The Experts below are selected from a list of 72738 Experts worldwide ranked by ideXlab platform
Liang Wang - One of the best experts on this subject based on the ideXlab platform.
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Design and optimization of Coating Structure for plasma sprayed self-healing MgO Coating via finite element method
Ceramics International, 2021Co-Authors: Mingxiang Zhuang, Jianhui Yuan, Huanyu Zhang, Jiajia Zhang, Bin Huang, Liang WangAbstract:Abstract The necessary conditions for fabricating plasma sprayed self-healing MgO Coating with excellent performance is to find an optimized Coating Structure with suitable thickness of each layer, self-healing agent content and low residual stress. This paper discusses the design and optimization of a suitable Coating Structure for the self-healing MgO Coating prepared by atmospheric plasma spraying (APS) using the finite element method (FEM). Through the stress analysis of the special points of the Coating and interface, a suitable Coating Structure is designed. The optimization of the Coating Structure mainly includes the thickness of the Coating, the analysis of the composition of the Coating and the analysis of the effect of convective heat transfer coefficient (CHTC) on the residual stress of the Coating. The failure modes are predicted. The spray thickness of each layer and the fabrication method in the Coating cooling process are optimized.
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Design and optimization of Coating Structure for the thermal barrier Coatings fabricated by atmospheric plasma spraying via finite element method
Journal of Asian Ceramic Societies, 2014Co-Authors: Liang Wang, X.h. Zhong, Y.x. Zhao, Shunyan Tao, W. Zhang, Ying Wang, X.g. SunAbstract:Abstract The first prerequisite for fabricating the thermal barrier Coatings (TBCs) with excellent performance is to find an optimized Coating Structure with high thermal insulation effect and low residual stress. This paper discusses the design and optimization of a suitable Coating Structure for the TBCs prepared by atmospheric plasma spraying (APS) using the finite element method. The design and optimization processes comply with the rules step by step, as the Structure develops from a simple to a complex one. The research results indicate that the suitable thicknesses of the bond-Coating and top-Coating are 60–120 μm and 300–420 μm, respectively, for the single ceramic layer YSZ/NiCoCrAlY APS-TBC. The embedded interlayer (50 wt.%YSZ + 50 wt.%NiCoCrAlY) will further reduce the residual stress without sacrificing the thermal insulation effect. The double ceramic layer was further considered which was based on the single ceramic layer TBC. The embedded interlayer and the upper additional ceramic layer will have a best match between the low residual stress and high thermal insulation effect. Finally, the optimized Coating Structure was obtained, i.e., the La 2 Ce 2 O 7 (LC)/YSZ/Interlayer/NiCoCrAlY Coating Structure with appropriate layer thickness is the best choice. The effective thermal conductivity of this optimized LC/YSZ/IL/BL TBC is 13.2% lower than that of the typical single ceramic layer YSZ/BL TBC.
Ghislain Montavon - One of the best experts on this subject based on the ideXlab platform.
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Suspension plasma spraying of zirconia Coatings : process and Coating Structure
2007Co-Authors: O. Tingaud, Jean François Coudert, Vincent Rat, Ghislain Montavon, Alain Denoirjean, Hélène Ageorges, Pierre Fauchais, R. Etchart-salas, Alain Grimaud, N. CaronAbstract:Suspension plasma spraying (SPS) permits to manufacture finely Structured Coatings (nano- or submicron-sized) Coatings. Compared to conventional plasma spraying, SPS exhibit several major differences: i) a more pronounced sensitivity to arc root fluctuations; ii) a shorter spray distance; iii) a higher thermal flux transmitted from the plasma flow to the substrate. Several operating parameters play relevant roles in the suspension processing and the Coating architecture.
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Suspension Plasma Spraying of Alumina Coatings: Process and Coating Structure
2007Co-Authors: Jean François Coudert, Vincent Rat, Alain Denoirjean, Hélène Ageorges, Pierre Fauchais, Ghislain MontavonAbstract:Summary form only given. Due to the large volume fraction of the internal interfaces, Coatings Structured at the nanoscale should exhibit better properties than conventional Coatings Structured at the microscale. However, when processing by thermal plasmas such feedstock, several questions arise: (i) how feeding the plasma jet with nanosized powders? (ii) how keeping their nanoStructured Structures when melting them? (iii) how controlling the growth of Coating's grain? Suspension plasma spraying (SPS) appears as a technology permitting to circumvent those difficulties. It consists in mechanically injecting within the plasma flow a liquid suspension of particles of average diameter varying between 0.1 and 1 mum through an injector of diameter in the order of one hundred micrometers. Upon penetration within the DC plasma jet, two phenomena occur sequentially: droplet fragmentation and then evaporation (lasting, in average, two orders of magnitude longer than fragmentation). Particles are then processed by the plasma flow prior their impact, spreading and solidification upon the surface to be covered. Compared to plasma spraying of micron-sized particles, SPS exhibit several major differences: (i) a more pronounced sensitivity to arc root fluctuations requiring to adapt operating parameters in order to operate the spray gun in its take over mode unless to have inhomogeneous process of the suspension by the plasma: (ii) a shorter spray distance since small particles decelerate faster than bigger ones; (iii) a higher thermal flux transmitted from the plasma flow to the substrate, between 5 to 10 times higher than the heat flux transmitted in conventional plasma spraying. In consequence, Coatings manufactured by SPS differ from conventional Coatings by: (i) a more pronounced sensitivity to the particle size distribution: narrow-sized ones are absolutely required to produce dense layers; (ii) lamella characteristic dimensions smaller than the ones encountered in conventio-\nnal plasma spraying (with lower flattening ratio due to lower particle Reynolds numbers upon impact) with almost no peripheral splashing (due to lower particle adjusted Sommerfeld numbers upon impact); (iii) lower residual stress levels within lamellae which limit the development of intralamellar cracks; (iv) a denser Structure with almost no pore connectivity. This paper aims at presenting the SPS of alumina Coatings in terms of: (i) suspension characteristics on the Coating architecture; (ii) process optimization, emphasizing the predominant role of the arc root fluctuations on the Coating architecture; (iii) resulting Coating architectures, in particular in terms of their pore network architecture.
Junichi Sakai - One of the best experts on this subject based on the ideXlab platform.
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effect of curing temperature on Coating Structure and corrosion resistance of ammonium zirconium carbonate on galvanized steel surface
Surface & Coatings Technology, 2013Co-Authors: Ryosuke Sako, Junichi SakaiAbstract:Abstract The effect of curing temperature on the Structure and corrosion resistance of an ammonium zirconium carbonate (AZC) Coating on galvanized steel was investigated as an alternative to chromate. The corrosion resistance of the AZC Coating was excellent when cured at 80 °C, but it decreased with an increase in the curing temperature; it was significantly inferior at curing temperatures over 160 °C. Two endothermic events were observed at 115 °C and 155 °C. The event at 115 °C resulted from the elimination of the water molecule coordinated to the zirconium atom, and the event at 155 °C resulted from the dehydration condensation of the hydroxide group involved in the bonds between zirconium, i.e., conversion of an ol-bridge to an oxo-bridge. Furthermore, it was observed that the cathode current of the Coating plate cured at 160 °C or 200 °C, whose corrosion resistance was inferior to that at 80 °C or 120 °C in the salt spray test, increased. It is supposed that the dehydration occurring at 155 °C promoted shrinkage of the Coating volume, which in turn caused the development of fissures on the Coating surface. The fissures on the Coating surface reduced the corrosion resistance significantly due to the increase in cathode current, which signifies the reduction of dissolved oxygen at the Coating/metal interface.
Mingxiang Zhuang - One of the best experts on this subject based on the ideXlab platform.
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Design and optimization of Coating Structure for plasma sprayed self-healing MgO Coating via finite element method
Ceramics International, 2021Co-Authors: Mingxiang Zhuang, Jianhui Yuan, Huanyu Zhang, Jiajia Zhang, Bin Huang, Liang WangAbstract:Abstract The necessary conditions for fabricating plasma sprayed self-healing MgO Coating with excellent performance is to find an optimized Coating Structure with suitable thickness of each layer, self-healing agent content and low residual stress. This paper discusses the design and optimization of a suitable Coating Structure for the self-healing MgO Coating prepared by atmospheric plasma spraying (APS) using the finite element method (FEM). Through the stress analysis of the special points of the Coating and interface, a suitable Coating Structure is designed. The optimization of the Coating Structure mainly includes the thickness of the Coating, the analysis of the composition of the Coating and the analysis of the effect of convective heat transfer coefficient (CHTC) on the residual stress of the Coating. The failure modes are predicted. The spray thickness of each layer and the fabrication method in the Coating cooling process are optimized.
Jean François Coudert - One of the best experts on this subject based on the ideXlab platform.
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Suspension plasma spraying of zirconia Coatings : process and Coating Structure
2007Co-Authors: O. Tingaud, Jean François Coudert, Vincent Rat, Ghislain Montavon, Alain Denoirjean, Hélène Ageorges, Pierre Fauchais, R. Etchart-salas, Alain Grimaud, N. CaronAbstract:Suspension plasma spraying (SPS) permits to manufacture finely Structured Coatings (nano- or submicron-sized) Coatings. Compared to conventional plasma spraying, SPS exhibit several major differences: i) a more pronounced sensitivity to arc root fluctuations; ii) a shorter spray distance; iii) a higher thermal flux transmitted from the plasma flow to the substrate. Several operating parameters play relevant roles in the suspension processing and the Coating architecture.
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Suspension Plasma Spraying of Alumina Coatings: Process and Coating Structure
2007Co-Authors: Jean François Coudert, Vincent Rat, Alain Denoirjean, Hélène Ageorges, Pierre Fauchais, Ghislain MontavonAbstract:Summary form only given. Due to the large volume fraction of the internal interfaces, Coatings Structured at the nanoscale should exhibit better properties than conventional Coatings Structured at the microscale. However, when processing by thermal plasmas such feedstock, several questions arise: (i) how feeding the plasma jet with nanosized powders? (ii) how keeping their nanoStructured Structures when melting them? (iii) how controlling the growth of Coating's grain? Suspension plasma spraying (SPS) appears as a technology permitting to circumvent those difficulties. It consists in mechanically injecting within the plasma flow a liquid suspension of particles of average diameter varying between 0.1 and 1 mum through an injector of diameter in the order of one hundred micrometers. Upon penetration within the DC plasma jet, two phenomena occur sequentially: droplet fragmentation and then evaporation (lasting, in average, two orders of magnitude longer than fragmentation). Particles are then processed by the plasma flow prior their impact, spreading and solidification upon the surface to be covered. Compared to plasma spraying of micron-sized particles, SPS exhibit several major differences: (i) a more pronounced sensitivity to arc root fluctuations requiring to adapt operating parameters in order to operate the spray gun in its take over mode unless to have inhomogeneous process of the suspension by the plasma: (ii) a shorter spray distance since small particles decelerate faster than bigger ones; (iii) a higher thermal flux transmitted from the plasma flow to the substrate, between 5 to 10 times higher than the heat flux transmitted in conventional plasma spraying. In consequence, Coatings manufactured by SPS differ from conventional Coatings by: (i) a more pronounced sensitivity to the particle size distribution: narrow-sized ones are absolutely required to produce dense layers; (ii) lamella characteristic dimensions smaller than the ones encountered in conventio-\nnal plasma spraying (with lower flattening ratio due to lower particle Reynolds numbers upon impact) with almost no peripheral splashing (due to lower particle adjusted Sommerfeld numbers upon impact); (iii) lower residual stress levels within lamellae which limit the development of intralamellar cracks; (iv) a denser Structure with almost no pore connectivity. This paper aims at presenting the SPS of alumina Coatings in terms of: (i) suspension characteristics on the Coating architecture; (ii) process optimization, emphasizing the predominant role of the arc root fluctuations on the Coating architecture; (iii) resulting Coating architectures, in particular in terms of their pore network architecture.