Influence of mechanical activation on combustion synthesis of fine silicon carbide (SiC) powder

The influence of mechanical activation of powder mixtures of Si and C, via high energy attrition milling (up to 12 h), on combustion synthesis of SiC was experimentally investigated. β-SiC fine powder was successfully fabricated in 1.0 MPa N2 atmosphere without other additional treatments, such as preheating, electric action, or chemical activation. Relatively weak peaks of α-SiC, α-Si3N4 and Si2ON2 were also found in the final products. The experimental results and their theoretical treatment showed that mechanical activation via high energy ball-milling provides to the initial Si/C powder mixture extra energy, which is needed to increase the reactivity of powder mixture and to make possible the ignition and the sustaining of combustion reaction to form SiC.

Fine sized powders of β-SiC was fabricated by combustion reaction of mechanical activation Si and C powder successfully. The average particle size of the formed SiC powders is about 400 nm. The influence mechanism of high energy attrition ball-milling on combustion synthesis of SiC powder including particle size, amorphization, and inner strain in the crystallites was studied comprehensively.X-ray diffractograms of the powder mixture, benignly mixed and after ball-milling in Ar and N2 atmospheres (atmospheric pressure) for different times.Figure optionsDownload as PowerPoint slide