Kinetic studies on ?-SiC formation from homogeneous precursors

Kinetics of carbothermal reduction synthesis of beta silicon carbide

“…4ks0csi0 k =: -P C Shimoo et al (1990) Visromi and Himmel (1978) rates as shown by the data of Kuznetsova et al (1980) and Viscomi and Himmel(l978). Carbon from pyrolyzed polymers is generally very reactive as indicated by the rates reported by Ono and Kurachi (1991) and Shimoo et al (1990). The reaction rates estimated for previously reported carbon blacks (Blumenthal et al, 1966;Kuznetsova et al, 1980), using the rate equation derived in this work, are slightly lower than those reported by the previous investigators.…”

“…Lee et al (19761, Lee and Cutler (1975), Kennedy and North (1983), and Krstic (1992) found reaction 1 to be controlled by the generation of SiO, reaction 2, while Viscomi and Himmel (1978) reported the reduction of SiO to Sic, reaction 3, to be rate-controlling. Several researchers (Klinger et al, 1966;Ono and Kurachi, 1991) have reported nucleation growth to be of importance, particularly for temperatures near or above the transformation temperature of quartz to cristobalite (Klinger et al, 1966). Carbon diffusion effects have been reported to be important in several studies (Ono and Kurachi, 1991;van Dijen and Metselaar, 1991).…”

“…Several researchers (Klinger et al, 1966;Ono and Kurachi, 1991) have reported nucleation growth to be of importance, particularly for temperatures near or above the transformation temperature of quartz to cristobalite (Klinger et al, 1966). Carbon diffusion effects have been reported to be important in several studies (Ono and Kurachi, 1991;van Dijen and Metselaar, 1991). Van Dijen and Metselaar (1991) have recently rejected an SiO intermediate and suggested that overall reaction (Eq.…”

TGA-DSC-MS analysis of silicon carbide and of its carbon-silica precursor

“…Another important parameter for the process of SiC synthesis is the time of full silica conversion into silicon carbide. Several groups have performed various kinetic studies on SiC synthesis applying different reaction conditions and carbon/silica precursors (see, for instance, [12,[14][15][16][17][18]). Although the activation energies reported varied from 230 to 550 kJ/mol, there is a general consistency that the reaction rate increases when the temperature is higher, the precursor particle size is finer, and CO is removed.…”

Synthesis of SiC-TiC Powders by Pyrolysis of Phenolic Resin-Alkoxides Hybrid Precursors.

“…The mechanism of such carbothermic reduction is, however, not simple, because the material carbon and silica particles merely contact by points on surface in usual cases.1)-7) We have investigated the simultaneous condensation reaction of water soluble liquid phenol resin and tetraethyl orthosilicate (TEOS) in concentrated mixtures and their pyrolysis process to overcome such heterogeneous mixing between the carbon sources and silica sources.8)-11) This process is based on the method developed by Kurachi in 1991.12), 13) This method, in addition, allows the mixing of various alkoxides in the starting mixtures, which will be incorporat ed into organic-inorganic network during the condensation reaction. Effect of borate addition into the resin-TEOS start ing precursor has been investigated from the viewpoint of the SiC crystallite growth during the carbothermic reduc tion process at 1873K.…”