Synthesis and sintering of nanocrystalline SiC ceramic powders

Abstract This paper reports a simple route to synthesize nanocrystalline silicon carbide (SiC) ceramic powders via the direct reaction of silicon powders with carbon black in a temperature-programmed muffle furnace. The mixing powders of silicon and carbon black were loaded in a alumina crucible, and then the crucible was sealed with some materials to prevent oxidization. The effect of reaction temperature on the phase of the product powders was investigated. FESEM and TEM images showed that the SiC nanopowders were spherical and had an average particle size of 48.56 nm. The sintering activities of the SiC nanopowders and commercial SiC fine powders were also investigated by hot-pressing sintering. SiC nanoceramic sintered at 1850 °C exhibited a high relative density (up to 99.2%) and a high flexural strength of 580 MPa, which exhibits better sintering activity of synthesized SiC nanopowders.