Influence of fabricated process on mechanical properties of porous SiC-particle/ Si₃N₄ composites

In this paper, the mechanical properties of porous Si₃N ₄SiC composite prepared by different forming method (uniaxial pressing and gel-casting) were compared. Using gel-casting and two steps sintering technology, the porous SiC-particle/Si₃N₄ composites with a high strength, uniform structure and a relative high porosity were obtained by adding a little amount of nano carbon in slurry. The flexural strength of optimized material reaches to 100MPa and its porosity is more than 60%. But using uniaxial pressing and sintering at N₂ atmosphere, because the green bodies have the high density, and the density distribution of a powder compact was not uniform, the flexural strength is not high, and at the same time, the microstructure is not uniform also.