共查询到20条相似文献,搜索用时 46 毫秒
1.
Yanguang Shan Thomas W. Coyle Javad Mostaghimi 《Journal of Thermal Spray Technology》2007,16(5-6):736-743
Solution precursor plasma spraying has been used to produce finely structured ceramic coatings with nano- and sub-micrometric
features. This process involves the injection of a solution spray of ceramic salts into a DC plasma jet under atmospheric
condition. During the process, the solvent vaporizes as the droplet travel downstream. Solid particles are finally formed
due to the precipitation of the solute, and the particle are heated up and accelerated to the substrate to generate the coating.
This article describes a 3D model to simulate the transport phenomena and the trajectory and heating of the solution spray
in the process. The jet-spray two-way interactions are considered. A simplified model is employed to simulate the evolution
process and the formation of the solid particle from the solution droplet in the plasma jet. The temperature and velocity
fields of the jet are obtained and validated. The particle size, velocity, temperature, and position distribution on the substrate
are predicted.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
2.
H.B. Parizi L. Rosenzweig J. Mostaghimi S. Chandra T. Coyle H. Salimi L. Pershin A. McDonald C. Moreau 《Journal of Thermal Spray Technology》2007,16(5-6):713-721
This work presents numerical simulation results for molten nickel and zirconia (YZS) droplets impacting on different microscale-patterned
surfaces of silicon. The numerical simulation clearly showed the effect of surface roughness and solidification on the shape
of the final splat, as well as the pore creation beneath the sprayed material. Simulations were performed using computational
fluid dynamic software, SimDrop. The code uses a three-dimensional finite-difference algorithm solving the full Navier-Stokes
equation, including heat transfer and phase change. A volume of fluid (VOF) tracking algorithm is used to track the droplet-free
surface. Thermal contact resistance at the droplet-substrate interface is also included in the model. Specific attention is
paid to the simulation of droplet impact under plasma spraying conditions. Droplet sizes ranged from 15 to 60 microns with
initial velocities of 70-250 m/s. Substrate surfaces were patterned with regular arrays of cubes 1-3 μm high, spaced either
1 μm or 5 μm from each other. Different splat morphologies produced by simulations are compared with those obtained from the
experiment conducted under the same impact and surface conditions.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
3.
E. Noguès P. Fauchais M. Vardelle P. Granger 《Journal of Thermal Spray Technology》2007,16(5-6):919-926
In plasma spraying, the arc-root fluctuations, modifying the length and characteristics of the plasma jet, have an important
influence on particle thermal treatment. These voltage fluctuations are strongly linked to the thickness of the cold boundary
layer (CBL), surrounding the arc column. This thickness depends on the plasma spray parameters (composition and plasma forming
gas mass flow rate, arc current, etc.) and the plasma torch design (anode-nozzle internal diameter and shape, etc.). In order
to determine the influence of these different spray parameters on the CBL properties and voltage fluctuations, experiments
were performed with two different plasma torches from Sulzer Metco. The first one is a PTF4 torch with a cylindrical anode-nozzle,
working with Ar-H2 plasma gas mixtures and the second one is a 3MB torch with either a conical or a cylindrical anode-nozzle, working with N2-H2 plasma gas mixtures. Moreover, arc voltage fluctuations influence on particle thermal treatment was studied through the measurements
of transient temperature and velocity of particles, issued from an yttria partially stabilized zirconia powder with a size
distribution between 5 and 25 μm.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
4.
J. Shimizu E. Ohmura Y. Kobayashi S. Kiyoshima H. Eda 《Journal of Thermal Spray Technology》2007,16(5-6):722-728
Three-dimensional molecular dynamics simulation was conducted to clarify at an atomic level the flattening process of a high-temperature
droplet impacting a substrate at high speed. The droplet and the substrate were assumed to consist of pure aluminum, and the
Morse potential was postulated between a pair of aluminum atoms. In this report, the influence of the impact parameters such
as the droplet velocity and the droplet diameter on flattening behavior were analyzed. As a result, the following representative
conclusions were obtained: (a) the flattening ratio increases in proportion to the droplet velocity and the droplet diameter;
(b) the flattening ratio for nanosized droplet can be reorganized by the same dimensionless parameters of the proper physical
properties, such as the viscosity and the surface tension, as those used in the macroscopic flattening process.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
5.
C. Marchand C. Chazelas G. Mariaux A. Vardelle 《Journal of Thermal Spray Technology》2007,16(5-6):705-712
Plasma spraying using liquid feedstock makes it possible to produce thin coatings (<100 μm) with more refined microstructures
than in conventional plasma spraying. However, the low density of the feedstock droplets makes them very sensitive to the
instantaneous characteristics of the fluctuating plasma jet at the location where they are injected. In this study, the interactions
between the fluctuating plasma jet and droplets are explored by using numerical simulations. The computations are based on
a three-dimensional and time-dependent model of the plasma jet that couples the dynamic behaviour of the arc inside the torch
and the plasma jet issuing from the plasma torch. The turbulence that develops in the jet flow issuing in air is modeled by
a large Eddy simulation model that computes the largest structures of the flow which carry most of the energy and momentum.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
6.
R. Etchart-Salas V. Rat J. F. Coudert P. Fauchais N. Caron K. Wittman S. Alexandre 《Journal of Thermal Spray Technology》2007,16(5-6):857-865
Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis
of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is
paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the
arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow
rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash
sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops
fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
7.
Use of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine-tune
the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro™ 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal
management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have
extended the life of the hardware. In addition the model has permitted the investigation of the fundamental operation of the
gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in
operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above
1.4 Mpa and/or voltages above 300 V that currently cannot be obtained with the physical hardware due to equipment limitations
to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro™ 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool
for applying thermal spray coatings ranging from ceramics applied at high particle temperature and low particle velocities
to carbides and alloys applied at lower temperatures and higher velocities.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
8.
J. Wilden J. P. Bergmann S. Jahn S. Knapp F. van Rodijnen G. Fischer 《Journal of Thermal Spray Technology》2007,16(5-6):759-767
Nowadays, wire-arc spraying of chromium steel has gained an important market share for corrosion and wear protection applications.
However, detailed studies are the basis for further process optimization. In order to optimize the process parameters and
to evaluate the effects of the spray parameters DoE-based experiments had been carried out with high-speed camera shoots.
In this article, the effects of spray current, voltage, and atomizing gas pressure on the particle jet properties, mean particle
velocity and mean particle temperature and plume width on X46Cr13 wire are presented using an online process monitoring device.
Moreover, the properties of the coatings concerning the morphology, composition and phase formation were subject of the investigations
using SEM, EDX, and XRD-analysis. These deep investigations allow a defined verification of the influence of process parameters
on spray plume and coating properties and are the basis for further process optimization.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
9.
The hybrid spray process that combines arc spray with a high-velocity oxyfuel (HVOF)/plasma jet has recently demonstrated
its effectiveness in deposition of functionally gradient coatings. This approach aims at exploiting the combined attributes
of the arc-spray technique and the HVOF/air plasma spraying (APS) technique. This paper presents high-speed visualization
and plume characterization of an arc/HVOF hybrid spray gun as well as a twin-wire arc-spray gun. The physics of atomization
in the hybrid spray process is examined using a high-speed camera. A DPV/CPS-2000 (Tecnar, St-Bruno, QC, Canada) particle
diagnostics sensor is used to measure particle velocity, temperature, size, and distribution. The influence of feed material,
arc parameters, and HVOF parameters on the particle characteristics is presented. Differences in the in-flight characteristics
between the hybrid and the twin-wire arc process are discussed aided by the observed atomization phenomena with the high-speed
camera.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
10.
Georg Mauer José-Luis Marqués-López Robert Vaßen Detlev Stöver 《Journal of Thermal Spray Technology》2007,16(5-6):933-939
Wear at the electrode surfaces of a one-cathode plasma torch changes the characteristic fluctuation pattern of the plasma
jet. This affects the trajectory of the particles injected into the plasma jet in a non-controllable way, which degrades the
reproducibility of the process. Time-based voltage measurements and Fourier analysis were carried out on a one-cathode F4
torch at different wear conditions to determine the evolution of wear dependant characteristics. A significant correlation
is observed between increasing torch wear and decreasing voltage roughness and high frequency noise. Furthermore, by means
of particle diagnostic systems, the change in the particle velocity and temperature has been measured. The variations of the
particle characteristics are significant and thus an influence on the sprayed coating microstructure is to be expected.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
11.
Influence of Annealing on Photocatalytic Performance and Adhesion of Vacuum Cold-Sprayed Nanostructured TiO2 Coating 总被引:1,自引:0,他引:1
Guan-Jun Yang Chang-Jiu Li Sheng-Qiang Fan Yu-Yue Wang Cheng-Xin Li 《Journal of Thermal Spray Technology》2007,16(5-6):873-880
Composite powder was prepared using primary nanoTiO2 powder and polyethylene glycol (PEG). The nanoTiO2 coating was deposited through vacuum cold spray using both the composite powder and the primary nanopowder. The influence
of annealing on the coating adhesion and photocatalytic activity was investigated. The coating adhesion was evaluated through
erosion test by water jet. The photocatalytic performance of the coatings was evaluated through photodegradation of phenol
in water. Results showed that annealing of the coating at a temperature from 450 to 500 °C yielded both higher activity and
better adhesion. The adhesion of the coating deposited using the composite powder was better than that using the primary nanoTiO2 powder. It was found that the TiO2 coating, resulting from the composite powder, presented much higher activity than that deposited with the primary nanopowder.
The better activity is attributed to the existence of large pores resulting from the stacking of composite powder, which benefits
the reactants’ transportation through the porous coating.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
12.
Carl Christoph Stahr Sabine Saaro Lutz-Michael Berger Jiri Dubský Karel Neufuss Mathias Herrmann 《Journal of Thermal Spray Technology》2007,16(5-6):822-830
A phase change from α-alumina (corundum) in the feedstock powder to predominantly other alumina phases, such as γ-alumina
in the coating normally takes place, as a result of the spray process. It is expected that the prevention of this phase transformation
will significantly improve the mechanical, electrical, and other properties of thermally sprayed alumina coatings. The results
regarding the possibility of stabilization of α-alumina through addition of chromia published in the literature are ambiguous.
In this work, stabilization using different spray processes (water-stabilized plasma (WSP), gas-stabilized plasma (APS), and
high-velocity oxy-fuel spray (HVOF)) was studied. Mechanical mixtures of alumina and chromia were used, as were prealloyed
powders consisting of solid solutions. The investigations focused on mechanical mixtures with both APS and WSP and on prealloyed
powders with WSP. The coatings were studied by x-ray diffraction, including Rietveld analysis, and analysis of the lattice
parameters. Microstructures were investigated by optical microscopy using metallographic cross-sections. It was shown that
in the case of the mechanically mixed powders, the stabilization predominantly depends on the applied spray process. The stabilization
of the α phase by use of the WSP process starting from mechanical mixtures was confirmed. It appears that stabilization exhibits
a complex dependence on the spray process, the process parameters (in particular the thermal history), the nature of the powder
(mechanically mixed or prealloyed), and the chromia content.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
13.
A. Vardelle M. Vardelle H. Zhang N. J. Themelis K. Gross 《Journal of Thermal Spray Technology》2002,11(2):244-252
Ideally, plasma spraying of metal powders must take place within a narrow processing “window” where the particles become fully
molten before they hit the substrate, but are not overheated to the point that substantial volatilization occurs. Metal evaporation
in flight results in a decrease in the deposition efficiency. In addiiton, the emission of vapors leads to the formation of
metal and oxide fumes that are undesirable from the viewpoints of both resource conservation and environmental control. This
study examines the vaporization and fume formation in the plasma spraying of iron powders of different size ranges. The experimental
part involves the determination of the population (number density) of metal atoms at different cross sections along the trajectory
of the plasma jet, and the collection of the submicronic particles resulting from vapor condensation. The experimental results
are compared with the projections of a mathematical model that computes the gas/particle velocity and temperature fields within
the jet envelope, projects the rate of heat/mass transfer at the surface of individual particles, and determines the rate
of volatilization that results in the formation of metal and metal oxide fumes.
This paper was presented at the International Thermal Spray Conference sponsored by the ASM Thermal Spray Society, the DVS-German
Welding Society and the IIW International Institute of Welding, May 8–11, 2000 in Montreal, Canada. 相似文献
14.
Dowon Seo Kazuhiro Ogawa Tetsuo Shoji Shozo Murata 《Journal of Thermal Spray Technology》2007,16(5-6):954-966
The effect of particle size distribution on the degradation behavior of plasma sprayed CoNi- and CoCrAlY coatings during isothermal
oxidation was investigated, in terms of the oxygen content, porosity, surface roughness, and oxide scale formation. The results
show that the degradation of both coatings was considerably influenced by the starting particle size distribution. It also
shows that in the as-sprayed vacuum plasma spray (VPS) coatings the oxygen content on the coating surface increased significantly
with decreased average particle size. But after thermal exposure, the difference of the oxygen contents between the coatings
with different particle size was decreased. The powder with various particle size resulted in low porosity inside the coatings
during the deposition process. The surface roughness of the coatings increased with increased particle size. The small particles
produced a relatively smooth surface, and the oxide growth in the coating deposited by small particle was slower than that
in the large particle coating.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
15.
Numerical Study of Combination Parameters for Particle Impact Velocity and Temperature in Cold Spray
Numerical simulations of gas/particle flows of cold spray are performed for N2 and He, respectively, to investigate the usefulness of the two material-independent combination parameters derived from the
equations of particle motion and temperature. The first combination parameter is the particle-diameter multiplied by the material
density, which governs the particle velocity. The second one is the squared particle-diameter multiplied by the material density
and specific heat, which affects the particle temperature. In the numerical simulation, the materials of the spray particle
selected are WC-12Co, Cu and Ti. The numerical results show that the maximum impact velocity of particle is obtained, when
the first combination parameter takes specific value regardless of the material type. Furthermore, it is shown that the particle
diameter and its temperature corresponding to the maximum impact velocity can be graphically estimated by using the two combination
parameters for any powder-materials normally used for the thermal spray.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
16.
B.R. Marple R.S. Lima C. Moreau S.E. Kruger L. Xie M. R. Dorfman 《Journal of Thermal Spray Technology》2007,16(5-6):791-797
Thermal barrier coatings were produced using both Ar and N2 as the primary plasma gas. Various aspects of the process and the coatings were investigated. It was found that higher in-flight
particle temperatures could be produced using N2, but particle velocities were lower. Deposition efficiencies could be increased by a factor of two by using N2 as compared to Ar. Coatings having similar values of porosity, hardness, Young’s modulus, and thermal diffusivity could be
produced using the two primary gases. The coatings exhibited similar changes (increased hardness, stiffness, and thermal diffusivity)
when heat-treated at 1400 °C. However, the N2-processed coatings tended to have lower values of Young’s modulus and thermal diffusivity following such treatment. The results
point to the potential advantage, in terms of reduced powder consumption and increased production rate, of using N2 as compared to Ar as the primary plasma gas for TBC deposition.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
17.
Eric Irissou Jean-Gabriel Legoux Bernard Arsenault Christian Moreau 《Journal of Thermal Spray Technology》2007,16(5-6):661-668
Coating build-up mechanisms and properties of cold-sprayed aluminum-alumina cermets were investigated using two spherical
aluminum powders having average diameters of 36 and 81 μm. Those powders were blended with alumina at several concentrations.
Coatings were produced using a commercial low-pressure cold spray system. Powders and coatings were characterized by electronic
microscopy and microhardness measurements. In-flight particle velocities were monitored for all powders. The deposition efficiency
was measured for all experimental conditions. Coating performance and properties were investigated by performing bond strength
test, abrasion test, and corrosion tests, namely, salt spray and alternated immersion in saltwater tests. These coating properties
were correlated to the alumina fraction either in the starting powder or in the coating.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
18.
Effect of Powder Injection Location on Ceramic Coatings Properties When Using Plasma Spray 总被引:1,自引:0,他引:1
The effect of powder injecting location of the plasma spraying on spraying properties was studied. Three different powder-injecting
methods were applied in the experiment. In the first method, the particles were axially injected into the plasma flow from
the cathode tip. In the second method, the particles were radially injected into the plasma flow just downstream of the anode
arc root inside the anode nozzle. In the third method, the particles were radially injected into the plasma jet at the nozzle
exit. The alumina particles with a mean diameter of 20 μm were used to deposit coatings. Spraying properties, such as the
deposition efficiency, the melting rate of the powder particles, and the coating quality were investigated. The results show
that the spraying with axial particle injecting can heat and melt the powder particles more effectively, produce coatings
with better quality, and have higher deposition efficiency.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
19.
Rodolphe Bolot Hanlin Liao Crisalia Mateus Christian Coddet Jean-Michel Bordes 《Journal of Thermal Spray Technology》2007,16(5-6):783-790
This paper presents a CFD (Computational Fluid Dynamic) study and experimental results concerning a rotating twin wire-arc
spray process for the production of coatings on engine cylinder bores. In this process, the wire atomization is performed
using a gas injection coaxially with the cylinder axis. The thermal spray tool is equipped with a deviation head rotating
around the cylinder axis and allowing deflecting the droplet spray perpendicularly to the cylinder surface. The initial deviation
head was found to be not sufficiently efficient so that a new deviation head incorporating an inclined slot was designed and
used. Both CFD results and experiments showed that this new deviation head is more efficient. Moreover, it allowed increasing
the coating bond-strength up to the specifications imposed by PSA Peugeot-Citroen. The present article shows that the wire-arc
spray technology may replace efficiently the Atmospheric Plasma Spray (APS) for the thermal spray of coatings on engine cylinder
bores. Moreover, it shows how CFD may help in solving industrial problems. In particular, the FLUENT CFD code was used in
order to perform improvements of the deviation head design.
This article was originally published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, 2007. 相似文献
20.
Solution Precursor Plasma Spray of Nickel-Yittia Stabilized Zirconia Anodes for Solid Oxide Fuel Cell Application 总被引:1,自引:0,他引:1
In conventional plasma spray of SOFC components, the large NiO and YSZ particles used, about 50-150 microns for high porosity
coating, reduce the density of three-phase sites for electrode reaction. In this article, the SPPS process was used to synthesize
and deposit Ni-YSZ anodes. The results show that several process parameters have significant effects on the microstructure
and phase composition of the deposited material. The deposits were composed of tower-like, irregularly shaped agglomerates
and smooth surface deposits. The sizes of the agglomerates increase with the decrease of the plasma-torch power and most are
not completely molten during the impact. After heat treatment to reduce the NiO present in the as deposited coatings, the
coatings were found to contain spherical YSZ particles about 0.5 μm in diameter distributed in a continuous Ni matrix, which
is verified by both SEM observation and electrical resistance measurement. The coatings have 30-50% porosity.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献