Structure and mechanical properties of porous silicon oxycarbide ceramics derived from silicone resin with different filler content

Porous silicon oxycarbide ceramics were obtained through pyrolysis of a new silicone resin filled with its pyrolyzed SiOC powders via a simple self-blowing process. The effects of filler content on the porosity, compressive strength and microstructure of the porous ceramics were investigated. The porosity (total and open) increased firstly and then decreased with the filler content increasing. It was possible to control the total and open porosity of porous ceramics within a range of 66.1–88.2% and 42.7–72.5% respectively, by adjusting the filler content from 0 vol% to 30 vol% while keeping the heating rate fixed at 0.5 °C/min. The compressive strength decreased firstly and then increased with the increasing filler content, and the average compressive strength of the porous ceramics was in the range of 1.1–3.4 MPa. Micrographs indicated that the porous ceramics with the filler content less than 20 vol% had a well-defined open-cell and regular pore structure.