bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual Interfacial Strength in an Air Plasma Sprayed Thermal Barrier Coating After Thermal Cycle Fatigue
Authors: Yamazaki Y. , Yoshida T. 
Published: September 2022

Abstract
Air plasma sprayed thermal barrier coatings, which reduce the temperature in the underlying substrate material, are an essential requirement for the hot section components of an industrial gas turbine. For TBC systems, the adherence of the top coating is one of the most important parameter for the durability of TBC system. In this work, the thermal fatigue behaviour of an air plasma sprayed thermal barrier coating was investigated. In addition, the residual interfacial strength was also evaluated by means of the 4-point bending test. From the measurement of the AE signals during the thermal fatigue tests, micro-cracking occurred in each cooling stage of the thermal fatigue cycles and then such damage depends on the number of thermal cycle. In addition, TGO grew at the interface with the exposed time at elevated temperature (the time dependent damage). Thermal barrier coating undergoes both time dependent damage and cycle dependent one under thermal fatigue condition. The life of thermal cycle with high temperature dwell time is shorter than not only that of isothermal exposure but also that of thermal cycle without dwell time.
Effect of Spray Torch Nozzle Design Modifications on Arc and Plasma Jet Characteristics and Coating Properties
Authors: Outcalt D. , Suzuki S. , Vincenzi L. , Heberlein J. 
Published: September 2022

Abstract
In order to identify means to improve plasma spray consistency, various modifications to the design of a commercial plasma torch nozzle have been investigated. The modifications consist of preparing anode inserts with grooves in the axial direction (spline insert), and introducing a fraction of the plasma gas through a ring of micro-nozzles surrounding the anode nozzle (micro-jet ring). Different designs for each modification have been investigated, and these modifications have also been paired with a modified upstream gas injector. For each of the modified designs, a wide range of characteristics have been measured for the arc, the plasma jet, the in-flight particles and the coating. The results show that most nozzle modifications lead to higher particle velocities and temperatures. The plasma jet is significantly elongated by using some of the modified nozzles, and the cold gas entrainment somewhat reduced. The arc voltage and the luminosity fluctuations are little affected by the nozzle modifications, however, the modification of the gas injector does change the frequencies of the fluctuations. Each of the nozzle modifications can be easily implemented offering an economical way to enhance process reliability.
Influence of Parameters on Volt-Ampere Characteristic of Plasma Arc in High Velocity Plasma Spraying
Authors: Yang H. , Wang L. 
Published: September 2022

Abstract
The plasma torch is one of the most important equipment during air plasma spraying, is used to produce the plasma arc in the nozzle for the acceleration and heating of particles. The voltage-current characteristic of the plasma arc is very important to the fusion of particles. The volt-ampere characteristic is affected by many factors, such as gas species, gas flow rate, nozzle geometry and the type of gas injection. So the factors influencing the voltage-current characteristics in high velocity plasma spraying were studied. As the results showed, the arc voltage is increased with the increase of the primary gas flow rate in some range. The secondary gas flow rate has an important effect on the electric arc voltage. The influence of nitrogen on the arc voltage is more than argon when they are chose as the primary gas in plasma spraying. The arc voltage is decreased with the increase of the nozzle’s compression angle and the decrease of the nozzle’s aperture, when the length of the nozzle is unvarying.
Characterization of Cold-Sprayed Nickel, Titanium, and Copper Coatings for Process and Property Optimization
Authors: Rezaeian A. , Chromik R.R. , Yue S. , Irissou E. , Legoux J.-G. 
Published: September 2022

Abstract
The properties of pure Cu, Ni and Ti cold spray coatings on mild steel substrates were examined. Samples were prepared using CGTTM Kinetics 3000 system varying gun temperatures from 200 to 600 °C and gun pressures from 10 to 30 bars with N2 as propelling gas. For these conditions, deposition efficiencies and critical velocities were characterized. In addition, the microstructural and mechanical properties of coatings were examined.
Manufacturing of Diamond Abrasive Wheel from Ni Coated Diamond/Bronze Composite Feedstock Through Kinetic Spray Technology
Authors: Na H. , Bae G. , Kumar S. , Lee C. , Kim H.J. 
Published: September 2022

Abstract
Manufacturing of diamond abrasive wheel has been achieved through kinetic spraying in order to simplify the manufacturing process and improve the mechanical properties. However, size of the initial feedstock diamond particles is reduced by fracturing during the process. Uniform distribution of diamond particles in the coating layer is significantly important for obtaining grinding properties of diamond abrasive wheel. In this study, optimized nickel thin film which is coated around the surface of diamond particle was used to prevent the fracture of diamond particles during spraying and improve the properties. Thickness of the nickel thin film was optimized by ABAQUS 6.7-2 finite element analysis software as 3 µm for 20 µm diamond and bronze particles. Fraction and size distribution of the diamond particles present in the coating were analyzed through Scanning Electron Microscope (SEM) and Image analyzer methods.
Comparison of a High-Purity HOSP PYSZ Powder with Standard HOSP—Powder-Coating Characterization and Thermal Cycling Testing
Authors: Gray S. , Lawson K.J. , Dorfman M.R. 
Published: September 2022

Abstract
A high-purity (HP) HOSP (Hollow Oven Spherical Process) PYSZ powder has been evaluated and compared to standard PYSZ powders. The main difference is these two powders is the starting raw material purity. Four TBC systems (2 standard types and 2 high purity versions) were Air Plasma Sprayed (APS) onto CMSX-4 substrates with APS CoNiCrAlY bond coats. Thermal shock testing was performed to 50 % spallation at 1135°C with 1 hour hot cycles with forced air cooling. The as-deposited coatings and those after thermal shock failure were characterized using X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The thermal cycling results show little difference in the thermal shock resistance of the coatings with all failing in an adhesive manner with failures occurring in excess of 180 hot cycles. XRD and Raman data is used to identify the levels of monoclinic and tetragonal phases present in each coating and SEM analysis used to identify differences between PYSZ with a broad particle size distribution and a tighter controlled PYSZ particle size distribution.
Low Pressure Gas Dynamic Spray of Hydroxyapatite Composite Coatings
Authors: Leshchynsky V. , Weinert H. , Maeva E. , Maev R. 
Published: September 2022

Abstract
Hydroxyapatite Composite (HAC) Coatings made by Low Pressure Gas Dynamic Spray (LPGDS) on the grit blasted Ti alloy substrate were studied. The powder feedstock for the HAC coating by LPGDS was prepared by mixing HA powder with Phosphate Glass particles in polyvinyl alcohol, drying and stirring. As-sprayed HAC films on the substrate were heat-treated by two steps (400-500°C and 600-900°C) and their physical characteristics were investigated by scanning electronic microscopy (SEM), X-ray diffractometer (XRD). During sintering-heat treatment, HA particles were consolidated and melted to form a dense and homogeneous coating layer which exhibits the grain structure. Application of HA-glass feedstock is found to be effective for Cold Spray HA based coatings.
Synthesis and Suspension Plasma Spraying of Hydroxyapatite Fine Powder
Authors: Jaworski R. , Pierlot C. , Pawlowski L. , Bigan M. , Quivrin M. 
Published: September 2022

Abstract
The synthetic hydroxyapatite (HA, Ca10(PO4)6(OH)2) is a very useful biomaterial for numerous applications in medicine, especially in view of using as fine powder for suspension plasma spraying. The powder was synthesized using aqueous solution of ammonium phosphate (H2(PO4)NH4) and calcium nitrate (Ca(NO3).4H2O) in carefully controlled experiments. The synthesized fine powder was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The powder was formulated into water and alcohol based suspension and used to carry out the initial tests of plasma spraying onto titanium substrate. The phase analysis of sprayed coating was made with the used of XRD.
Thermal Spraying as a Manufacturing Technology for Light Metal MMC; Experimental and Numerical Process Analysis
Authors: Silber M. , Dongmo E. , Gadow R. , Wenzelburger M. 
Published: September 2022

Abstract
For the manufacturing of metal matrix composites, a combined process of thermal spraying followed by forging in the semi-solid state can be applied. In previous work, it has been shown that thermal spraying leads to a globular microstructure that is suitable for semi-solid forming. Thereby, penetration of the spray material into the reinforcement phase leads to reduced matrix flow paths and thus reduced forming time and fiber disarrangement during the forming process. The main requirement is a low substrate and coating temperature during matrix deposition. By control of the process temperature, geometrical accuracy of the prepreg material and it’s handling between each process step can be significantly improved, leading to an economical method that is a superior alternative to the well established MMC processes like diffusion bonding or squeeze casting. Moreover, due to low process temperatures and process time during matrix application, chemical attack of carbon fiber reinforcements can be reduced. Process development for the manufacturing of continuous fiber reinforced prepregs was focused on the analysis and control of particle properties and substrate temperature. In order to improve the temperature control during arc wire spraying, numerical process analysis of the cooling system was applied. Particle in-flight analysis with the SprayWatch system was used to obtain direct spray parameters as input data for the numerical models. The simulation results were verified by experimental infrared thermography of the substrate during coating. By the use of an optimized cooling system, dense coatings without cracks were achieved with different coating thickness, thereby tailoring the fiber volume content of the final MMC component.
New Health and Environment-Friendly Iron Based Materials Employed as Binders for Carbide Powders used in Thermal Spraying
Authors: Zimmermann S. , Gries B. , Fischer J. 
Published: September 2022

Abstract
Cobalt containing carbide powders such as WC-Co and WC-Co-Cr for thermal spraying exist in numerous modifications varying in chemistry, carbide size, and production method. They are widely used for wear, erosion and corrosion protection in many industrial fields. However, for decades it has been well-known from the hard metal industry that WC and Co containing hard metals in breathable dust form can provoke severe lung diseases if inhaled. Recent examinations have proven that this toxicity can be significantly reduced if the Co is pre-alloyed by Fe. In thermal spraying employees are also dealing with Co containing carbides, for example in powder and coating production. Therefore, in order to reduce the hazards for health and the environment, a new class of agglomerated and sintered carbide powders using Fe based binder materials have been developed and investigated. In the present study the powders were HVOF sprayed in order to examine the influence of their different composition and morphology on the microstructure and the properties of the coatings in comparison to standard materials. The experiments comprise microstructural examinations, wear and corrosion tests.
Metallization of Plastics by Detonation Spraying
Authors: Ulianitsky V. , Shtertser A. , Zlobin S. , Smurov I. 
Published: September 2022

Abstract
Metallization of plastics by thermal spraying is studied. The possibility to obtain high adhesion of metal particles to the surface of a wide range of plastic materials is shown. Powders are sprayed with a new generation detonation gun “Dragon” designed at Lavrentyev Institute of Hydrodynamics SB RAS. The apparatus is characterized by a high-precision gas supply system and a dosed localized powder feeding system. Computer control provides a flexible programmed readjustment of the detonation gases energy impact on powder particles which is a key factor in precision control of spraying parameters for low-melting point powder materials. It is found that under certain spraying conditions molten particles of a low-melting point material not only do not provoke erosion of plastic material at their high velocity impact on the substrate but strong-bond fusion, sufficient to further form a thick coating, occurs. Aluminium, zinc and tin powders are sprayed on substrates from fibreglass, polyester, fluoroplastic and some other plastics. Load capacity of the obtained coatings reaches 100 kg/cm2. It is shown that on top of a thin layer from a low-melting point powder material high-melting point metals and even ceramics can be deposited.
Residual Stresses in HVOF- and APS-Deposited AI2O3 and Cr2O3 Coatings
Authors: Bolelli G. , Lusvarghi L. , Varis T. , Turunen E. , Leoni M. , Scardi P. , Azanza-Ricardo C.L. , Barletta M. 
Published: September 2022

Abstract
Residual stresses in plasma-sprayed Al2O3 and Cr2O3 coatings, deposited using commercial powders, and in HVOF-sprayed ceramic coatings, deposited using conventional Al2O3 and Cr2O3 feedstock and nanostructured- Al2O3 feedstock, were studied by combining X-ray diffraction, substrate chemical removal technique and analytical modelling. The in-situ curvature technique was also employed for HVOF-sprayed Al2O3 coatings, for further verification. Both HVOF-sprayed Al2O3-based coatings display similar, tensile residual stresses (≈120 MPa) near the top surface and possess moderate through-thickness stress gradients (≈10 - 20 MPa). Plasma-sprayed Al2O3 possesses a smaller through-thickness stress gradient and a larger near-surface stress (≈220 MPa): this latter result seems to be due to higher quenching stresses in APS Al2O3, as determined by analytical computation The analytical model is validated by its fairly good agreement to the experimental results obtained both by substrate chemical removal and by in-situ curvature. Cr2O3-based coatings possess a lower near-surface residual stress (≈20 MPa); the HVOF one also exhibits a very large stress gradient (≈80 MPa). Machining and sliding processes (like polishing and dry sliding tribological testing) change their surface residual stresses to compressive ones.
Three-Dimensional Simulation of Porosity in Plasma-Sprayed Alumina using Microtomography and Electrochemical Impedance Spectrometry for Finite Element Modeling of Properties
Authors: Amsellem O. , Madi K. , Borit F. , Jeulin D. , Guipont V. , Jeandin M. , Boller E. , Pauchet F. 
Published: September 2022

Abstract
Moving from a 2-dimensional to a 3-dimensional approach to microstructure and properties has been expected eagerly for a long while to result in a dramatic increase in the knowledge of thermally-sprayed processes and coatings. To meet these expectations, in the present work, microtomography and electrochemical impedance spectroscopy (EIS) were carried out to simulate the microstructure of plasma-sprayed alumina. As-sprayed and excimer laser-processed deposits were studied. Some unexpected but relevant results, e.g. regarding pore orientation in the coatings, could be obtained. EIS simulation led to the establishing of an electrical circuit equivalent to the microstructure which simulated the insulating properties as a function of interfaces and pore interconnection. The latter was studied by microtomography. From this 3-dimensional simulation, a finite element analysis of mechanical properties was developed and compared to experimental measurements. Using this approach to microstructure and properties, excimer laser surface processing was shown to be an innovative process to modify insulating characteristics of plasma-sprayed alumina.
Mullite-Zircon Thermal Barrier Coating Production by Plasma Spraying Process
Authors: Toplan N. , Ustel F. , Toplan H.O. , Erdogan G. 
Published: September 2022

Abstract
Zircon (ZrSiO4) is a technologically important oxide ceramic material known for its high refractoriness and chemical stability. It shows excellent thermal shock resistance as a result of its very low thermal expansion coefficient and a low heat conductivity coefficient. Plasma spraying is a convenient method to produce large area coatings with high growth rates, necessary for many applications. ZrSiO4 is among the least expensive spraying materials for refractory applications. In this study, a single-step process was used to prepare mullite/zirconia ceramic composites by plasma spraying zircon/alumina mixtures. Mixtures of ZrSiO4 and Al2O3 powders with Al2O3 to SiO2 molar ratios of 3:2 were milled for 2 h in a zirconia medium using a ball mill. The as–milled powders were dried in the furnace and sintered at 1300 and 1350 °C for 2h then crushed to a size less than 100 μm. The powders were sprayed by an atmospheric plasma spray gun (Metco 3MB) using C/C+SiC ceramic matrix composite substrates. Scanning electron microscopy (SEM) was used to analyze the microstructures of the powders and plasma coatings. The phase composition analysis of the powder showed the presence of alumina and zircon. After plasma coating, alumina, zircon, and zirconia phases were determined.
Thermal Behaviour of Thermally Sprayed CaZrO3 Coatings
Authors: Garcia E. , Cano C. , Osendi M.I. , Miranzo P. , Coyle T.W. 
Published: September 2022

Abstract
CaZrO3 coatings were alternatively prepared by air plasma spray and flame spray processes. The microstructural characteristics and crystalline phases of the coatings were comparatively studied as a function of the spraying temperature achieved with each technique and the stand off distance. Image analyses were used to estimate their porosity. Thermal diffusivity was measured on free-standing thick coatings using the laser flash technique. Thermal conductivity was obtained from the experimental thermal diffusivity and density data. The hardness of the coatings was evaluated by Vickers indentation tests. Finally, different thermal treatments were carried out to evaluate the evolution of the crystalline phases and the properties of the coatings.
Bioactivity of Micro-Plasma Sprayed Yttria Stabilized Zirconia Coating
Authors: Wu Y. , Li Z. , He D. , Zhao Q. , Li H. , Li H. 
Published: September 2022

Abstract
Yttria-stabilized zirconia coatings were deposited onto a Ti-6Al-4V substrate through a microplasma spray technique and incubated in simulated body fluid (SBF) for different periods of time (3, 7, 14, 28 days). The formation of apatite on the surface was investigated to evaluate the bioactivity of the coatings. Surface morphologies and structural changes in the coatings before and after immersion were analyzed by optical microscopy, scanning electron microscopy, and x-ray diffractometry. The calcium (Ca2+) concentration in the solutions was measured directly after the samples were removed, using an inductively coupled plasma atomic emission spectrometer (ICP). The results showed that yttria-stabilized zirconia coatings can be produced by microplasma spraying and, even though the coatings contain few small unmelted particles, apatite can be formed on the coatings that are soaked in SBF solution. These results indicate that the yttria-stabilized zirconia coatings exhibited definite bioactivity.
Over Ten Years of Quality Assurance, Education and Training in Thermal Spraying
Authors: Huber R. , Ohliger-Volmer A. 
Published: September 2022

Abstract
Since 1993 education and training guidelines and as well as qualification standards of thermal spray personnel have been created step by step by the European Committees of EWF (European Federation of Welding, Joining and Cutting) and CEN (European Committee or Standardisation). ISO personnel qualification and quality management standards result together with the EWF education and training guidelines in a sound QM-system, which meets the increased demands of trade and industry of high quality sprayed coating. Meanwhile about 13 ETS courses were held at the German Welding Institute. Also ETS courses have been held in Finland. The EWF education and training course of the ETSS European Thermal Spraying Specialist will be offered by the German Welding Institute in Munich - SLV München - for the eleventh time in October 2008. DIN EN ISO 9000 series are commonly valid, that is why the product related quality management EN ISO 14922 ”Quality Requirements of Thermally Sprayed Structures, part 1 - 4” was created. This standard series puts principles for the fitness of the purchaser and of his spray production. The QM-system that was established by the GTS e.V.– the Association of Thermal Sprayers – was pioneer and does an excellent job concerning its requirements. The QM-standards are also involve the important ISO standards of the Thermal Spraying Co-ordinator and the Approval Testing of Thermal Sprayers.
Slight Change in Direction
Authors: Grimenstein L. 
Published: September 2022

Abstract
Each year a large number of papers are given at the International Conference. During your time at the conference, you will have the opportunity to hear of the latest developments in technology. Some of the presentations will be done by some of the best in the Thermal Spray Industry doing research and others from equipment and material suppliers. There are others, done by suppliers, who actually are doing the thermal spray applications on a large variety of parts. However even though the R & D papers have a lot of good scientific information a large amount of it is non usable in the industry. So, who should be changing directions?
Numerical Simulation of the Thermo-Mechanical Behaviour of Thermally Sprayed Abradable Coatings
Authors: Seichepine J. , Faraoun H. , Peyraut F. , Chandler P. , Coddet C. , Sporer D. , Hertter M. , Sellars C. 
Published: September 2022

Abstract
The newly designed abradable coatings are usually validated by rig tests, where samples are rubbed by the contact of a dummy blade with given running speed and incursion rate, simulating actual working conditions in an aircraft engine. The aim of this work was to develop a model of abradable coating rig tests, allowing extensive studies on the influence of coating properties and test conditions on the thermal behaviour of the system. The proposed model includes several steps implementing different numerical tools. Firstly, a relevant structural description of an abradable coating is obtained from micrographs, using an original image analysis route. FE (Finite Element) calculations based on this description allow then to estimate the coefficients of an anisotropic elastic law of mechanical behaviour. Furthermore, a plasticity law is deduced from a FE simulation of the material HR15Y hardness. These parameters are used as input of a FE simulation of a single blade-to-coating rubbing hit, resulting in calculated stresses and temperatures. Finally a global approach of the complete abradability test, based on the results obtained from the simulation of a single hit and on various assumptions, provides predictions of the blade and coating temperature variations versus time during a complete abradability test.