The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
Bernard Normand - One of the best experts on this subject based on the ideXlab platform.
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relationships between nicrbsi particle characteristics and corresponding Coating properties using different thermal spraying processes
Surface & Coatings Technology, 2005Co-Authors: Marie-pierre Planche, Han Lin Liao, Bernard Normand, Christian CoddetAbstract:Because the microstructure and physical properties of a Thermally Sprayed Coating are determined by the dynamics of the particles interacting with the spray jet, different processes were tested in order to explore the effects of process variables to particle characteristics and to Coating quality. The NiCrBSi powder was Sprayed successively with plasma, flame and HVOF process. Standard parameters specified by previous researches were followed for this operation. The DPV 2000 measurement system was used to monitor particle characteristics during their flight into the spray. Then, the Coatings were realized at the position corresponding to the DPV measurements. The Coatings were characterized in term of microstructure and composition, hardness, Young modulus, porosity and oxide level. The results revealed significant modifications in Coating properties depending on the used spray process. Comparing the particle characteristics obtained successively with the different processes allows to better understand the properties of the formed Coatings and to investigate the causes of a Coating quality changes. Differences were interpreted based on in-flight diagnostic results.
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electrochemical impedance spectroscopy and dielectric properties of polymer application to peek Thermally Sprayed Coating
Electrochimica Acta, 2004Co-Authors: Han Lin Liao, Bernard Normand, H Takenouti, M Keddam, G Monteil, Christian CoddetAbstract:Poly(ether ether ketone) (PEEK) Thermally Sprayed Coatings find more and more applications, and ensure often the protective effect of substrate metals when the coated material is exposed to an aggressive medium. This Coating exhibits extremely high impedance, and the impedance measurements of coated specimen were impossible to perform several years ago. Therefore, it was unable to evaluate quantitatively the Coating protective performance by an electrochemical impedance method. Such measurements were realized, in this paper, with a recent device, and the impedance behaviour observed was interpreted in terms of dielectric relaxation after extracting the frequency dependent capacitance from the impedance spectra. It was found that the water uptake in PEEK Coating is particularly low, ca. 1% and no interaction with absorbed water molecules and polymer matrix was detected. This result verifies therefore exceptionally high performance behaviour of PEEK Thermally Sprayed Coating in an aqueous medium. The impedance measurements may therefore be used to evaluate accurately the corrosion protective effect of such a Coating during development for new applications, and also to optimize the deposition conditions.
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interlamellar boundary characterization in ni based alloy Thermally Sprayed Coating
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: Regine Molins, Bernard Normand, G Rannou, B Hannoyer, Han Lin LiaoAbstract:The use of thermal spraying process for corrosion protection requires a high level of knowledge concerning the material modifications during Coating deposition. The effect of the high velocity oxygen fuel process on inconel 718 Thermally Sprayed Coating microstructure was studied by XRD, transmission electron microscopy and STEM analyses. Thermally Sprayed Coating exhibits an interlamellar oxidation related to the in-flight and cooling particles. The in-flight oxidation is characterised by a globular oxide which results from convective motion in the liquid phase of the molten particles before impact on the substrate. The oxide was identified as CrNbO4. The cooling step on the substrate induces a duplex oxide with an outer layer composed of columnar spinel oxide (Ni, Fe)Cr2O4 and an inner oxide corresponding to a nanocrystalline CrNbO4 oxide, which is related to the rapid cooling of the flattened particles. # 2002 Elsevier Science B.V. All rights reserved.
Han Lin Liao - One of the best experts on this subject based on the ideXlab platform.
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relationships between nicrbsi particle characteristics and corresponding Coating properties using different thermal spraying processes
Surface & Coatings Technology, 2005Co-Authors: Marie-pierre Planche, Han Lin Liao, Bernard Normand, Christian CoddetAbstract:Because the microstructure and physical properties of a Thermally Sprayed Coating are determined by the dynamics of the particles interacting with the spray jet, different processes were tested in order to explore the effects of process variables to particle characteristics and to Coating quality. The NiCrBSi powder was Sprayed successively with plasma, flame and HVOF process. Standard parameters specified by previous researches were followed for this operation. The DPV 2000 measurement system was used to monitor particle characteristics during their flight into the spray. Then, the Coatings were realized at the position corresponding to the DPV measurements. The Coatings were characterized in term of microstructure and composition, hardness, Young modulus, porosity and oxide level. The results revealed significant modifications in Coating properties depending on the used spray process. Comparing the particle characteristics obtained successively with the different processes allows to better understand the properties of the formed Coatings and to investigate the causes of a Coating quality changes. Differences were interpreted based on in-flight diagnostic results.
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electrochemical impedance spectroscopy and dielectric properties of polymer application to peek Thermally Sprayed Coating
Electrochimica Acta, 2004Co-Authors: Han Lin Liao, Bernard Normand, H Takenouti, M Keddam, G Monteil, Christian CoddetAbstract:Poly(ether ether ketone) (PEEK) Thermally Sprayed Coatings find more and more applications, and ensure often the protective effect of substrate metals when the coated material is exposed to an aggressive medium. This Coating exhibits extremely high impedance, and the impedance measurements of coated specimen were impossible to perform several years ago. Therefore, it was unable to evaluate quantitatively the Coating protective performance by an electrochemical impedance method. Such measurements were realized, in this paper, with a recent device, and the impedance behaviour observed was interpreted in terms of dielectric relaxation after extracting the frequency dependent capacitance from the impedance spectra. It was found that the water uptake in PEEK Coating is particularly low, ca. 1% and no interaction with absorbed water molecules and polymer matrix was detected. This result verifies therefore exceptionally high performance behaviour of PEEK Thermally Sprayed Coating in an aqueous medium. The impedance measurements may therefore be used to evaluate accurately the corrosion protective effect of such a Coating during development for new applications, and also to optimize the deposition conditions.
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interlamellar boundary characterization in ni based alloy Thermally Sprayed Coating
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: Regine Molins, Bernard Normand, G Rannou, B Hannoyer, Han Lin LiaoAbstract:The use of thermal spraying process for corrosion protection requires a high level of knowledge concerning the material modifications during Coating deposition. The effect of the high velocity oxygen fuel process on inconel 718 Thermally Sprayed Coating microstructure was studied by XRD, transmission electron microscopy and STEM analyses. Thermally Sprayed Coating exhibits an interlamellar oxidation related to the in-flight and cooling particles. The in-flight oxidation is characterised by a globular oxide which results from convective motion in the liquid phase of the molten particles before impact on the substrate. The oxide was identified as CrNbO4. The cooling step on the substrate induces a duplex oxide with an outer layer composed of columnar spinel oxide (Ni, Fe)Cr2O4 and an inner oxide corresponding to a nanocrystalline CrNbO4 oxide, which is related to the rapid cooling of the flattened particles. # 2002 Elsevier Science B.V. All rights reserved.
Christian Coddet - One of the best experts on this subject based on the ideXlab platform.
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relationships between nicrbsi particle characteristics and corresponding Coating properties using different thermal spraying processes
Surface & Coatings Technology, 2005Co-Authors: Marie-pierre Planche, Han Lin Liao, Bernard Normand, Christian CoddetAbstract:Because the microstructure and physical properties of a Thermally Sprayed Coating are determined by the dynamics of the particles interacting with the spray jet, different processes were tested in order to explore the effects of process variables to particle characteristics and to Coating quality. The NiCrBSi powder was Sprayed successively with plasma, flame and HVOF process. Standard parameters specified by previous researches were followed for this operation. The DPV 2000 measurement system was used to monitor particle characteristics during their flight into the spray. Then, the Coatings were realized at the position corresponding to the DPV measurements. The Coatings were characterized in term of microstructure and composition, hardness, Young modulus, porosity and oxide level. The results revealed significant modifications in Coating properties depending on the used spray process. Comparing the particle characteristics obtained successively with the different processes allows to better understand the properties of the formed Coatings and to investigate the causes of a Coating quality changes. Differences were interpreted based on in-flight diagnostic results.
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electrochemical impedance spectroscopy and dielectric properties of polymer application to peek Thermally Sprayed Coating
Electrochimica Acta, 2004Co-Authors: Han Lin Liao, Bernard Normand, H Takenouti, M Keddam, G Monteil, Christian CoddetAbstract:Poly(ether ether ketone) (PEEK) Thermally Sprayed Coatings find more and more applications, and ensure often the protective effect of substrate metals when the coated material is exposed to an aggressive medium. This Coating exhibits extremely high impedance, and the impedance measurements of coated specimen were impossible to perform several years ago. Therefore, it was unable to evaluate quantitatively the Coating protective performance by an electrochemical impedance method. Such measurements were realized, in this paper, with a recent device, and the impedance behaviour observed was interpreted in terms of dielectric relaxation after extracting the frequency dependent capacitance from the impedance spectra. It was found that the water uptake in PEEK Coating is particularly low, ca. 1% and no interaction with absorbed water molecules and polymer matrix was detected. This result verifies therefore exceptionally high performance behaviour of PEEK Thermally Sprayed Coating in an aqueous medium. The impedance measurements may therefore be used to evaluate accurately the corrosion protective effect of such a Coating during development for new applications, and also to optimize the deposition conditions.
P P Bandyopadhyay - One of the best experts on this subject based on the ideXlab platform.
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scratch resistance and damage mechanism of laser remelted Thermally Sprayed ceramic Coating
Surface & Coatings Technology, 2019Co-Authors: Biswajit Das, A K Nath, P P BandyopadhyayAbstract:Abstract Scratch resistance of plasma Sprayed and laser remelted alumina and chromia Coatings were assessed under constant and variable load. Failure load and cohesive strength of the Coatings increased up to 65% and 94%, respectively upon laser remelting. The scratch wear resistance increased up to 88%. This is attributed to an improvement in hardness, elastic modulus and indentation fracture toughness of the remelted Coatings. Upon laser remelting, lamellar microstructure of Thermally Sprayed Coating was transformed into a columnar microstructure. A phase change from γ-alumina to α-alumina also occurred. Principal mechanisms of failure of the Coatings were plastic deformation, tensile cracking, and spallation. In both types of Coatings, a subsurface crack was found to grow in a direction parallel to the scratch. Propagation of this crack to the surface produced spallation of the Coating. In the ball on disc test, the Coatings were found to fail by splat delamination and radial cracking. The wear coefficients of the laser remelted chromia and alumina Coating, respectively were 80% and 76% lower than those of the as-Sprayed Coatings.
Andre Mcdonald - One of the best experts on this subject based on the ideXlab platform.
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fabrication of Thermally Sprayed Coating systems for mitigation of ice accumulation in carbon steel pipes and prevention of pipe bursting
Surface & Coatings Technology, 2020Co-Authors: Milad Rezvani Rad, Morvarid Mohammadian Bajgiran, Christian Moreau, Andre McdonaldAbstract:Abstract Various multi-layered Thermally Sprayed Coatings were developed as heating systems for de-icing of the carbon steel pipes. Feasibility of fabrication of resistive heating Coatings, namely Ni 20Cr and Ni 50Cr deposited by flame spraying, air plasma spraying, and high-velocity oxygen fuel spraying processes, onto the carbon steel samples were studied. Given the electrical conductivity of carbon steel, alumina was deposited by flame spraying or suspension plasma spraying processes between the conductive resistive heating Coating and the substrate to prevent short circuiting and flow of electrons between these layers. Performance of the developed Coating systems was investigated by conducting heating tests in a cold room under different environmental conditions. It was found that the proposed heating system was able to generate the heat that was required to prevent formation and accumulation of ice, thus avoiding the detrimental effects such as bulging and ultimate bursting on the pipe of internal pressurization. Furthermore, it was also found that the selection of the thermal spraying process and spraying parameters can have a noticeable impact on the electrical performance. The obtained promising results indicate the potential utilization of these Coatings in industry on mass scale.
