationships between coating properties and microstructure were studied. Decomposition of organic binder and sintering of AlSi matrix metal generated by thermal aging were found to be reasons for coating properties changes.
The Influence of Size and Speed of Drops on the Structure and Properties of Electric-Arc Sprayed Coatings
Authors: Pokhmurs’ka H. , Student M. , Hvozdetskyi V. , Stupnytskyi T. , Posuvailo V. 
Published: November 2022

Abstract
Increase of the pressure of air flow from 0.6 to 1.2 MPa provides the growth of its speed from 300 to 600 m/s. The increase of air flow speed reduces the flight time of drop from the arc to the substrate and them against the prepared surface at higher temperatures. Increase of the pressure of air provides reduction the size of drops and oxides between lamellas as well as improves the mechanical characteristics.
Post Deposition Heat Treatment of Cold Sprayed C355 Deposits for Repair: Microstructure and Mechanical Properties
Authors: Zuccoli M. V. , Sabard A. , Guagliano M. , de Villiers Lovelock H.L. , Hussain T. 
Published: November 2022

Abstract
Cold gas dynamic spray is increasingly used for dimensional repair in the aerospace sector as it is capable of producing dense, oxide-free deposits of significant thickness and with good levels of adhesion and inherent mechanical strength. There is significant interest in extending the application of cold spray deposits to include structural, load-bearing repairs. However, particularly for high strength aluminium alloys, cold spray deposits can exhibit high levels of porosity and micro-cracks, leading to mechanical properties that are inadequate for most load bearing applications. In this work, heat treatment was investigated as a potential means of improving the properties of a cold sprayed Al alloy C355 deposit. C355 alloy deposits were produced using two process gas temperatures (350°C and 500°C) and three gas pressures (40, 50 and 60 bar) using a commercially available HPCS system. Microstructural analysis of the coatings revealed that the optimal microstructure (ca. 1% porosity) was obtained at 500°C and 60 bar. Therefore, coatings produced with process conditions of 500°C and 60 bar were heat treated at 175, 200, 225, 250°C for 4h in air and the evolution of the microstructure and microhardness was analysed. The results show that heat treatment at 225°C can decrease porosity (&lt;0.2%) and retain high hardness (105 HV0.05 vs 130 HV0.05 as-sprayed). Further investigation was performed on as-sprayed and 225°C heat treated deposits. The results show that this heat treatment can halve residual stress (-50 MPa vs -100 MPa as-sprayed), and improve tensile properties (UTS). Therefore, this work has demonstrated that the heat treatment of C355 cold sprayed deposits at 225°C can significantly improve their properties.
Development of High-Performance Cold-Sprayed Nanostructured NI-20Cr Coatings for Harsh Environment of Power Plant Boilers
Authors: Kumar M. , Singh H. , Singh N. , Chavan N. M. , Kumar S. , Joshi S. V. 
Published: November 2022

Abstract
In the current work, Ni-20Cr coatings have been developed for potential use in harsh environments of power plant boilers. A pre-synthesized Ni-20Cr nanocrystalline powder was deposited on T22 boiler steel using cold-spray process. The high temperature oxidation behavior of the coating was investigated under cyclic conditions at 900° C for 50 cycles, so as to understand the kinetics of oxidation. Moreover, high temperature erosion-corrosion (E-C) behaviour of the coating was ascertained under cyclic conditions in an actual boiler at 740 ± 10°C for 1500 hours. The oxidized and eroded-corroded samples were characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) analyses. The microhardness, oxidation and E-C data for the developed coating was compared with an earlier reported cold-spray Ni-20Cr coating, which was developed by using a commercially available micron-sized Ni-20Cr powder. The results showed that the developed coating was found to have 33% high microhardness in comparison with the microstructured Ni-20Cr coating. The oxidation and E-C rates of the steel were found to decrease significantly after the application of the developed coating by 89% and 68% respectively. Moreover the nanostructured coating outperformed the corresponding micro-structured Ni- 20Cr coating with regard to high temperature oxidation and E-C resistance to boiler steel by a significant fraction. The investigated coating was found to have oxidation protective oxides such as Cr2O3 and NiO in its oxide scale and was found to be spallation-free.
High Temperature Hot Corrosion Behavior of Selected Thermally Sprayed Coatings in an Aggressive Environment
Authors: Česánek Z. , Houdková Š. , Schubert J. 
Published: November 2022

Abstract
Cr3C2-25%NiCr, Stellite 6, NiCrBSi and Hastelloy C-276 coatings were deposited on substrate material P91 by HP/HVOF (High Pressure / High Velocity Oxygen Fuel) thermal spraying technology. The resistance against high temperature corrosion was evaluated exposition of coatings to corrosive-aggressive environment in the form of molten salts mixture with composition of 60% V2O5 and 40% Na2SO4 at temperature of 750 °C. Further, coatings were exposed to cyclic conditions. After the corrosion tests, all coatings were analyzed using scanning electron microscope (SEM), and analysis of elemental composition (EDX). Alloys-based coatings showed very similar corrosion mechanism in the selected aggressive environment and the same can be stated about cermet coatings. The obtained results prove that HVOF deposited coatings can replace current surface protection of components in power equipment such as nitriding.
Cold-Gas Sprayed Deposition of Metallic Coatings Onto Ceramic Substrates Using Laser Surface Texturing Pre-Treatment
Authors: Kromer R. , Danlos Y. , Costil S. 
Published: November 2022

Abstract
Cold spraying consists in depositing a variety of metals as dense coatings onto metal surfaces. Indeed, copper, stainless steel, nickel, chromium, aluminum, cobalt, titanium, niobium and other metals can all be deposited, as well as metal alloys according to these base-metals and braze powders. The particle-substrate contact time, contact temperature and contact area upon impact are parameters influencing physico-chemical and mechanical bonds. The resultant bonding arose from plastic deformation and temperature at the interface which illustrates why metal coating cannot be sprayed onto rough ceramic substrates. Laser surface texturing has been used as prior treatment to create specific topography. Metal-ceramic has demonstrated a non-deformation of the substrate minimizing intimate bonds. Particle compressive states indicate anchoring mechanisms for laser textured surfaces. Consequently, cold spraying parameters depend on the target material and a methodology can be established with particle parameters (diameters, velocities, temperatures) and particle/substrate properties to adapt the surface topography. Mechanical adhesion is a key issue in cold spray process. As a result, laser surface texturing is a promising tool to adapt the surface to improve adhesion. Metallization process can be achieved.
Modelling of Heating the Particles of Powders in the New Detonation System
Authors: Rigin A. , Maximov A. , Maximova O. , Parygina S. 
Published: November 2022

Abstract
Detonation spraying is used for applying metal, cermet, polymer and ceramic coatings. The advantages of this technology include good adhesion and density of coatings. Minimal residual stresses in the spray process give the possibility to apply coatings to thin-walled parts and foil. Numerical modeling methods for energy parameters of powder particles give the possibility to predict the interaction of powder particles with the gas flow in and properties of coatings depending on spray parameters. In many cases, existing advantages such as high quality of coatings, little heating of the substrate, efficient and economical use of the powder, make the detonation spray process more attractive in comparison with other spray methods. The new design of D-Gun and software gives the possibility to overcome these limitations and significantly increase the productivity. This result was obtained due to a new design of the valve head, new computer control system, electronics and software that allows the firing rate frequency to be increased, ensure the reliability and extend the maintenance-free lifetime. The paper discusses the results of modeling of acceleration and heating the particles of powders in the new detonation system and also methods of computer simulation of the formation of adhesive contact between powder particles and metal surface.
Adhesive-Corrosion Resistance of High Velocity Metal Droplet on Atmospheric Plasma Sprayed Ni-WSe2-BaF2·CaF2-Y-Ag-hBN Solid Lubricant Coatings
Authors: Yuan X.-J. , Chen X.-H. , Zha B.-L. , Yao C. 
Published: November 2022

Abstract
Adhesive-corrosion resistance is an important issue for the application life of solid lubricant coatings. With abundant metal droplets deposited on the surface of a solid self-lubricating coating, the coefficient of friction of the coating changes and results in adhesive wear. In this paper, a new method for evaluating the adhesive resistance for solid self-lubricating Ni-WSe2-BaF2·CaF2-Y-Ag-hBN coatings was reported. The microstructures and anti-adhesive characteristics under different angles of aluminum metal droplets obtained with an arc supersonic nozzle were investigated for high temperature solid self-lubricating coatings produced by plasma spray. The results demonstrate that the friction coefficient of Ni-WSe2-BaF2·CaF2-Y-Ag-hBN solid self-lubricant coatings is distributed between 0.086 and 0.299 at 25-800℃. The effect of molten metal drops on the coating adhesive-corrosion rate increases with the deposition angle. At 90°, the deposition rate of metal droplets on the coating and substrate surface is maximized, and the hexagonal boron nitride (hBN) self-lubricating coating deposition rate is only 58 mg/(cm2·s). This work demonstrates that hBN can effectively decrease the adhesive layer of the coating by the rate of the polishing and stripping.
Influence of Substrate Properties on the Formation of Suspension Plasma Sprayed Coatings
Authors: Zhao Y. , Yu Z. , Planche M.-P. , Lasalle A. , Allimant A. , Montavon G. , Liao H. 
Published: November 2022

Abstract
In this study, YSZ coatings were deposited on different substrate materials (stainless steel and aluminum) using suspension plasma spray (SPS) technique. The effects of substrate properties (material, surface topology, temperature, and thickness) on the formation of coatings were investigated. The results showed that, with the identical spray parameters, the porosity is higher for the coatings deposited on aluminum than that on stainless steel due to the high thermal transfer ability of the former substrate material. The SEM results revealed that the microstructure of as-prepared coatings could be tailored from the vertical cracked structure to the columnar structure by increasing the substrate surface roughness and their formation mechanisms were discussed. The substrate preheating temperature has an influence on the microstructure of the coatings, especially in the interfacial region and increasing the substrate temperature is an effective means for reducing the interface defects in the coatings. With the increase of the substrate thickness, the quantity of the vertical cracks in the coatings is reduced and their width becomes narrower.
Development of Bondcoat Layer for Long Lifetime Suspension Plasma Sprayed Thermal Barrier Coatings
Authors: Gupta M. , Markocsan N. , Li X.-H. , Östergren L. 
Published: November 2022

Abstract
Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable to produce columnar microstructures similar to the conventionally used electron beam – physical vapour deposition (EB-PVD) process. Moreover, SPS is a significantly cheaper process and can also produce more porous coatings than EB-PVD. However, lifetime of SPS coatings needs to be improved further for them to be applicable in commercial applications. The bondcoat microstructure as well as topcoat-bondcoat interface topography affect the TBC lifetime significantly. The objective of this work was to investigate the feasibility of different bondcoat deposition process for SPS TBCs. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial NiCoCrAlY and PtAl bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue and thermal shock testing. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs.
The Possibility of Using Ultrasonic Waves to Support Suspension Plasma Spraying Process
Authors: Sokołowski P. , Gałafin M. , Kozerski S. , Korzeniowski M. 
Published: November 2022

Abstract
Suspension Plasma Spraying is one of the newest thermal spray processes. It uses liquid feedstock instead of dry powders, as it is in case of conventional Powder Plasma Spraying. The suspension preparation process should be optimized individually depending on the powder material to avoid poor suspension stabilization, fast sedimentation of solids or too high viscosity. However, regardless of the liquid feedstock preparation, each kind of suspension causes some technological problems during spraying. In this study the possibility of using high power ultrasonic waves to support the suspension feeding and injection was investigated. The idea was to break the powder agglomerates before the suspension goes through the injector (in the pipeline system). The in-line ultrasonic dispersion system was designed. The geometry of all important components (transducer, booster and horn) was analyzed and calculated depending on the frequency and power of ultrasounds. By using modal analysis and Finite Element Method (FEM) the propagation of ultrasonic wave was simulated for different sonotrode geometries, called: (i) stepped, (ii) exponential, (iii) catenoidal and (iv) tapered. The in-house system was initially tested in order to see if all elements were designed and manufactured properly. Finally, the ultrasonic cavitation was observed inside the feeding pipeline system, which should allow dispersing the suspension prior to its injection into the plasma jet.
Keterampilan Menulis Teks Eksposisi Siswa Menggunakan Metode Think Pair and Share
Authors: Wahyuni Neneng 
Published: November 2022

The purpose of this study was to determine the effect of the think pair and share method on the exposition of the writing skills of class X SMKN 3 Payakumbuh students. This research method is a quantitative study using the experimental method. The results showed that the mean score of students in the experimental class was 78.37, while in the control class it was 70.62. In conclusion, the think pair and share method affects the writing skills of the exposition text in the experimental class. There is a significant difference in the results of text writing skills using the think pair and share method and conventional methods.
Keywords: Expositional Text Writing Skills, Think Pair and Share
Keterampilan Menulis Dongeng Menggunakan Metode Drill
Authors: Wahyuni Neneng 
Published: November 2022

The purpose of this study was to describe the skills of writing fairy tales using the drill method for seventh grade students of SMP Negeri 1, Guguak District, Lima Puluh Kota Regency. This research method uses quantitative methods with descriptive types. The results showed that the seventh grade students generally got an average score of 82.45 with a range of 76-85% with good qualifications. In conclusion, the skills of writing fairy tales using the drill method in the form of a student's fairy tale framework are classified as very good qualifications, the writing of the subject matter of fairy tales is in good qualifications and the writing of the sequence of story points is also classified as a good qualification.
Keywords: Fairy Tale Writing Skills, Drill Method