Thermal Spray Forming Using the HVOF Technique

1997 ◽  
Author(s):  
J.M. Guilemany ◽  
J.R. Miguel ◽  
M.J. Dougan ◽  
J.M. de Paco ◽  
Z. Dong ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Spray Forming ◽  
Homogeneous Distribution ◽  
Material Decomposition ◽  
Hvof Spraying ◽  
Free Standing ◽  
Hvof Spray ◽  
The Matrix ◽  
Low Levels ◽  
Microstructural Examination

Abstract The feasibility of using the HVOF process for the thermal spray-forming of free-standing components has been investigated. HVOF spray forming offers a number of potential advantages compared to the established procedure of plasma forming, including increases in component density, and reduction in material decomposition during spraying. Using blends of carbide and superalloy powders in various proportions, HVOF spraying has been successfully used to form free-standing cylinders and cones of various lengths and thicknesses. Microstructural examination of the spray-formed material has shown a homogeneous distribution of carbides in the superalloy matrix, with very low levels of porosity. Refinement of the procedure has allowed reduction of the matrix content, and the forming of fragile materials.

Obtention and Development of Blends of Powder to Obtain Free-Standing Components Produced by HVOF Spray-Forming

1998 ◽  
Author(s):  
J.M. Guilemany ◽  
J.M. De Paco ◽  
J.R. Miguel ◽  
J. Llibre
Keyword(s):  
Spray Forming ◽  
Homogeneous Distribution ◽  
Material Decomposition ◽  
Hvof Spraying ◽  
Free Standing ◽  
Hvof Process ◽  
Hvof Spray ◽  
Low Levels ◽  
Disk Test ◽  
Microstructural Examination

Abstract The feasibility of using the HVOF process for the thermal spray-forming of free-standing components has been investigated. HVOF spray forming offers a number of potential advantages compared to the established procedure of plasma forming, including increases in component density, and reduction in material decomposition during spraying. Using blends of carbide and superalloy powders in various proportions, HVOF spraying has been successfully used to form free-standing cylinders and cones of various lengths and thicknesses. Microstructural examination of the spray-formed material, using optical microscopy and scanning electron microscopy (SEM), has shown a homogeneous distribution of carbides in the superalloy matrix, with very low levels of porosity. Vickers microhardness has been measured on several sprayed forms. In order to complete the study of the different systems, abrasion (Rubber Wheel Test), friction (Ball on Disk Test) and erosion wear results have been obtained. These wear results have been used in order to evaluate the behaviour of the sprayed samples with a different powder percentage in the blends. Corrosion tests have been done to evaluate the corrosion resistance of the sprayed samples (ASTM D-1411).

Carbon Nanotube Reinforced Aluminum Nanocomposite via Plasma and High Velocity Oxy-Fuel Spray Forming

2007 ◽  
Vol 7 (2) ◽  
pp. 515-524 ◽  
Author(s):  
T. Laha ◽  
Y. Liu ◽  
A. Agarwal
Keyword(s):  
Carbon Nanotubes ◽  
High Velocity ◽  
Thermal Spraying ◽  
Spray Forming ◽  
Al Alloy ◽  
Free Standing ◽  
Multiwalled Carbon ◽  
Alloy Matrix ◽  
Property Evaluation ◽  
Hvof Spray

Free standing structures of hypereutectic aluminum-23 wt% silicon nanocomposite with multiwalled carbon nanotubes (MWCNT) reinforcement have been successfully fabricated by two different thermal spraying technique viz Plasma Spray Forming (PSF) and High Velocity Oxy-Fuel (HVOF) Spray Forming. Comparative microstructural and mechanical property evaluation of the two thermally spray formed nanocomposites has been carried out. Presence of nanosized grains in the Al–Si alloy matrix and physically intact and undamaged carbon nanotubes were observed in both the nanocomposites. Excellent interfacial bonding between Al alloy matrix and MWCNT was observed. The elastic modulus and hardness of HVOF sprayed nanocomposite is found to be higher than PSF sprayed composites.

Carbon Nanotube Reinforced Aluminum Nanocomposite via Plasma and High Velocity Oxy-Fuel Spray Forming

2007 ◽  
Vol 7 (2) ◽  
pp. 515-524 ◽  
Author(s):  
T. Laha ◽  
Y. Liu ◽  
A. Agarwal
Keyword(s):  
Carbon Nanotubes ◽  
High Velocity ◽  
Thermal Spraying ◽  
Spray Forming ◽  
Al Alloy ◽  
Free Standing ◽  
Multiwalled Carbon ◽  
Alloy Matrix ◽  
Property Evaluation ◽  
Hvof Spray

Free standing structures of hypereutectic aluminum-23 wt% silicon nanocomposite with multiwalled carbon nanotubes (MWCNT) reinforcement have been successfully fabricated by two different thermal spraying technique viz Plasma Spray Forming (PSF) and High Velocity Oxy-Fuel (HVOF) Spray Forming. Comparative microstructural and mechanical property evaluation of the two thermally spray formed nanocomposites has been carried out. Presence of nanosized grains in the Al–Si alloy matrix and physically intact and undamaged carbon nanotubes were observed in both the nanocomposites. Excellent interfacial bonding between Al alloy matrix and MWCNT was observed. The elastic modulus and hardness of HVOF sprayed nanocomposite is found to be higher than PSF sprayed composites.

scholarly journals Thermal degradation of hemicellulose and cellulose in ball-milled cedar and beech wood

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jiawei Wang ◽  
Eiji Minami ◽  
Mohd Asmadi ◽  
Haruo Kawamoto
Keyword(s):  
Thermal Degradation ◽  
Ball Milling ◽  
Cell Walls ◽  
Uronic Acid ◽  
Beech Wood ◽  
Cellulose Microfibrils ◽  
Homogeneous Distribution ◽  
Japanese Beech ◽  
Temperature Range ◽  
The Matrix

AbstractThe thermal degradation reactivities of hemicellulose and cellulose in wood cell walls are significantly different from the thermal degradation behavior of the respective isolated components. Furthermore, the degradation of Japanese cedar (Cryptomeria japonica, a softwood) is distinct from that of Japanese beech (Fagus crenata, a hardwood). Lignin and uronic acid are believed to play crucial roles in governing this behavior. In this study, the effects of ball milling for various durations of time on the degradation reactivities of cedar and beech woods were evaluated based on the recovery rates of hydrolyzable sugars from pyrolyzed wood samples. The applied ball-milling treatment cleaved the lignin β-ether bonds and reduced the crystallinity of cellulose, as determined by X-ray diffraction. Both xylan and glucomannan degraded in a similar temperature range, although the isolated components exhibited different reactivities because of the catalytic effect of uronic acid bound to the xylose chains. These observations can be explained by the more homogeneous distribution of uronic acid in the matrix of cell walls as a result of ball milling. As observed for holocelluloses, cellulose in the ball-milled woods degraded in two temperature ranges (below 320 °C and above); a significant amount of cellulose degraded in the lower temperature range, which significantly changed the shapes of the thermogravimetric curves. This report compares the results obtained for cedar and beech woods, and discusses them in terms of the thermal degradation of the matrix and cellulose microfibrils in wood cell walls and role of lignin. Such information is crucial for understanding the pyrolysis and heat treatment of wood.

Graphite/UPE Nanocomposite: Transport, Thermal, Mechanical and Viscoelastic Properties

2019 ◽  
Vol 23 ◽  
pp. 201-212
Author(s):  
Shivkumari Panda ◽  
Dibakar Behera ◽  
Tapan Kumar Bastia
Keyword(s):  
Transport Properties ◽  
Unsaturated Polyester ◽  
Homogeneous Distribution ◽  
Thermo Gravimetric ◽  
New Class ◽  
The Matrix ◽  
Novel Method ◽  
Water Transport Properties ◽  
First Time

This chapter presents the preparation and characterization of some unique properties of nanocomposites by dispersing graphite flakes in commercial unsaturated polyester (UPE) matrix. The composite was prepared by a novel method with the use of solvent swelling technique. Three different specimens of UPE/graphite nanocomposites were fabricated with addition of 1, 2 and 3 wt% of graphite flakes. Except mechanical, viscoelastic and thermo gravimetric properties, transport properties like electrical conductivity, thermal conductivity and water transport properties were studied for the first time. Graphite flakes propose enhanced properties to the composites suggesting homogeneous distribution of the nanofiller in the matrix and strong interaction with the matrix. 2wt% nanofiller loading showed superior essential characteristics and after that the properties reduced may be due to the nucleating tendency of the nanofiller particles. The XRD pattern showed the compatibility of the graphite flakes by introducing a peak around 26.550 in the nanocomposites. SEM Properties are also in agreement with the compatibility. Nanocomposite with 2wt% graphite also showed remarkable enhancement in transport, mechanical, viscoelastic and thermo gravimetric properties. So by introduction of a small quantity of graphite endow the new class of multiphase nanocomposites with inimitable structure and tremendous application.

Plasma-Spray-Forming of Alumina Matrix Composite Reinforced with Metal Thin Wire

2000 ◽  
Author(s):  
S. Sodeoka ◽  
T. Inoue ◽  
M. Suzuki
Keyword(s):  
Plasma Spray ◽  
Spray Forming ◽  
Filament Winding ◽  
Atmospheric Plasma ◽  
Thin Wire ◽  
Alumina Matrix ◽  
Plasma Spray Forming ◽  
Inconel 600 ◽  
The Matrix ◽  
The Wire

Abstract Alumina matrix composites reinforced with metal thin wire (Inconel-600) were successfully fabricated by plasma spray forming. The atmospheric plasma sprayed matrix layers and wire layers arranged by filament-winding technique were piled up alternately. Though the matrix and the wire were partially bonded only on the side which sprayed particles came flying to, a solid structure was obtained by this technique. Spraying in one direction perpendicular to the substrate made peculiar V-shape pores around the wires, but tilting the torch was effective to reduce the pores. The flexural strength of composite did not increase in spite of some crack deflections on the fracture surface. Owing to the wire pullout, however, the composite exhibited a remarkably higher apparent fracture energy than that of monolithic alumina ceramics.

Sprayability and Properties of TiC-Ni Based Powders in the Detonation Gun and HVOF Processes

1997 ◽  
Author(s):  
P. Vuoristo ◽  
T. Mäntylä ◽  
L.-M. Berger ◽  
M. Nebelung
Keyword(s):  
Wear Test ◽  
Binder Content ◽  
Binder Phase ◽  
Coating Properties ◽  
X Ray Diffraction ◽  
Hvof Spraying ◽  
Hvof Process ◽  
Hvof Spray ◽  
Structures And Properties ◽  
Detonation Gun

Abstract Agglomerated and sintered TiC-Ni based powders were sprayed by detonation gun spray (DGS) and high-velocity oxy-fuel (HVOF) spray processes. Influence of the binder content (20 and 27 vol.-%) and some alloying elements, such as Mo, Co and N on the coating properties were investigated. The coating structures and properties were investigated by optical microscopy, hardness measurements, X-ray diffraction analysis and by rubber-wheel abrasion wear test. It was found that alloying the hard phase with Mo and N leads to an improvement of the coating properties. Alloying of the binder phase with Co did not affect the coating properties. Porosity in the powder granules was found to beneficial in order to melt more efficiently the particles in the DGS process and especially in the HVOF process. HVOF spraying of powders with the higher binder content of 27 vol.-% was found to be advantageous for the preparation of coatings with dense microstructures and good wear resistances.

Particle Temperature Measurements by Spectroscopic and Two-Wavelength Streak Imaging

2000 ◽  
Author(s):  
J.E. Craig ◽  
R.A. Parker ◽  
F.S. Biancaniello ◽  
S.D. Ridder ◽  
S.P. Mates
Keyword(s):  
Thermal Spray ◽  
High Performance ◽  
Particle Temperature ◽  
Ceramic Powder ◽  
Spray Forming ◽  
Temperature Measurements ◽  
Sensor Technology ◽  
Depth Of Field ◽  
Velocity Change ◽  
Processing Technologies

Abstract A two-wavelength particle imaging pyrometer has been developed to measure temperature, velocity and size of individual particles within a field of view and a depth of field that spans the entire particle stream in most thermal spray devices. The pyrometer provides continuous updates to particle condition profiles, histograms and correlations. The software locates particle streaks, determines the intensity ratio and dimensions of each streak, and calculates the particle temperature, velocity and size. Many forms of advanced materials processing technologies, such as thermal spray, spray-forming and atomization processes, have considerable need of process control sensor technology. These measurements provide the basis for application of the pyrometer to many of these processes. Particle temperature measurements of plasma-sprayed ceramic powder were obtained using a spectrometer and the pyrometer. Comparisons of the measurements show that the vision-based pyrometer has excellent accuracy. The standard deviation of the measurements was 40 K or about 1.3 %. Additional pyrometer measurements were used to determine its minimum detectable temperature and velocity change, which were 12.4 K and 2.77 m/s, or 0.4 % and 1.5 %, respectively. The vision-based particle sensor can now be applied to high performance control strategies to provide stable particle temperatures and velocities over long duration plasma spray processes.

scholarly journals The Effect of Reinforcement Ratio on the Composite Structure and Mechanical Properties in Al-MgO Composites Produced by the Melt Stirring Method

2011 ◽  
Vol 20 (4) ◽  
pp. 096369351102000 ◽  
Author(s):  
Recep Çalin ◽  
Pul Muharrem ◽  
Ramazan Çitak ◽  
Ulvi Şeker
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Metal Matrix ◽  
Vertical Direction ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
Liquid Matrix ◽  
The Matrix ◽  
Micro Structures ◽  
Scanning Electron

In this study, Al- MgO metal matrix composites (MMC) were produced with 5 %, 10 % and 15 % reinforcement- volume (R-V) ratios by the melt stirring method. In the production of composites 99.5 % pure Al was used as the matrix and MgO powders with the particle size of −105 μm were used as the reinforcement. For every R-V ratio; stirring was made at 500 rev/min at 750°C liquid matrix temperature for 4 minutes and the samples were cooled under normal atmosphere. Then hardness and fracture strengths of the samples were determined and their micro structures were evaluated by using Scanning Electron Microscope (SEM). In general, it was observed that the reinforcement exhibited a homogeneous distribution in horizontal direction. But there is a slight inhomogeneity in vertical direction. It was determined that the increase in the R-V ratio increased the porosity and also the hardness. As for the fracture strength, the highest strength was obtained with the 5 % MgO reinforced sample.

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