Mechanism of combustion synthesis of silicon carbide

Abstract

The mechanism of self-propagating high-temperature synthesis (SHS) or combustion synthesis of SiC has been investigated using pellets consisting of silicon and carbon powders. The combustion reaction was initiated by rapidly heating the pellet on a graphite strip. The reaction products were analyzed using scanning and transmission electron microscopy, x-ray diffraction, and Raman spectroscopy. The results show that it is possible to produce β-SiC without any residual silicon and carbon. Occasionally, a very small number density of α-SiC precipitates embedded in the β-SiC matrix was observed. Based upon the microstructural features, it is proposed that the formation of SiC involves the dissolution of carbon into liquid silicon, diffusion of C into liquid silicon, and subsequent precipitation of SiC. The size of the SiC crystallites is determined by the diffusion coefficient of carbon in liquid silicon and the time available for SiC precipitation. The activation enthalpy for the SHS process is estimated to be 59±3 kcal/mol.

Improvement of permittivity of SiC with Al doping by combustion synthesis using Al2O3

“…of SiC powder, the combustion synthesis (CS) has many advantages: (1) easy generation of higher purity products; (2) relatively simple and energy efficient; (3) synthesis of novel materials with unique properties [25]. It is interesting that the CS process can produce novel phases with unique properties in materials due to high thermal gradient and rapid cooling rate [26].…”

Synthesis and characterization of 3C and 2H-SiC nanocrystals starting from SiO2, C2H5OH and metallic Mg

“…Various methods have been developed for the synthesis of SiC nanocrystals, such as the carbothermal reduction reaction [4,5], chemical vapor reaction [6], sol-gel [7,8], self-propagating high temperature synthesis [9], autoclave route [10][11][12][13][14][15] and so on. Among these methods, prepare SiC in an autoclave is one of the effective routes at low temperature, such as the reactant systems: SiCl 4 -Na-C [10] or SiCl 4 -Na-C 6 Cl 6 [11] at 600 • C, SiCl 4 -Na-CCl 4 at 400 • C [12], SiCl 4 -Na-K-CBr 3 H at 130 • C [13], or sulfur-assisted reduction route (Si-S-Na-C 2 Cl 4 ) at 130 • C [14].…”

A cost-effective approach to improve dielectric property of SiC powder

“…However, the cost of two methods is very high. Compared with these methods, the combustion synthesis (CS) has many advantages: (1) easy generation of higher purity products; (2) relatively simple and energy efficient; (3) synthesis of novel materials with unique properties [7,8]. It is interesting that the CS process can produce novel phases with unique properties in materials due to high thermal gradient and rapid cooling rate.…”