SiC is the representative engineering ceramic, which is thermally stable and has excellent mechanical properties on high temperature environments. Another engineering ceramic, B4C also has distinguished mechanical properties with low density, and facilitate each other’s sintering with SiC [1]. SiC and SiC-based composites are actively applied to industries with extreme thermal environment like aerospace and turbine materials, however its actual high temperature properties show broad range of deviation by pore, crack, and oxide in the material. Therefore fabrication process and control affects greatly on obtaining target properties.

SiC-based material from high concentration SiC slurry could minimize the above problems that we fabricated ultra-high concentration slurry (up to over 70 vol%) to make green body and later densify by polymer infiltration and pyrolysis (PIP) method (89 % relative density). Along with optimizing slurry dispersion and viscosity with drying control, which enables fabrication of dense SiC and SiC-baced ceramic matrix composite (CMC) with improved high temperature properties.

Cf/SiC composite fabricated by 66 vol% SiC slury showed high temperature flexural strength of 433.6 MPa at 1750 ℃ and 541.5 MPa at 2000 ℃ (Figure 1). After further investigation, SiC slurry with small amount of B4C shows better dispersion and fluid characteristics than SiC slurry without B4C additives. SiC slurries of concentration similar or higher than 66 vol% were used to make sintered body and composites then mechanical and thermal properties at high temperatures were examined by methods like high temperature bending test.