Evaluation of Four High Velocity Thermal Spray Guns Using WC-10Co-4Cr Cermets

2000 ◽  
Author(s):  
J.G. Legoux ◽  
B. Arsenault ◽  
C. Moreau ◽  
V. Bouyer ◽  
L. Leblanc
Keyword(s):  
Tungsten Carbide ◽  
Thermal Spray ◽  
Particle Velocity ◽  
High Velocity ◽  
Vickers Microhardness ◽  
Particle Temperature ◽  
Deposition Efficiency ◽  
Plasma Gun ◽  
Flight Velocity ◽  
Standard Version

Abstract Four high velocity thermal spray guns were evaluated in the production of 10%Co-4%Cr tungsten carbide cermets. Three HVOF guns (the JP-5000, JP-5000ST and DJ-2700) and one plasma gun, (the Mettech Axial III) were used to spray the same angular, agglomerated and crushed WC-10Co-4Cr powder. The DPV-2000 was used to monitor the in-flight velocity and temperature of the WC cermet sprayed particles. From those values, spray conditions were selected to produce coatings that were evaluated in terms of porosity, hardness and deposition efficiency. Results show that the plasma Axial III provides the highest particle temperature, between 2000°C and 2600°C, depending on the spray conditions. The JP-5000 imparts the highest velocity to the particles, between 550 m/s and 700 m/s, depending on the spray conditions. The ST version of the JP-5000 provides the same velocity as the standard version but with lower particle temperature. The DJ-2700 sprays particles with temperature and velocity between those of the JP5000 and the Mettech Axial III. Minimum porosity values of 2.1%, 3.7% and 5.3%) were obtained for the JP-5000, the DJ-2700 and the Axial III guns respectively. The porosity and carbide degradation are found to mostly depend on the particle velocity and temperature respectively. The values for the Vickers microhardness number (200g) ranged from 950 to 1250. Measurements of the deposition efficiency indicated a variation between 10 and 80%o, depending on the spray conditions and the gun used.

Particle Velocity and Temperature influences on the Microstructure of Plasma Sprayed Nickel

1996 ◽  
Author(s):  
R.N. Wright ◽  
J.R. Fincke ◽  
W.D. Swank ◽  
D.C. Haggard
Keyword(s):  
Relative Density ◽  
Particle Velocity ◽  
Particle Temperature ◽  
Deposition Efficiency ◽  
Nickel Coatings ◽  
Higher Temperature ◽  
Velocity Changes ◽  
Particle Velocities ◽  
Lower Temperature ◽  
Plasma Sprayed

Abstract The variation in microstructure of high power plasma sprayed nickel coatings deposited with particle velocities ranging from 150 to 425 m/s and nominal particle temperatures of 1650 or 2050°C has been characterized. The relative density of coatings produced at the higher temperature is above 99.5% of theoretical regardless of the particle velocity; at the lower particle temperature the relative density is found to increase with increasing particle velocity. The fraction of unmelted particles is also found to increase with increasing velocity at the lower temperature. The relative deposition efficiency is approximately twice as high for the lower temperature particles compared to the high temperature, and for both temperatures the deposition efficiency decreases substantially with increasing velocity. Changes in the morphology of individual splats with changes in particle characteristics are also described.

scholarly journals Computational Fluid Dynamics Analysis of a Wire-Feed, High-Velocity Oxygen-Fuel (HVOF) Thermal Spray Torch

1996 ◽  
Author(s):  
A.R. Lopez ◽  
B. Hassan ◽  
W.L. Oberkampf ◽  
R.A. Neiser ◽  
T.J. Roemer
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Thermal Spray ◽  
Particle Velocity ◽  
High Velocity ◽  
Combustion Process ◽  
High Velocity Oxygen Fuel ◽  
Computational Fluid Dynamics Analysis ◽  
Oxygen Fuel ◽  
Wire Feed

Abstract The fluid and particle dynamics of a High-Velocity Oxygen-Fuel Thermal Spray torch are analyzed using computational and experimental techniques. Three-dimensional Computational Fluid Dynamics (CFD) results are presented for a curved aircap used for coating interior surfaces such as engine cylinder bores. The device analyzed is similar to the Metco Diamond Jet Rotating Wire (DJRW) torch. The feed gases are injected through an axisymmetric nozzle into the curved aircap. Premixed propylene and oxygen are introduced from an annulus in the nozzle, while cooling air is injected between the nozzle and the interior wall of the aircap. The combustion process is modeled using a single-step finite- rate chemistry model with a total of 9 gas species which includes dissociation of combustion products. A continually-fed steel wire passes through the center of the nozzle and melting occurs at a conical tip near the exit of the aircap. Wire melting is simulated computationally by injecting liquid steel particles into the flow field near the tip of the wire. Experimental particle velocity measurements during wire feed were also taken using a Laser Two-Focus (L2F) velocimeter system. Flow fields inside and outside the aircap are presented and particle velocity predictions are compared with experimental measurements outside of the aircap.

Plasma Technology TRIPLEX for the Deposition of Ceramic Coatings in the Industry

2000 ◽  
Author(s):  
G. Barbezat ◽  
K. Landes
Keyword(s):  
Plasma Jet ◽  
Life Time ◽  
Deposition Efficiency ◽  
Ceramic Coatings ◽  
Injection System ◽  
Oxide Ceramic ◽  
Long Distance ◽  
Plasma Gun ◽  
Plasma Torches ◽  
Improved Stability

Abstract As a new plasma gun technology the TRIPLEX system has been introduced in the industrial field two years ago. The core of the TRIPLEX technology is a plasma gun with three cathodes and a long cascaded nozzle consisting of several insulated rings. Only the last ring with a relatively long distance to the cathode is operated as anode. Because of the equal and constant lengths of the three independent arcs, stretching from the three cathodes to the common anode, a stationary plasma jet is generated. Compared to conventional torches, the improved stability of the plasma jet allows a more uniform powder treatment and a higher deposition efficiency as well as the powder feed rate can be increased using a triple injection system. A significantly longer life time of the electrodes reduces the cost for quality control in the coating process. The characteristic properties of oxide ceramic coatings are improved in comparison with the coatings produced by conventional plasma torches. The results of two years industrial application of the innovative torch system TRIPLEX are presented in the paper.

scholarly journals Pengaruh Proses Oksidasi Lapisan Metal Matrix Composite pada Substrat SS316

2019 ◽  
Vol 4 (2) ◽  
pp. 277
Author(s):  
Erie Martides ◽  
Candra Dewi Romadhona ◽  
Djoko Hadi Prajitno ◽  
Budi Prawara
Keyword(s):  
Metal Matrix Composite ◽  
Thermal Spray ◽  
Matrix Composite ◽  
High Velocity ◽  
Metal Matrix ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
High Velocity Oxygen Fuel ◽  
Hvof Thermal Spray ◽  
Oxygen Fuel

Material SS316 seringkali digunakan untuk komponen yang bekerja pada temperatur tinggi dengan resiko mengalami oksidasi yang menyebabkan penurunan sifat material dan umur pakai dari komponen. Deposisi Metal Matrix Composite (MMC) NiCr+Cr3C2+Al2O3 dan NiCr+WC12Co+Al2O3 menggunakan metode High Velocity Oxygen Fuel (HVOF) thermal spray coating dengan parameter konstan dilakukan sebagai proses perlakuan pada permukaan SS316 untuk meningkatkan nilai kekerasan dan ketahanan terhadap oksidasi.  Tujuan penelitian ini adalah untuk mengetahui pengaruh proses oksidasi lapisan MMC pada material substrat SS316. Proses oksidasi dilakukan dengan variasi temperatur 500° dan 600°C, penahanan temperatur selama 6 jam, kemudian diteruskan dengan karakterisasi serta perhitungan laju oksidasi. Hasil penelitian menunjukkan spesimen MMC NiCr+Cr3C2+Al2O3 yang dilakukan proses oksidasi pada suhu 500°C memiliki laju oksidasi terendah yaitu 6,67 x 10-7 gram/mm2 jam. 

A Splats Obtaining System for Thermal Spray Deposits

2007 ◽  
Vol 561-565 ◽  
pp. 1169-1172 ◽  
Author(s):  
W.T. Hsiao ◽  
W.H. Liao ◽  
M.S. Leu ◽  
Cherng Yuh Su
Keyword(s):  
Thermal Spray ◽  
High Velocity ◽  
Glass Substrate ◽  
Single Spot ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Hvof Process

The image of thermal spray splats is difficult to collect due to its high velocity of droplets. Especial in High Velocity Oxy-Fuel (HVOF) process, the process present higher velocity of flame jet correlated to other thermal spray process. The system presents at this article describes a useful splats catching method to obtaining splats during thermal spray deposited. Capabilities and advantages of using this instrument are declared at this theme. The final result presented the instrument caught the single spot of HVOF sprayed splats at sub-micro second. Splats of spot were dispersed well on the glass substrate at the obtaining system, and presented various information of droplets impact at different location on the substrate.

High Velocity Pulsed Plasma Thermal Spray

2000 ◽  
Author(s):  
F.D. Witherspoon ◽  
D.W. Massey ◽  
R.W. Kincaid ◽  
G.C. Whichard ◽  
T.A. Mozhi
Keyword(s):  
Thermal Spray ◽  
High Velocity ◽  
Vacuum Chamber ◽  
Thermal Environment ◽  
Diagnostic System ◽  
Inert Atmosphere ◽  
Pulsed Plasma ◽  
Combustible Gases ◽  
Accelerated Particles

Abstract The quality and durability of coatings produced by virtually all thermal spray techniques could be improved by increasing the velocity with which coating particles impact the substrate. Additionally, better control of the chemical and thermal environment seen by the particles during flight is crucial to the quality of the coating. A high velocity thermal spray device is under development through a BMDO SBIR project which provides significantly higher impact velocity for accelerated particles than is currently available with existing thermal spray devices. This device utilizes a pulsed plasma as the accelerative medium for powders introduced into the barrel. Recent experiments using a Control-Vision diagnostic system showed that the device can accelerate stainless steel and WC-Co powders to velocities ranging from 1500 to 2200 m/s. These high velocities are accomplished without the use of combustible gases, and without the need of a vacuum chamber, while maintaining an inert atmosphere for the particles during acceleration. The high velocities corresponded well to modeling predictions, and these same models suggest that velocities as high as 3000 m/s or higher are possible.

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