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1.
The radial injection gas dynamic spray (RIGDS) technology of powder coatings deposition was considered for this work. A coating
was created by injecting powders with variable compositions into a supersonic air jet and depositing powder on the substrate.
This study describes the preliminary analysis of an air gas dynamic spray method realized by a portable RIGDS apparatus with
a radial injection of powder. Attention was given to shock compaction processes during the coating structure formation and
examples of powder mixtures utilization in RIGDS. It was shown that the operational parameters of supersonic powder-gas jet
have a significant influence on the coating's microstructure, thus defining the high performance of the coating. Compaction
and bonding of particles were analyzed.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
2.
3.
A. A. Syed A. Denoirjean P. Denoirjean J. C. Labbe P. Fauchais 《Journal of Thermal Spray Technology》2005,14(1):117-124
Air engulfment by the plasma jet in air plasma spraying (APS) causes in-flight oxidation of metallic particles. This oxidation,
often complex and difficult to explain by classic diffusion-controlled oxidation, is governed by several mechanisms. This
paper highlights the possible in-flight oxidation mechanisms in metallic particles with a focus on the convective oxidation.
Two different types of austenitic stainless steel particles were air plasma sprayed using a direct current plasma gun and
were collected in an argon atmosphere. Preliminary experiments indicated that different mechanisms are likely to occur during
the in-flight oxidation of particles. The mass transfer from surface to interior of particle occurred, forming oxide nodules
within particles. The mass transfer is governed by convective movements inside liquid particles within the plasma jet core
due to the plasma-particle kinematic viscosity ratio greater than 50 and particle Reynolds number (Re) higher than 20. The
nodules were composed of metastable phases consisting of mixed oxide of Fe and Cr. Convective movements within particles ceased
roughly outside of the plasma jet core, and classic surface oxidation was found to be the dominant phenomenon forming the
surface oxide layer. Moreover, the molten surface oxide outside the jet core may become entrained toward the tail of the particle
if plasma conditions promote a higher particle Re number. The major oxide phase in collected particles was FeCr2O4, in a nonstoichiometric form of Fe3−x
Cr
x
O4.
The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International,
2003. 相似文献
4.
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
5.
Perovskite-type LaMnO3 powders and coatings have been prepared by a novel technique: reactive suspension plasma spraying (SPS) using an inductively
coupled plasma of approximately 40 kW plate power and an oxygen plasma sheath gas. Suitable precursor mixtures were found
on the basis of solid state reactions, solubility, and the phases obtained during the spray process. Best results were achieved
by spraying a suspension of fine MnO2 powder in a saturated ethanol solution of LaCl3 with a 1 to 1 molar ratio of lanthanum and manganese. A low reactor pressure was helpful in diminishing the amount of corrosive
chlorine compounds in the reactor. As-sprayed coatings and collected powders showed perovskite contents of 70 to 90%. After
a posttreatment with an 80% oxygen plasma, an almost pure LaMnO3 deposit was achieved in the center of the incident plasma jet.
This paper originally appeared in Thermal Spray: Meeting the Challenges of the 21st Century; Proceedings of the 15th International Thermal Spray Conference, C. Coddet, Ed., ASM International, Materials Park, OH, 1998. This proceedings paper has been extensively reviewed according
to the editorial policy of the Journal of Thermal Spray Technology. 相似文献
6.
Mathematical models for simulation of motion and heating of fine ceramic particles in plasma and laser spraying, as well as
under conditions of a new technological process, that is, hybrid laser plasma spraying, are proposed. Trajectories, velocities,
and temperature fields of fine SiO2 particles being sprayed using the argon plasma jet, CO2 laser beam, and their combination have been calculated. It is shown that the space-time distribution of temperature in spray
particles greatly depends on the spraying method.
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
7.
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
8.
Plasma sprayed cast iron coatings containing solid lubricant graphite and h-BN structure 总被引:1,自引:0,他引:1
Water-atomized cast iron powder of Fe-2.17 at.%C-9.93at.%Si-3.75at.%Al were deposited onto an aluminum alloy substrate by
atmospheric direct current plasma spraying to improve its tribological properties. Preannealing of the cast iron powder allows
the precipitation of considerable amounts of graphite structure in the powder. However, significant reduction in graphitized
carbon in cast iron coatings is inevitable after plasma spraying in air atmosphere due to the in-flight burning and dissolution
into molten iron droplets. Hexagonal boron nitride (h-BN) powders, which have excellent lubricating properties like graphite,
were incorporated into the cast iron powder as a solid lubricant by the sintering process (1300°C) to obtain protective coatings
with a low friction coefficient. The performance of each coating was evaluated using a ring-on-disk-type wear tester under
a paraffin-based oil condition in an air atmosphere. A conventional cast iron liner, which had a flaky graphite embedded in
the pearlitic matrix, was also tested under similar conditions for comparison. Sections of worn surfaces and debris were characterized,
and the wear behavior of plasma-sprayed coatings was discussed.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
9.
The thermal spraying assisted by laser (PROTAL) process combines a laser surface preparation followed by a thermal spray process.
This type of surface preparation avoids some drawbacks of the degreasing and sand blasting processes. Previous studies showed
that the adhesion of the deposits obtained with the help of the PROTAL process is similar to that achieved by traditional
surface preparation. To obtain better insight into the effects of the laser treatment, a Ni−5%Al coating was plasma sprayed
using the PROTAL process under different surface conditions. The morphology of the impinging splats and adhesion of the deposits
were examined. Removal of contaminants, adsorbates, and oxides at substrate surface is confirmed. The role of the laser irradiation
on the coating adhesion is discussed.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and IIW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
10.
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
11.
Cold spraying: Innovative layers for new applications 总被引:1,自引:0,他引:1
In recent years, results of many studies have been published that enhance understanding of the fundamental mechanisms of cold-spray
coating generation and bonding as well as coating characteristics. From the points of view of a job shop in thermal spraying
and of a user of cold-spraying equipment, a procedure, being used in development of new applications is presented herein.
In addition to the technical requirements, some general factors determining the success of industrial use of spraying are
shown. Examples of coldsprayed coatings are described to shos both the possibility of rapid integration of this new technique
in established coating jobs as wells as exploration and use of new possibilities in cold spraying and development of applications
that have not yet been a focus of thermal spray techniques. Suggestions for further research and development activities are
made on the basis of practical cold-spray experience.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, Internaltional Thermal Spray Conference, sponsored by DVS, ASM International, and IIW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
12.
L. C. Erickson T. Troczynski H. M. Hawthorne H. Tai D. Ross 《Journal of Thermal Spray Technology》1999,8(3):421-426
A series of plasma sprayed coatings of controlled microstructure was obtained by spraying three monosize sapphire powders
using an axial injection torch in which the plasma gas composition and nozzle diameter were the only processing parameters
varied. The effects of changes in these parameters on the coating splat morphology, porosity, angular crack distribution,
and hardness are reported. The uniform, dense microstructure and the high hardness of 14 GPa (a level usually only associated
with chromia thermal spray coatings) of the best alumina coatings resulted from using tightly controlled processing conditions
and monodispersed precursor powders. The microstructural quality of plasma sprayed coatings and, hence, the coating properties
can be improved significantly by minimizing variations in processing and raw material parameters.
This paper originally appeared in Thermal Spray: Meeting the Challenges of the 21st Century; Proceedings of the 15th International Thermal Spray Conference, C. Coddet, Ed., ASM International, Materials Park, OH, 1998. This proceedings paper has been extensively reviewed according
to the editorial policy of the Journal of Thermal Spray Technology. 相似文献
13.
Finely structured ceramic coatings can be obtained by solution precursor plasma spraying. The final structure of the coating
highly depends on the droplet size and velocity distribution at the injection, the evolution of the spray in the jet, and
droplet breakup and collision within the spray. This article describes a 3D model to simulate the transport phenomena and
the trajectory and heating of the solution spray in the process. O’Rourke’s droplet collision model is used to take into account
the influence of droplet collision. The influence of droplet breakup is also considered by implementing TAB droplet breakup
models into the plasma jet model. The effects of droplet collisions and breakup on the droplet size, velocity, and temperature
distribution of the solution spray are investigated. The results indicate that droplet breakup and collision play an important
role in determining the final particle size and velocity distributions on the substrate.
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
14.
B. G. Ravi S. Sampath R. Gambino J. B. Parise P. S. Devi 《Journal of Thermal Spray Technology》2006,15(4):701-707
Precursor plasma spray synthesis is an innovative and rapid method for making functional oxide ceramic coatings by starting
from solution precursors and directly producing inorganic films. This emerging method utilizes molecularly mixed precursor
liquids, which essentially avoids the handling and selection of powders, opening up new avenues for developing compositionally
complex functional oxide coatings. Precursor plasma spray also offers excellent opportunities for exploring the nonequilibrium
phase evolution during plasma spraying of multicomponent oxides from inorganic precursors. Although there have been efforts
in this area since the 1980s and early 1990s with the goal of synthesizing nanoparticles, only recently has the work progressed
in the area of functional systems. At the Center for Thermal Spray Research an integrated investigative strategy has been
used to explore the benefits and limits of this synthesis strategy. Water- and alcohol-based sol/solution precursors derived
from various chemical synthesis methods were used as feedstocks to deposit thin/thick films of spherical and nanostructured
coatings of yttrium aluminum garnet (YAG), yttrium iron garnet, lanthanum strontium manganate and Zr-substituted yttrium titanates,
and compositions of Y2O3-Al2O3 and their microstructural space centered around stoichiometric YAG. A detailed discussion of the salient features of the
radiofrequency induction plasma spraying approach, the results obtained in the investigations to develop various functional
oxide coatings, and process issues and challenges are presented.
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
15.
Nanostructured WC-12% Co coatings were deposited by suspension plasma spraying of submicron feedstock powders, using an internal
injection plasma torch. The liquid carrier used in this approach allows for controlled injection of much finer particles than
in conventional thermal spraying, leading to thin coatings with a fine surface finish. A polyethylene-imine (PEI) dispersant
was used to stabilize the colloidal suspension in an ethanol carrier. In-flight particle states were measured for a number
of operating conditions of varying plasma gas flow rates, feed rates, and standoff distances and were related to the resulting
microstructure, phase composition (EDS, SEM, XRD), and Vickers hardness. High in-flight particle velocities (>800 m/s) were
generated, leading to dense coatings. It was observed that the coating quality was generally compromised by the high temperature
and reactivity of the small particles. To compensate for this shortcoming, the suspension feed rate was adjusted, thereby
varying the thermal load on the plasma. Results showed that a slightly larger agglomerate size, in conjunction with low particle
jet temperatures, could somewhat limit the decomposition of WC into brittle W2C/W3C and amorphous cobalt containing binder phases.
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
16.
Andreas Wank Bernhard Wielage Harry Podlesak Thomas Grund 《Journal of Thermal Spray Technology》2006,15(2):280-283
Interfaces between light metal alloys, aluminum AA7022, and magnesium AZ91, and optimized cold gassprayed zinc-based coatings
are characterized. The analyses include scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM).
Investigations by SEM show a seam with intensive mixing of the substrate and coating material, which is indicated by different
values of gray due to element contrast. In energy-dispersive spectroscopy analyses, increased zinc concentrations compared
with the substrate material are detected in <1 μm thick vortexes inside the seam. The TEM investigations prove that these
areas consist of a homogeneous solid solution and submicron-sized or nanosized intermetallic phases with different concentrations
of aluminum, zinc, and magnesium. Because diffusion processes cannot result in the observed microstructure. local melting
followed by precipitation of intermetallic phases is concluded as the consequence of the intensive mechanical interaction
at the substrate-coating interface during particle impact during the cold gas spraying of zinc on magnesium or aluminum substrates.
The original version of this paper was published in the CD ROM Thermal Spray Commects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
17.
Copper (Cu) coating was deposited by cold spraying, and the electrical resistivity of the coating in both directions parallel
and perpendicular to the coating surface was measured to investigate the anisotropy of the coating. Annealing treatment was
applied to the coating to examine its effect on the microstructure and properties of the cold-sprayed Cu coating. The examination
of coating microstructure evidently revealed that the coating was constituted by the flattened particles, and the interfaces
were clearly observed between the deposited particles. The anisotropy in microstructure and electrical resistivity was present
in cold-sprayed Cu coating. The electrical resistivity of the as-sprayed coating was higher than that of Cu bulk. Moreover,
the electrical resistivity along the direction parallel to the coating surface was lower than that along the perpendicular
direction. It was found that annealing treatment led to the enhancement of particle interface bonding and evident recry stallization
of the elongated grains and remarkable grain growth as well. The annealed coating presented equiaxed grain structures similar
to the annealed Cu bulk with particle interfaces almost disappearing under certain annealing conditions. The coalescence of
voids or pores in the coating was clearly observed at high annealing temperatures. Moreover, the annealed coating yielded
an electrical resistivity and microhardness comparable to Cu bulk.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
18.
L. Ajdelsztajn A. Zúñiga B. Jodoin E. J. Lavernia 《Journal of Thermal Spray Technology》2006,15(2):184-190
This work describes recent progress in cold-spray processing of conventional and nanocrystalline 2618 (Al−Cu−Mg−Fe−Ni) aluminum
alloy containing scandium (Sc). As-atomized and cryomilled 2618+Sc aluminum powder were sprayed onto aluminum substrates.
The mechanical behavior of the powders and the coatings were studied using micro-and nanoindentation techniques, and the microstructure
was analyzed using scanning and transmission electron microscopy (SEM and TEM). The influence of powder microstructure, morphology,
and behavior during deposition on the coating properties was analyzed. This work shows that Al−Cu−Mg−Fe−Ni−Sc coatings with
a nanocrystalline grain structure can be successfully produced by the cold-spray process. Inspection of the scientific literature
suggests that this is the first time a hardness value of 181 HV has been reported for this specific alloy.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and IIW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
19.
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
20.
Hybrid plasma spraying combined with yttrium-aluminum-garnet laser irradiation was studied to obtain optimum zirconia coatings
for thermal barrier use. Zirconia coatings of approximately 150 μm thickness were formed on NiCrAlY bond coated steel substrates
both by means of conventional plasma spraying and hybrid plasma spraying under a variety of conditions. Post-laser irradiation
was also conducted on the plasma as-sprayed coating. The microstructure of each coating was studied and, for some representative
coatings, thermal barrier properties were evaluated by hot erosion and hot oxidation tests. With hybrid spraying, performed
under optimum conditions, it was found that a microstructure with appropriate partial densification and without connected
porosity was formed and that cracks, which are generally produced in the post-laser irradiation treatment, were completely
inhibited. In addition, hybrid spraying formed a smooth coating surface. These microstructural changes resulted in improved
coating properties with regard to hardness, high temperature erosion resistance, and oxidation resistance.
This paper originally appeared in Thermal Spray: Meeting the Challenges of the 21st Century; Proceedings of the 15th International Thermal Spray Conference, C. Coddet, Ed., ASM International, Materials Park, OH, 1998. This proceedings paper has been extensively reviewed according
to the editorial policy of the Journal of Thermal Spray Technology. 相似文献