A simple pressing route to closed-cell microcellular ceramics

A simple pressing process using a polysiloxane and expanded microspheres for fabricating closed-cell microcellular ceramics is demonstrated. The strategy for making the microcellular ceramics involves: (i) forming preceramic foams using a mixture of preceramic polymer and expanded microspheres by pressing, (ii) cross-linking the formed body, and (iii) transforming the body into microcellular ceramics by pyrolysis. By controlling the microsphere content, it was possible to adjust the porosity ranging from 70% to 87%. The compressive strength of the microcellular ceramics with ∼70% porosity was ∼100 MPa.