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.

Scale-up of Nanoparticle Synthesis by Flame Spray Pyrolysis: The High-Temperature Particle Residence Time

2014 ◽  
Vol 53 (26) ◽  
pp. 10734-10742 ◽  
Author(s):  
Arto J. Gröhn ◽  
Sotiris E. Pratsinis ◽  
Antoni Sánchez-Ferrer ◽  
Raffaele Mezzenga ◽  
Karsten Wegner
Keyword(s):  
High Temperature ◽  
Spray Pyrolysis ◽  
Residence Time ◽  
Scale Up ◽  
Nanoparticle Synthesis ◽  
Flame Spray Pyrolysis ◽  
Flame Spray ◽  
Particle Residence Time

scholarly journals Synthesis of Nanowires by Spray Pyrolysis

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Kalyana C. Pingali ◽  
Shuguang Deng ◽  
David A. Rockstraw
Keyword(s):  
Spray Pyrolysis ◽  
Metallic Nanoparticles ◽  
Gas Flow ◽  
Nickel Chloride ◽  
X Ray ◽  
Carbon Coated ◽  
Morphological Differences ◽  
Carrier Gas Flow ◽  
Carbon Nanowires ◽  
Binary Nanoparticles

Nanowires of carbon as well as nickel-carbon (Ni-C) were synthesized by spray-pyrolysis. The carbon nanowires were synthesized using methanol as a precursor while the Ni-C nanowires were obtained by using nickel chloride methanol solution as feed. It was found that low argon carrier gas flow rates (<100 cm3/min) and suitable reaction temperatures (∼700∘C) were found to be critical for the formation of wired structures. The formation of nanowires was quite sensitive to reaction temperature. Nanowires could not form at temperatures higher than900∘C in the presence of hexane. Ruthenium chloride and nickel chloride dissolved in hexane and methanol resulted in carbon coated binary metallic nanoparticles. Morphological differences of carbon nanowires, Ni-C wires and carbon coated binary nanoparticles were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). The formation mechanism for the wired structures is proposed to explain the structural results obtained.

Synthesis and Study of Carbon Nanotubes by the Spray Pyrolysis Method Using Different Carbon Sources.

2015 ◽  
Vol 1752 ◽  
pp. 31-38
Author(s):  
Beatriz Ortega Garcia ◽  
Oxana Kharissova ◽  
Francisco Servando Aguirre-Tostado ◽  
Rasika Dias
Keyword(s):  
Carbon Nanotubes ◽  
Spray Pyrolysis ◽  
Gas Flow ◽  
Carbon Sources ◽  
Spray Pyrolysis Method ◽  
Solution Flow ◽  
Synthesis Time ◽  
Transmission Electron ◽  
Carrier Gas Flow

ABSTRACTAccording to the reports of Z.E. Horvath et al [1] and Liu Yun-quan et al [5], carbon nanotubes can be synthesized by spray pyrolysis from different carbon sources (n-pentane, n-hexane, n-heptane, cyclohexane, toluene and acrylonitrile) and several metallocene catalysts (ferrocene, cobaltocene and nickelocene). This paper describes two different existing methods for growth of carbon nanotubes and the influence of applied parameters (oven temperature, synthesis time, catalyst concentration, carrier gas flow and solution flow) on the CNT's morphology. Also, a possible influence of number of carbons in carbon sources and structures of their compounds (linear or aromatic) on properties of formed carbon nanotubes. Transmission Electron Microscopy (TEM), Infrared Spectroscopy (FTIR) and Raman spectroscopy were applied for characterization of obtained materials.

scholarly journals Selective Production of Terephthalonitrile and Benzonitrile via Pyrolysis of Polyethylene Terephthalate (PET) with Ammonia over Ca(OH)2/Al2O3 Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 436 ◽  
Author(s):  
Lujiang Xu ◽  
Xin-wen Na ◽  
Le-yao Zhang ◽  
Qian Dong ◽  
Guo-hua Dong ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Residence Time ◽  
Gas Flow ◽  
Pyrolysis Temperature ◽  
Fast Pyrolysis ◽  
Carboxyl Group ◽  
Gas Flow Rate ◽  
Ammonia Content ◽  
Catalyst Dosage ◽  
Carrier Gas Flow

A series of Ca(OH)2/Al2O3 catalysts were synthesized for selectively producing N-containing chemicals from polyethylene terephthalate (PET) via catalytic fast pyrolysis with ammonia (CFP-A) process. During the CFP-A process, the carboxyl group in PET plastic was efficiently utilized for the selective production of terephthalonitrile and benzonitrile by controlling the catalysts and pyrolysis parameters (e.g. temperature, residence time, ammonia content). The best conditions were selected as 2% Ca(OH)2/γ-Al2O3 (0.8 g), 500 °C under pure ammonia with 58.3 C% terephthalonitrile yield and 92.3% selectivity in nitriles. In addition, 4% Ca(OH)2/ Al2O3 was suitable for producing benzonitrile. With catalyst dosage of 1.2 g, residence time of 1.87 s, pyrolysis temperature of 650 °C and pure ammonia (160 mL/min carrier gas flow rate), the yield and selectivity of benzonitrile were 30.4 C% and 82.6%, respectively. The catalysts deactivated slightly after 4 cycles.

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.

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.

PEMBUATAN NANOPARTIKEL SENG OKSIDA (ZNO)MENGGUNAKAN PROSES FLAME ASSISTED SPRAY PYROLYSIS (FASP)

EKUILIBIUM ◽  
2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Agus Purwanto
Keyword(s):  
Spray Pyrolysis ◽  
Flow Rate ◽  
Zno Nanoparticles ◽  
Gas Flow ◽  
Point Of View ◽  
Carrier Gas ◽  
Flame Reactor ◽  
Mean Size ◽  
The Mean ◽  
Carrier Gas Flow

<p>Abstract: ZnO nanoparticles have been succesfully produced using Flame Assisted Spray<br />Pyrolysis (FASP) method. Burner type was a premixed flame reactor that used LPG as a fuel<br />and air as oxidizer because of an economical point of view. Zn(NO<br />3<br />)2<br />was used as a precursor<br />source for ZnO nanoparticles production. The flow rates of carrier gas during ZnO nanoparticles<br />fabrication were 5 L/menit, 7 L/menit, and 9 L/menit. To get the information about size and<br />shape of ZnO nanoparticles was characterized using Scanning Electron Microscope (SEM) and<br />X-Ray Diffractometry (XRD). The results showed that the higher carrier gas flow rate, the bigger<br />size of ZnO nanoparticles. By using the flow rate of carrier gas at 5 L/min, the mean size of ZnO<br />nanoparticles was about 80 nm. ZnO nanoparticles at carrier gas of 5 L/min were hexagonal<br />zincite crystalline structure and XRD were about 30,62 nm<br />Keywords: Flame Assisted Spray Pyrolysis, nanoparticles, ZnO, LPG, SEM, XRD</p>

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.

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