bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastoplastic Characterization of Thermal Spray Coatings using Instrumented Indentation
Authors: Gouldstone Andrew , Prchlik Lubos , Kulkarni Anand , Sampath Sanjay 
Published: July 2022

Abstract
Instrumented indentation is well-suited as a technique for probing mechanical behaviour of coatings; it requires minimal specimen preparation, can be performed multiple times on a single specimen, and can measure behaviour over various length scales, by recourse to appropriate indenter tip selection. However, the complex nature of the deformation fields under the tip, coupled with complex (e.g. anisotropy, nonlinearity) coating properties necessitates robust means of interpretation in order to extract stress-strain behaviour. Here we present a simple method, based on empirical work by Tabor, for converting coating indentation force-depth data to stress-strain curves. Using this method, results of indentation can thus be used to quantify mechanical behaviour of coatings deposited by different processes, and subjected to post-processing treatments, providing a powerful supplement to microstructural characterization. In addition, we show how anisotropic elasticity of coatings, measured via indentation, can qualitatively identify the existence of different microstructual features. Finally, we explore subsurface strain mapping as a technique to quantitatively compare elastoplastic behaviour of coatings to bulk, isotropic materials.
Study of the Influence of Microstructure on Electric Properties of Plasma-Sprayed Alumina Coatings using the Scanning Electron Microscope Mirror Effect (SEMME) Method
Authors: Beauvais S. , Guipont V. , Jeandin M. , Juve D. , Treheux D. , Robisson A. , Saenger R. 
Published: July 2022

Abstract
Pure alumina coating obtained by thermal spraying can find applications as electrical insulating layer. Thermally-sprayed ceramic coatings exhibit a complex lamellar structure with a network of interconnected pores, inter-lamellar and intra-lamellar cracks. In this work, the influence of the microstructure on electric properties for plasma-sprayed alumina coatings was investigated. Coatings have been sprayed with different pressures and gases using a CAPS (‘Controlled Atmosphere Plasma Spraying’) as well as different alumina feedstock powders. Detailed quantitative image analysis of cross-section views allowed to select six microstructures with different porosity levels and cracks orientation distributions. In order to assess the behaviour of the electrical insulation and the influence of local defects on electric properties, the so-called Scanning Electron Microscope Mirror Effect (SEMME) method has been applied on outer surfaces and on cross-sections of the different selected alumina coatings. This method, originally developed to study the ability of a bulk insulating material in trapping of charges from an electron beam irradiation in a SEM, revealed to be successfully feasible for porous materials such as thermally-sprayed ceramic coatings. It has been shown that cracks orientation modified both propagation and trapping of charges and therefore the electric properties of plasma-sprayed alumina coatings.
Measurement of a Low Power Plasma Jet by the Enthalpy Probe
Authors: Gao Yang , An Lian-Tong , Sun Cheng-Qi , Yan Zhi-Jun 
Published: July 2022

Abstract
The effects of the plasma gas composition (Ar-N2, Ar-H2), arc current and voltage on the temperature and velocity of a low power (5 kW) plasma torch in the arc field free region have been investigated using an enthalpy probe. Coatings of Al2O3-13TiO2 were deposited under different conditions. The results show that in the Ar-N2 plasma, the enthalpy, temperature and velocity change little with arc current and voltage when regulating the nitrogen proportion in the plasma gas, and the hardness of the resulting coatings is 800-900 HV. For Ar-H2 plasma, however, increasing the H2 content in the gas mixture remarkably enhanced the velocity and heat transfer of the plasma jet with the result that the coatings showed the high hardness up to 1200 HV.
Nanostructured Aluminum Coatings Produced Using Cold Spraying Technology
Authors: Mondoux J. , Jodoin B. , Ajdelsztajn L. , Schoenung J.M. , Kim G.E. 
Published: July 2022

Abstract
A mathematical model was developed and used to design and optimize a supersonic nozzle for a cold spray system. The objective was to spray 20 micron-size aluminum particles. Conventional and agglomerated nanostructured powders were used and successfully sprayed using a radial injection port. The microstructure of the coatings revealed that the nanocrystalline structure is preserved. An increase of 100% of the coating hardness was found for nanostructured coatings compared to conventional coatings. Further work needs to be done to improve the porosity of the coatings by changing some of the process parameter.
Maximization of Silica Loading in Ball-Milled Composite Powders for HVOF-Sprayed Multi-scale Polymer/Silica Composite Coatings
Authors: Saenz A. , Knight R. , Twardowski T. 
Published: July 2022

Abstract
The high velocity oxy-fuel (HVOF) combustion spray technique has been shown previously to be an excellent solution for depositing crystalline matrix nano-reinforced polymer coatings. Dense polymer coatings can be produced by controlling both the particle dwell time in the HVOF jet and through substrate thermal management. In composite materials, it is often desirable to incorporate the maximum amount of reinforcing material into the polymer matrix to achieve optimum mechanical properties. The experiments described here were performed to determine the maximum amount of different scales of silica particles that could be incorporated into a nylon 11 matrix and the time required to do so. Ashing results indicated a maximum amount of silica that can be incorporated. Also, the maximum level of silica incorporation occurs in a shorter time than previously believed. Microscopy, however, indicated that other physical changes continued to occur within the powders when ball milling was allowed to continue beyond this time.
Erosion and Erosion-Corrosion Properties of HVOF Sprayed Tungsten Carbide (WC) Coatings with High Alloy Binders
Authors: Berget J. , Rogne T. 
Published: July 2022

Abstract
This paper describes results from investigations of tungsten carbide (WC) coatings with high alloy binders. Experimental powders were manufactured by agglomeration/sintering using pre-alloyed metal particles together with WC particles. Coatings were sprayed by the HVOF process and investigated with respect to microstructure, hardness, erosion and erosion-corrosion. For comparison coatings from commercial powder materials were sprayed and investigated. This and previous work has demonstrated the importance of having a corrosion resistant binder. A corrosion resistant binder is of major importance for constructions where maintenance is difficult for instance in constructions for oil and gas production from wells at large depths in the North Sea. Improved coating quality will lead to increased life time for coated components, improved safety conditions, fewer shut-downs and large reductions in maintenance costs.
Investigations of Corrosion Properties of Different Ceramic-Metallic Coatings Sprayed by the HVOF Process
Authors: Rogne T. , Berget J. 
Published: July 2022

Abstract
In corrosive media the wear resistance of ceramic-metallic coatings depends on the corrosion resistance of the metallic binder. Other factors influencing the coating deterioration are the corrosivity of the media and any galvanic interaction from the surrounding material. The corrosion resistance of the metallic binder should be comparable to the material of the rest of the system. This is especially important when the surrounding materials are corrosion resistant alloys such as stainless steels, where the coatings otherwise will act as an anode. This paper summarises results from corrosion tests of different ceramic-metallic coatings sprayed by the HVOF process. The corrosion properties of the coatings have been compared with results from corresponding tests obtained for stainless steel and some nickel based alloys. The corrosion compatibility and risk of galvanic corrosion is discussed.
Corrosion Resistance of Fe-Cr-Mo-(C,B,P) Amorphous Coatings Thermal Sprayed by HVOF and APS Processes
Authors: Otsubo F. , Shimoda A. , Era H. , Kishitake K. 
Published: July 2022

Abstract
Two kinds of Fe-16Cr-30Mo-(C,B,P) alloy powders of different composition were thermal sprayed onto mild steel using HVOF and APS processes. Perfect amorphous coating was formed by HVOF and APS processes in both powders. The corrosion potential of the amorphous coatings sprayed by HVOF process was higher and the passive current density was lower than that of the amorphous coatings sprayed by APS process in 1N HCl solution. The coatings of perfect amorphous phase were little corroded after one week immersion tests and the corrosion rates of the amorphous coatings showed a fairly less value of 0.03 mm/y compared with Inconel 625 plate in 5N HCl solution at room temperature.
Effect of Coating Thickness and Sealants on the Steam Oxidation Resistance of APS Ni-Cr Coatings
Authors: Sundararajan T. , Haruyama H. , Kuroda S. , Abe F. 
Published: July 2022

Abstract
In our earlier studies we reported the excellent steam oxidation resistance of 50Ni-50Cr coatings produced by high velocity oxyfuel (HVOF) spray process. The coating produced by atmospheric plasma spray (APS) for the thickness of 40 µm yielded the scale incorporation into the coating structure on the steam oxidation due to its porous structure compared to HVOF process. The steam could penetrate into the pores and resulted in the scale initiation at the coating-substrate interface. To improve the steam oxidation resistance of the coating, thick coatings (~450 µm) of 50Ni-50Cr with sealant layer were tested in the steam. The sealant layer was applied to fill the pores produced by the APS process. The results showed that the thick coating of 50Ni-50Cr with sealant was able to protect against the steam oxidation till 3000 hours of tested duration.
Metallographic Evaluation and Process Correlation of Thermally Sprayed Coatings
Authors: Lima Carlos Roberto Camello , Camargo Flávio , de Lima Carmo Roberto Pelliciari 
Published: July 2022

Abstract
Thermal sprayed coatings are widely used for industrial applications. One of the main characteristics that have to be evaluated in a coating is its microstructure that finally determines the coating performance. Several techniques and processes are available for coatings deposition and new materials have been incorporated in the long list of the available ones. Therefore, since microstructure is a key factor to be evaluated, its preparation has to follow some rules in order to inhibit incorrect statements that can arise from wrong interpretation of an incorrect sample preparation. In this work, a series of distinctive materials are thermally sprayed onto low carbon steel substrates. The metallographic preparation of samples for the different coatings is presented and the effects of correct or wrong sample preparation are discussed and correlated to coating microstructure and process characteristics. The coatings were applied by Air Plasma Spray (APS) and Electric Arc Spray.
Prediction of Plasma Sprayed Coating Properties by the Use of Neural Networks
Authors: Lugscheider E. , Seemann K. 
Published: July 2022

Abstract
The number of parameters and noise factors that influence the plasma spraying process is huge, with over 200 known. Today, only a few parameters such as gas flow rate, current, voltage, spraying distance and substrate roughness can be controlled. In recent years, several particle diagnostic systems have been developed, which give the chance to control processes much better than at present. These techniques are now close to being introduced in industrial applications. In addition to the in-flight particle properties, the surface temperature of the substrate has a large influence on the coating quality. Statistical methods are widely used to quantify the influences of the particle and substrate characteristics. Neural networks provide a greater capability to analyse particle characteristics and substrate temperature data for coating quality control. In this work, the analysis of comprehensive process data and coating characteristics using neural networks is investigated and compared to established design of experiments (DOE) statistical methods.
Tribological Behavior of HVOF-Sprayed Cr3C2-NiCr and TiC-based Coatings under High- Temperature Dry Sliding Conditions
Authors: Berger L.-M. , Woydt M. , Zimmermann S. , Keller H. , Schwier G. , Enžl R. , Thiele S. 
Published: July 2022

Abstract
In the current study, the tribological properties of TiC-based coatings paired with polycrystalline alumina under unlubricated sliding conditions were investigated in order to demonstrate the technological and engineering potential of such coatings. (Ti, Mo)(C, N)-Co coatings were prepared from an agglomerated and sintered spray powder by HVOF spraying using JP-5000 equipment. Cr3C2-NiCr coatings were studied for comparison. Sliding wear tests were performed over the temperature range from 23°C to 800°C with sliding speeds in the range 0.3-3 m/s, a wear distance of 5000 m and a normal force of 10 N. Wear rates of coatings and sintered alumina counterparts were measured separately. Compared with Cr3C2-NiCr coatings, (Ti, Mo)(C,N)-Co coatings showed significantly lower total wear rates, corresponding to those found in the region of mixed/boundary lubrication. With few exceptions, the coefficients of friction were found to be lower for (Ti, Mo)(C,N)-Co coatings than for Cr3C2-NiCr coatings. After tests were performed, the coating microstructures were studied by optical microscopy and SEM. The oxide scales formed on the coating surfaces were investigated by SEM and X-ray diffraction. Comparison of the total wear rates of the couples consisting of sintered alumina and a (Ti, Mo)(C,N)-Co coating with those of other alumina-ceramic and hardmetal-hardmetal tribological systems demonstrates the immense potential of TiC-based coatings for sliding wear applications.
Optimization of Wear Protective Coatings for Heat Transferring Components
Authors: Wielage B. , Reisel G. , Wank A. , Gross U. , Barth G. 
Published: July 2022

Abstract
The laser-flash method is used to determine the thermal diffusivity of HVOF sprayed WC-Co(Cr) and Cr3C2-Ni20Cr as well as APS sprayed Cr2O3 and electroplated hard chromium coatings in the temperature range between RT and 600°C. Additionally bond and/or corrosion protective coatings like Ni5Al, Ni20Cr and 316L are characterized taking into account the different manufacturing methods twin wire arc spraying, HVCW and HVOF. With respect to the application example of drying rollers in paper industries the Taber-Abraser wear test is applied to evaluate the wear resistance. Finally the coatings are characterized concerning their corrosion resistance by salt fog test and by exposure to humid SO2 environment. For WC-CoCr feedstock the effect of carbide size and micro hardness on thermal, wear and corrosion properties are studied. WC-CoCr coatings with maximum micro hardness and fine carbides show the best thermal conductivity. The use of coarse carbide feedstock permits manufacturing of coatings with the highest resistance against dry abrasive wear, but the protective function depends severely on the processing conditions.
Finely Structured Ceramic Coatings Elaborated by Liquid Suspension Injection in a DC Plasma Jet
Authors: Delbos C. , Fazilleau J. , Rat V. , Coudert J.F. , Fauchais P. , Bianchi L. 
Published: July 2022

Abstract
This paper describes a study of a plasma spray process to deposit ceramic coatings with finer structures than those that can be produced by conventional DC plasma spraying. The structures are similar to those produced by plasma-enhanced chemical vapor deposition (PECVD), but with a very fast coating rate and the ability to produce a wide range of thicknesses (1 &lt; e &lt; 100 µm). The process involves injecting a ceramic suspension containing submicronic ceramic particles into a DC plasma jet. The goal is to develop the process so that it can be used for the production of such coatings as yttria stabilized zirconia (YSZ), Ni-YSZ, or perovskite (for solid oxide fuel cells) or YSZ, Al2O3-YSZ, or Pyrochlore (for thermal barrier applications). The research stage described in this paper is related to the study of the growth of YSZ coatings, to calculations of the dynamic and thermal plasma-particle transfers, linked to the effect on particle flattening of the various spray parameters (arc current intensity, particle collection distance, substrate temperature, plasma gas composition, and so on). It also describes the achievement of a multi layered coating of YSZ and alumina.
Durability of the Zirconia based Coatings in Contact with Manganese Oxide at 1273 K
Authors: Gao Y. , Shun C.Q. 
Published: July 2022

Abstract
The phase transformation and reaction of ZrO2-CaO- ZrSiO4 and ZrO2-Y2O3-ZrSiO4 coatings with manganese oxide at 1273 K were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). SiO2 phase formed in the coatings, which was from the ZrSiO4 decomposed and easy react with manganese oxide or CaO. SiO2 has precedence over react with CaO than manganese oxides for ZrO2-CaO-ZrSiO4 coatings, and which result in to promote t-m phase transformation. On the contrary, the reaction between SiO2 and MnO is primary for the ZrO2-Y2O3-ZrSiO4 coatings and result in the damage or exfoliation on the surface of the coatings.
Plasma Reaction Synthesis of Agglomerated Oxide Powders by Axial Injection Torch
Authors: Mager J. , Cannon W.R. , Kear B.H. 
Published: July 2022

Abstract
Several compositions of agglomerated ZrO2(Y2O3), Al2O3 and MgAl2O4 powders were plasma sprayed through an axial injection torch into a water quenching chamber in order to obtain a fully melted and homogenized, metastable particle nanostructure. This metastable extended solid solution morphology allows the powder to be subsequently heat treated and superplastically formed into ceramic parts with potentially excellent optical and mechanical properties. Light microscopy, SEM and XRD analyses were used to evaluate the melt-quenched powder properties, and some comparison was made to previous work performed with traditional radial injection plasma torches. Thick build-ups were also sprayed from the melt-quenched powders to test their ability to superplastically flow. Results showed that during a single processing through the torch the axial injection equipment produced powders with a significantly higher fraction of fully homogenized powders than previously attainable. Homogenization of powders comprised of a larger particle size range was also achieved.
Deposition Rate Increase in APS Processes by Means of Multiple Injection Ports
Authors: Choquet I. , Nylén P. , Wigren J. 
Published: July 2022

Abstract
This paper presents a method to increase deposition rate of thermal plasma spray operations through the use of multiple injection ports. Numerical simulations indeed revealed a major energy loss in the process when using only one port. The influence of the carrier gas and the particle stream on the heat flow coming from the plasma torch was found very local and small compared to the total amount of energy. To take as much as possible advantage of the energy available in the plume, we thus propose to use a multiple number of injectors around the flame. Computational simulations are carried out to estimate the feasibility. They are based on the 3D Navier-Stokes equations coupled with a turbulence model. The gases (plasma gas, surrounding air and carrier gas) are supposed to be in local thermal and chemical equilibrium and loading effects are accounted for. The numerical results are supplemented by experimental results showing that multiple injectors can significantly increase deposition rate while preserving or even slightly improving the deposition efficiency. Characterisation of the microstructure, evaluated for all tests, is similar and no obvious differences can be detected apart from the porosity. This method thus results in a substantial reduction of the production cost.
Measurements of Elastic-Plastic Anisotropic Properties of Thermally Sprayed Coatings Using Nano-Indenters and Inverse Analysis Technique
Authors: Nakamura Toshio , Gu Yu 
Published: July 2022

Abstract
Thermally sprayed coatings are often anisotropic due to their manufacturing processes. However, identification of anisotropic properties is very difficult not only because of such material systems but also their small scales. The present work present a new procedure based on nano-indentation technique and inverse analysis to characterize transversely isotropic elastic-plastic coatings. In particular, it uses Kalman filter, which processes the indentation measurements to extract unknown material parameters. This procedure employs load-penetration records of two indenters, spherical and Berkovich. An advantage of this method is that it requires minimum specimen preparations and the measurement procedure is straightforward. APS NiAl coating is indented and their records are used to estimate its anisotropic factors. The results support the effectiveness of the new procedure.
Modeling of Inductively Coupled Plasma Flows in a Reactor: Comparison with Experimental Results
Authors: Guénadou D. , Meillot E. 
Published: July 2022

Abstract
Inductive plasma torches are used in a wide range of applications such as spraying, waste destruction, powder treatment... In this kind of torch, the gas is heated to plasma state by ohmic heating due to the inductive current created by an electromagnetic field. Modeling this phenomenon has been studied by S. Xue and implemented in the commercial code FLUENT. This model is improved by introducing a turbulence model. To validate the model, experimental investigations are carried on. The gas temperature is measured using an enthalpy probe inside a tubular reactor at different positions. The measurements are compared with computational results and the accuracy is rather good.
Molecular Dynamics Simulation on Flattening Process of a High-Temperature and High-Speed Droplet
Authors: Shimizu J. , Ohmura E. , Kobayashi Y. , Kiyoshima S. , Eda H. 
Published: July 2022

Abstract
In order to clarify the flattening process of the high-temperature and high-speed droplet due to its impact on the substrate in an atomic level, several three-dimensional molecular dynamics simulations were conducted. The droplet and the substrate were assumed to consist of pure aluminum, and Morse potential was postulated between a pair of aluminum atoms. By visualizing the analytical result, the processes of melting and solidification, temperature distribution, deformation velocity and shape of the droplet were clarified. As a result, following conclusions were obtained: (1) The transfer of the droplet atoms to the horizontal direction in flattening process increases in proportion to the horizontal distance from the central axis of the droplet. (2) The solidification of the droplet starts from the outside edge of the droplet, and finishes as the flattening ratio increases. Such solidification behavior is different from the results analyzed with a continuum model on the assumption that the flattening finishes when the half volume of the droplet solidifies.