Preparation of Porous SiC Ceramic by Liquid Si Infiltration and Mixture Acid (HNO3+HF) Etching

Abstract:

Porous SiC was prepared by liquid Si infiltration and mixture acid (HNO3+HF) etching. SEM observation reveals that the porous SiC possesses irregular, interconnected and porous morphology, which comes from the porous carbon perform derived by filter paper and phenolic resin. Open porosity of the porous SiC is up to 62%. The bending strength and the fracture toughness of the porous SiC are lower than that of SiC/Si composites. The etching mechanism of free Si can be explained by the repeated oxidation-etching process