Combustion flame-chemical vapor

Rapid solidification and devitrification of amorphous metals and metallic glasses Combustion-flame chemical vapor condensation processes (Kear) Induction-heating chemical vapor condensation processes DC and RF magnetron sputtering, inclusive of the method of thermalization Laser ablation methods Supercritical fluid processing... 

Combustion-flame chemical vapor condensation processes (Kear)... 

B. Combustion Flame-Chemical Vapor Condensation Process... 

The CF-CVC (combustion flame-chemical vapor condensation) process developed by Kear and co-workers (Skandan et al., 1996 Tompa et al., 1999) is a continuous process using the equipment shown in Fig. 1. The starting materials are metal complexes that can be vaporized and fed into a flat flame, which immediately converts the compounds to nanostructured metal oxides. The particle dilution is controlled to prevent agglomeration in a hot state... 

Fig. 1. The CF-CVC (combustion flame chemical vapor condensation) (Skandan et al., 1996 Tompa et al., 1999) for producing nanostructured materials.

Collagen, human body, 132-133 Combustion flame-chemical vapor condensation (CF-CVC) nanostructured materials, 10-11 schematic, 10 7T-Complexation sorbents description, 108-109 effects of cation, anion, and substrate, 112-113... 

B.K. Kim, G.G. Lee, H.M. Park, N.J. Kim, Characteristics of nanostructured Ti02 powders s3mthesized by combustion flame-chemical vapor condensation process , Nanostructured Materials, 12, 637-640, (1999). 

Building on our experience with IGC and CVC, we have replaced the heat source by a flame in the Combustion Flame - Chemical Vapor Condensation (CF-CVC) technique. This technique offers several advantages over previous methods and has the potential to continuously generate non-agglomerated powders at high rates typical for industrial processes. These advantages have been exploited in other research and commercial flame synthesis processes for the production of diamond, carbon black, other particulates, and a variety of thin films, but not to date for the large scale production of nanoscale powders. 

Stagnation flows represent a very important class of flow configurations wherein the steady-state Navier-Stokes equations, together with thermal-energy and species-continuity equations, reduce to systems of ordinary-differential-equation boundary-value problems. Some of these flows have great practical value in applications, such as chemical-vapor-deposition reactors for electronic thin-film growth. They are also widely used in combustion research to study the effects of fluid-mechanical strain on flame behavior. 

E. Meeks, R.J. Kee, D.S. Dandy, and M.E. Coltrin. Computational Simulation of Diamond Chemical Vapor Deposition in Premixed C2H2/O2/H2 and CH4/02-Strained Flames. Combust. Flame, 92 144—160,1993. 

The chemical dynamics, reactivity, and stability of carbon-centered radicals play an important role in understanding the formation of polycyclic aromatic hydrocarbons (PAHs), their hydrogen-dehcient precursor molecules, and carbonaceous nanostructures from the bottom up in extreme environments. These range from high-temperature combustion flames (up to a few 1000 K) and chemical vapor deposition of diamonds to more exotic, extraterrestrial settings such as low-temperature (30-200 K), hydrocarbon-rich atmospheres of planets and their moons such as Jupiter, Saturn, Uranus, Neptune, Pluto, and Titan, as well as cold molecular clouds holding temperatures as low as 10... 

Chemical Vapor Deposition (CVD) has been defined as a materials synthesis process whereby constituents of the vapor phase react chemically near or on a substrate surface to form a solid product. With these traditional processes a reaction chamber and secondary energy (heat) source are mandatory making them different from the Combustion CVD process. Numerous flame-based variations of CVD have been used to generate powders, perform spray pyrolysis, create glass forms, and form carbon films including diamond films. 

M. Oljaca, H.L. Luten, T. Tomov, and T. Metzger, BST Thin Eilms by Combustion Chemical Vapor Deposition, Dependency of Materials Properties on Flame Characteristics, Combustion Flame, to be submitted. 

Analyte Atomization and Ionization By the time the analyte atoms and ions reach the observation point in the plasma, they have spent about 2 ms in the plasma at temperatures ranging from 6000 to 8000 K. These times and temperatures are two to three times greater than those attainable in the hottest combustion flames (acetylene/nitrous oxide). As a consequence, desolvation and vaporization are essentially complete, and the atomization efficiency is quite high. Therefore, there are fewer chemical interferences in ICPs than in combustion flames. Surprisingly, ionization interference effects are small or nonexistent because the large concentration of electrons from the ionization of argon maintains a more-or-less constant electron concentration in the plasma. 

In this paper we present a new technique for the synthesis of carbon film with carbynoid structures. The basis of the method described here consists of a combustion reaction between oxygen and acetylene and particular parameters for flame conditions. The flame volume can be considered as the reaction chamber as in conventional chemical vapor deposition (CvD) or physical vapor deposition (PVD) methods. This technique provides a method of synthesizing carbyne at high growth rates and of obtaining better crystals. 

An important topic of research is the introduction of the catalyst in the microreactor. In brief solid catalysts can be incorporated on the interior of micromachined reaction channels, prior to or after closure of the channel, by a variety of strategies anodic oxidation, plasma-chemical oxidation, flame combustion synthesis, sol-gel techniques, impregnation, wash coating, (electro-)plating, aerosols, brushing, chemical vapor deposition, physical vapor deposition and nanoparticle deposition or self-assembly. Some of these methods can be applied in combination with photolithography or shadow masking. 

CCVD combustion chemical vapor deposition MOCVD mettil-organic-assisted CVD PECVD plasma-enhanced CVD FACVD flame-assisted CVD AACVD aerosol-assisted CVD ESAVD electrostatic-atomization CVD LPCVD low-pressure CVD APCVD atmospheric-pressure CVD PACVD photo-assisted CVD TACVD thermtil-activated CVD EVD electrochemical vapor deposition RTCVD rapid thermal CVD UHVCVD ultrahigh-vacuum CVD ALE atomic-layer epitaxy PICVD pulsed-injection CVD... 

In fact diamond can also be formed at low pressure. With the Chemical Vapor Deposition technique (CVD) diamond can be forced to grow on a substrate surface. As a rule a gas mixture, containing a hydrocarbon and hydrogen, is thermally activated by a combustion flame or plasma technique. Atomic hydrogen and carbon containing radicals are formed, a gas from which diamond starts to grow at a low pressure. In ref [39.8] a nanocrystalline diamond coating of this type is described. Deposition temperature was 900°C. 

RufB, Behrendt F, Deutschmann O, Kleditzsch S, Warnatz J Modeling of chemical vapor deposition of diamond films from acetylene-oxygen flames, Proc Combust Inst 28 1455-1461, 2000. 

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