Freeze casting fabrication of porous ZrC/SiC decorated with SiC whiskers using polymeric precursors

Abstract

SiC whisker-modified porous ZrC/SiC ceramics were fabricated by applying freeze casting and pyrolysis techniques on a mixture of a zirconium-containing polymer and polycarbosilane. This process does not involve metal catalysts or cross-linking treatment as in conventional methods. The porous ZrC/SiC ceramics, with high porosity (85.84%) and large pore size (22.5 ± 2.5 μm), facilitated the in-situ growth of the SiC whiskers according to the vapor–solid (V-S) model. The gaseous SiO and CO, which were generated by the carbothermal reduction procedure, were the key raw materials for synthesizing SiCw. After the pyrolysis process at 1550 °C, the mixed precursor was fully converted to ZrC and SiC.