The FeCr-Based Coating by On-Site Twin-Wire Arc Spraying for Proactive Maintenance of Power Plant Components

In this study, Ni-5wt.%Al coating was fabricated on the 6061-T6 aluminum alloy substrate by twin-wire arc spraying technology. Through different heat treatment process, effect of microstructure and phase structure was studied with different temperature and time. Interface reaction mechanism of alloy coating/substrate and diffusion behavior of elements was discussed. Heat treatment was carried out at 400°C，480°C，550°C and respective for 4h, 24h, 48h. The XRD , SEM and EDS results showed that main phases of Ni-5wt.%Al original coating were composed of Ni solid solution, in addition to a small amount of Al2O3, NiO and Al4Ni3. Phase composition has basically not changed, interface of the coating/substrate occurred diffusion, which was controlled by the diffusion of Al atoms. Intermetallic compounds of NiAl3 and Ni2Al3 were formed in interface of coating/substrate, and interface diffusion area gradually was thickened.

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CFD Study of Particle and Compressible Flow Interaction for a Twin Wire Arc Spraying System

Volume 7: Fluids Engineering ◽

10.1115/imece2019-10101 ◽

2019 ◽

Author(s):

Raymond Faull ◽

Nicole Wagner ◽

Kevin Anderson

Keyword(s):

Plasma Spraying ◽

Gas Flow ◽

Particle Trajectory ◽

Flow Direction ◽

Phase Changes ◽

Particle Flow ◽

Spray Angle ◽

Arc Spraying ◽

Twin Wire Arc Spraying ◽

Wire Arc Spraying

Abstract Plasma spraying is used in various industries for additive manufacturing applications to apply materials onto a workpiece. Such applications could be for the purpose of repair, protection against corrosion, wear-resistance, or enhancing surface properties. One plasma spraying method is the twin wire arc spraying (TWAS) process that utilizes two electrically conductive wires, across which an electric arc is generated at their meeting point. The molten droplets that are created are propelled by an atomizing gas towards a substrate on which the coating is deposited. The TWAS process offers low workpiece heating and high deposition rates at a lower cost compared to other plasma spraying techniques. As the spray angle for this technique is relatively large (15 degree half angle), particles are lost in the process, lowering the yield of deposited material. The motivation of this project was to constrict the particle flow and reduce the loss of particles that are ejected by the spraying torch. Torch nozzles were designed to help the particle trajectory match the axial flow direction of the atomizing gas flow. Simulations using ANSYS FLUENT Computational Fluid Dynamics (CFD) software was utilized to model both the atomizing gas flow and particle flow for a TWAS system. Various nozzle configurations with arc jet angles between 30–75 degrees showed only small effects on gas flow velocity and shape, with no significant variations in particle flow. These results indicate that nozzle configurations are only one factor in determining particle trajectory, and that phase changes and heat transfer need to be considered as well.

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Asymmetric Melting Behavior in Twin Wire Arc Spraying with Cored Wires

Journal of Thermal Spray Technology ◽

10.1007/s11666-008-9269-y ◽

2008 ◽

Vol 17 (5-6) ◽

pp. 974-982 ◽

Cited By ~ 10

Author(s):

W. Tillmann ◽

E. Vogli ◽

M. Abdulgader

Keyword(s):

Melting Behavior ◽

Arc Spraying ◽

Twin Wire Arc Spraying ◽

Wire Arc Spraying ◽

Cored Wires

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Multiphysics Modeling and Simulation of an Arc-Jet Sprayer

10.1115/fedsm2021-65319 ◽

2021 ◽

Author(s):

Juan J. Campos Manzo ◽

Nicole Wagner ◽

Kevin R. Anderson

Keyword(s):

Heat Transfer ◽

Surface Temperature ◽

Substrate Surface ◽

Arc Spraying ◽

Process Conditions ◽

Transfer Model ◽

Ansys Fluent ◽

Numerical Heat Transfer ◽

Twin Wire Arc Spraying ◽

Wire Arc Spraying

Abstract Twin wire arc spraying (TWAS) is a plasma spraying process that offers low workpiece heating and high deposition rates at a lower cost. Variations in TWAS process conditions cause the substrate temperature to fluctuate and even melt. Therefore, the motivation of this project was to simulate the heat transfer from the TWAS torch to the substrate during spraying and layer formation of a coating. Simulations using ANSYS FLUENT Computational Fluid Dynamics (CFD) software were used to model the heat transfer in a TWAS system. The results of this paper are meant to augment and improve the database of TWAS technology. A CFD numerical heat transfer model is presented that was used to investigate the substrate surface temperature during the TWAS process. The results for the different pressure models showed that for a 3 second simulation, substrate surface temperatures increased as nozzle inlet pressure was decreased. For the upper and lower bound pressures of 75 psia and 29 psia, substrate surface temperature resulted in 946 °C and 1010 °C, respectively.

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Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying

Advances in Materials Science and Engineering ◽

10.1155/2014/836739 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Ana Arizmendi-Morquecho ◽

Araceli Campa-Castilla ◽

C. Leyva-Porras ◽

Josué Almicar Aguilar Martinez ◽

Gregorio Vargas Gutiérrez ◽

...

Keyword(s):

Electron Microscopy ◽

Boron Carbide ◽

Amorphous Matrix ◽

Steel Substrate ◽

Microstructural Characterization ◽

Arc Spraying ◽

Tungsten Carbides ◽

Wear Properties ◽

Twin Wire Arc Spraying ◽

Wire Arc Spraying

Twin wire arc spraying (TWAS) was used to produce an amorphous crystalline Fe-based coating on AISI 1018 steel substrate using a commercial powder (140MXC) in order to improve microhardness and wear properties. The microstructures of coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) as well as the powder precursor. Analysis in the coating showed the formation of an amorphous matrix with boron and tungsten carbides randomly dispersed. At high amplifications were identified boron carbides at interface boron carbide/amorphous matrix by TEM. This kind of carbides growth can be attributed to partial crystallization by heterogeneous nucleation. These interfaces have not been reported in the literature by thermal spraying process. The measurements of average microhardness on amorphous matrix and boron carbides were 9.1 and 23.85 GPa, respectively. By contrast, the microhardness values of unmelted boron carbide in the amorphous phase were higher than in the substrate, approaching 2.14 GPa. The relative wear resistance of coating was 5.6 times that of substrate. These results indicate that the twin wire arc spraying is a promising technique to prepare amorphous crystalline coatings.

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