Plasma Spraying of Zirconia Coatings

1989 ◽  
Vol 155 ◽  
Author(s):  
D. J. Varacalle ◽  
G. R. Smolik ◽  
G. C. Wilson ◽  
G. Irons ◽  
J. A. Walter
Keyword(s):  
Gas Flow ◽  
Analytical Study ◽  
Numerical Models ◽  
Fractional Factorial ◽  
Spray Parameters ◽  
X Ray Diffraction ◽  
Physical Processes ◽  
Particle Injection ◽  
Carrier Gas Flow ◽  
Temperature And Flow Fields

ABSTRACTAs part of an investigation of the dynamics that occur in the plume of a thermal spray torch, an experimental and analytical study of the deposition of yttria-stabilized zirconia has been accomplished. Experiments were conducted using a Taguchi fractional factorial design. Nominal spray parameters were: 900 A, 36 kW, 100 scfh argon primary gas flow, 47 scfh helium secondary gas flow, 11.5 scfh argon powder carrier gas flow, 3.5 lb/h powder feed rate, 3 in. spray distance, and an automated traverse rate of 20 in./s. The coatings were characterized for thickness, hardness, and microstructural features with optical microscopy, scanning electron microscopy, and x-ray diffraction. Attempts are made to correlate the features of the coatings with the changes in operating parameters. Numerical models of the physical processes in the torch column and plume were used to determine the temperature and flow fields. Computer simulations of particle injection (10 to 75 μm zirconia particles) are presented.

An Analytical and Experimental Study of Plasma Spraying of Alumina

1988 ◽  
Vol 121 ◽  
Author(s):  
D. J. Varacalle
Keyword(s):  
Experimental Study ◽  
Plasma Spraying ◽  
Numerical Models ◽  
Power Level ◽  
Hydrogen Gas ◽  
Physical Processes ◽  
Particle Injection ◽  
Alumina Particles ◽  
Temperature And Flow Fields

ABSTRACTAs part of an investigation of the dynamics that occur in the plume of a typical thermal spray torch, an analytical and experimental study of the plasma spraying of alumina is being performed; preliminary results are reported here. Numerical models of the physical processes in the torch column and plume were used to determine the temperature and flow fields. Computer simulations of particle injection (15, 34, and 53 μm alumina particles) are also presented. The alumina experiments were conducted at a 35 kW power level using a 100 scfh argon and 15 scfh hydrogen gas mixture for two alumina powders. The quality of the coatings is discussed with respect to porosity, sample metallography, and microhardness.

Process Maps for Plasma Spray Part I: Plasma-Particle Interactions

2000 ◽  
Author(s):  
D.L. Gilmore ◽  
R.A. Neiser ◽  
Y. Wan ◽  
S. Sampath
Keyword(s):  
Plasma Spray ◽  
Gas Flow ◽  
Operating Conditions ◽  
Injection Velocity ◽  
Microstructural Development ◽  
Spray Parameters ◽  
Particle Interactions ◽  
Plasma Particle ◽  
Particle Injection ◽  
Process Maps

Abstract This is the first paper of a two part series based on an integrated study carried out at Sandia National Laboratories and the State University of New York at Stony Brook. The aim of the study is to develop a more fundamental understanding of plasma-particle interactions, droplet-substrate interactions, deposit formation dynamics and microstructural development as well as final deposit properties. The purpose is to create models that can be used to link processing to performance. Process maps have been developed for air plasma spray of molybdenum. Experimental work was done to investigate the importance of such spray parameters as gun current, auxiliary gas flow, and powder carrier gas flow. In-flight particle diameters, temperatures, and velocities were measured in various areas of the spray plume. Samples were produced for analysis of microstructures and properties. An empirical model was developed, relating the input parameters to the in-flight particle characteristics. Multi-dimensional numerical simulations of the plasma gas flow field and in-flight particles under different operating conditions were also performed. In addition to the parameters which were experimentally investigated, the effect of particle injection velocity was also considered. The simulation results were found to be in good general agreement with the experimental data.

scholarly journals Agglomerate-free BaTiO3 particles by salt-assisted spray pyrolysis

2002 ◽  
Vol 17 (12) ◽  
pp. 3222-3229 ◽  
Author(s):  
Yoshifumi Itoh ◽  
I. Wuled Lenggoro ◽  
Sotiris E. Pratsinis ◽  
Kikuo Okuyama
Keyword(s):  
Spray Pyrolysis ◽  
Residence Time ◽  
Salt Concentration ◽  
Gas Flow ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Particle Residence Time ◽  
20 Nm ◽  
Carrier Gas Flow ◽  
Hot Zone

Optimum conditions for the synthesis of nonagglomerated BaTiO3 particles by salt-assisted spray pyrolysis (SASP) were investigated. The effect of particle residence time in the reactor and salt concentration on the crystallinity and surface morphology of BaTiO3 was examined by x-ray diffraction and scanning electron microscopy. Mixtures of a metal chloride or nitrate salt, dissolved in aqueous precursor solutions, were sprayed by an ultrasonic atomizer into a five-zone hot-wall reactor. By increasing the salt concentration or the particle residence time in the hot zone, the primary particle size was increased, and its surface texture was improved compared to BaTiO3 particles prepared by conventional spray pyrolysis. The SASP-prepared BaTiO3 crystal was transformed from cubic to tetragonal by simply increasing the salt concentration at constant temperature and residence time. Further thermal treatments such as calcination or annealing are not necessary to obtain nonagglomerated tetragonal BaTiO3 (200–500 nm) particles with a narrow size distribution. Increasing the carrier gas flow rate and decreasing the residence time in the hot zone resulted in cubic BaTiO3 particles about 20 nm in diameter.

Plasma Sprayed Alumina-Titania Coatings

1992 ◽  
Vol 271 ◽  
Author(s):  
T. J. Steeper ◽  
A. J. Rotolico ◽  
J. E. Nerz ◽  
W. L. Riggs ◽  
D. J. Varacalle ◽  
...  
Keyword(s):  
Dielectric Strength ◽  
Deposition Efficiency ◽  
Hydraulic Testing ◽  
Fractional Factorial ◽  
Operating Parameters ◽  
Spray Parameters ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
Plasma Sprayed ◽  
Titania Coatings

ABSTRACTThis paper presents an experimental study of the air plasma spraying (APS) of alumina-titania powder using argon-hydrogen working gases. This powder system is being used in the fabrication of heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coatings. The coatings were characterized by hardness and electrical tests, surface profilometry, image analysis, optical metallography, and x-ray diffraction. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. Attempts are made to correlate the features of the coatings with the changes in operating parameters.

The Influence of Temperature and Carrier Gas Flow in the Obtainment of Carbon Nanotubes by Chemical Vapor Deposition

2014 ◽  
Vol 976 ◽  
pp. 169-173
Author(s):  
Alejandro Gómez Sánchez ◽  
Lada Domratcheva Lvova ◽  
Victor López Garza ◽  
Leandro García González ◽  
Pedro González García ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Carrier Gas ◽  
Synthesis Conditions ◽  
Xrd Diffraction ◽  
Carrier Gas Flow

The objective of this study was to evaluate the influence of the synthesis conditions on the characteristics of carbon nanotubes (CNTs), to optimize the process parameters in the growth of CNTs. The CNTs were obtained by Chemical Vapor Deposition (CVD) at 800, 850 and 900 °C and carrier gas flow of 50, 80 and 110 ml/min from ferrocene and benzene during 1 h. The CNTs obtained were analyzed with a field emission scanning electron microscope (FESEM) JSM-7600F. The degrees of crystallinity of the samples were obtained through X-ray diffraction (XRD). The lengths of the CNTs were 3-120 microns and average diameters were 29-72 nm. The highest yields of CNTs were obtained with a flow rate of 80 ml/min and temperature of 850 °C. The diagrams illustrate XRD diffraction peaks corresponding to crystalline phases of graphite, Fe α and cementite (Fe3C). The average CNTs walls were calculated with the Scherrer equation. The CNTs obtained with 50 ml/min carrier flow present an average of 40-42 walls, 80 ml/min-of 33-39 walls and 110 ml/min of 30-34 walls. These facts allow suppose that with a greater flow decreases the number of walls.

The Influence of Injector Geometry and Carrier Gas Flow Rate on Spray Pattern

1997 ◽  
Author(s):  
J.R. Fincke ◽  
W.D. Swank ◽  
D.C. Haggard
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Functionally Graded ◽  
Injection Velocity ◽  
Average Particle ◽  
Gas Flow Rate ◽  
Particle Injection ◽  
Spray Pattern ◽  
Carrier Gas ◽  
Carrier Gas Flow

Abstract The performance (particle velocity and velocity distribution) of a typical injector, and the resulting particle spray pattern for metallic (NiCrAlY) and ceramic (ZrO2) particles are examined as a function of carrier gas flow rate and the effect of varying the geometry immediately upstream of the injector. Injector performance is also examined for a 1:1 mixture of ceramic and metallic particles such as is used in the spraying of functionally graded materials. The upstream geometries tested included a 90° "tee," a 90° elbow, and a straight entrance. The elbow geometry was tested in both "up" and "down" orientation to determine the influence of gravity. The upstream geometry can alter the average particle injection velocity by 10-15% influencing both the spray pattern trajectory and width.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

scholarly journals Analytical study of Buddha sculptures in Jingyin temple of Taiyuan, China

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaojian Bai ◽  
Chen Jia ◽  
Zhigen Chen ◽  
Yuxuan Gong ◽  
Huwei Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Analytical Study ◽  
Energy Dispersive Spectrometry ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Ancient China ◽  
X Ray ◽  
Unique Style ◽  
Scanning Electron

AbstractWith exquisite design and unique style, the painted sculptures of Tutang Buddha and two attendants Buddha in Jingyin Temple are precious cultural heritages of China. The sculpture of Tutang Buddha, which was carved from a mound and painted by ancient craftsmen, was rarely found in ancient China. However, due to natural and human factors, the sculptures were severely damaged. Obviously, they require urgent and appropriate protection and restoration. In this study, samples taken from the sculptures were analysed through multiple analytical techniques, including scanning electron microscopy with energy dispersive spectrometry (SEM–EDS), Raman spectroscopy, X-ray diffraction (XRD), optical microscopy (OM) and granulometry. The analysis results enable us to infer the techniques used by the craftsmen in making the sculptures and provide a reliable evidence for the conservation and future protection of these and similar sculptures.

Sign in / Sign up

Export Citation Format

Share Document