Nano-SiC ceramic sintering at ultra-high pressure and high temperature

High-density Sic ceramics doped with 2wt% Al2O3 additives were fabricated by ultra-high pressure and high temperature technique (4.5GPa,1250 degrees C,20min). The structures, grain size, lattice parameters, chemical component, morphology and mechanical property of the sintered Sic ceramics were characterized by X-ray diffraction (XRD), X-ray photoelectron energy spectroscope (XPS), scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX) and nano impress indenter. The results show that nano-SiC ceramic is fully densified by ultra-high pressure technique at, relative low temperature (1250 +/- 50 degrees C). No phase transfer or holes is found in the sintered nano-SiC ceramic. The hardness and elastic modulus of the sintered SiC ceramic with grain size of 22nm and lattice parameters of 4.355 angstrom are 33.7GPa and 407GPa, respectively.