Chemical vapor condensation

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... 

Ullrafine particles (UFPs) of metal and semiconductor nitrides have been synthesized by two major techniques one is the reactive gas condensation method, and the other is the chemical vapor condensation method. The former is modified from the so-called gas condensation method (or gas-evaporation method) (13), and a surrounding gas such as N2 or NII2 is used in the evaporation chamber instead of inert gases. Plasma generation has been widely adopted in order to enhance the nitridation in the particle formation process. The latter is based on the decomposition and the subsequent chemical reaction of metal chloride, carbonate, hydride, and organics used as raw materials in an appropriate reactive gas under an energetic environment formed mainly by thermal healing, radiofrequency (RF) plasma, and laser beam. Synthesis techniques are listed for every heal source for the reactive gas condensation method and for the chemical vapor condensation method in Tables 8.1.1 and 8.1.2, respectively. 

Table 8.1.2 Synthesis Techniques of Ultrafine Nitride Particles by Chemical Vapor Condensation...

Fig. 8.1.9 Schematic illustration of the apparatus for thermally activated chemical vapor condensation A, reactor B, furnace C, FeCE D, electrostatic collector E, thermocouple. (From Ref. 48. Reprinted with permission of the Chemical Society of Japan.)...

Nanomaterials are also prepared by chemical vapor deposition (CVD) or chemical vapor condensation (CVC). In these processes, a chemical precursor is converted to the gas phase and then it undergoes decomposition to generate the nanoparticles. These products are then subjected to transport in a carrier gas and collected on a cold substrate, from where they are scraped and collected. The CVC method may be used to produce a variety of powders and fibers of metals, compounds, or composites. The CVD method has been employed to synthesize several ceramic metals, intermetallics, and composite materials. 

X. Dong, C. Choi, B. Kim, Chemical synthesis of Co nanoparticles by chemical vapor condensation, Powder Technol. 113 (2002) 75-79. 

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... 

Chemical vapor condensation (CVC) was applied by Lee for the production of Ti02 nanoparticles by decomposition of Ti(0)(acac)2. In the temperature range of 800-1000 °C hollow-shell nanoparticles (10-40 nm diameter, 4-5 nm thick) of anatase-rutile mixed phases were obtained. The formation of the hollow structure is a result of the competition... 

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). 

Choi CJ, Kim BK, Kim JC, Wang ZH, Zhang ZD. 2003. Characterization and magnetic properties of carbon-coated cobalt nanocapsules synthesized by the chemical vapor-condensation process. Carbon 47 1751-1758. 

Choi C, Dong X, Kim B. Characterization of Fe and Co nanoparticles synthesized hy chemical vapor condensation. Scr Mater 2001 44 2225-9. 

Attar A, Halali M, Sobhani M, Ghandehari RT. Synthesis of titanium nano-particles via chemical vapor condensation processing. J Alloys Compd 2011 509 5825-8. 

Wang Z, Zhang Z, Choi C, Kim B. Structure and magnetic properties of Fe (C) and Co (C) nanocapsules prepared by chemical vapor condensation. J Alloys Compd 2003 361 289-93. 

Dong X, Choi C, Kim B. Structural and magnetic characterization of Fe nanoparticles synthesized by chemical vapor condensation process. J Appl Phys 2002 92 5380-5. 

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