Porous mullite ceramics were fabricated from pyrolysis of nanometer alumina powders filled silicone resin. At 1573 K, the mixture of nanometer γ-Al2O3 and silicone resin can be entirely transformed to mullite in air. The effects of shaping pressure on microstructure and mechanical property were investigated. Increasing shaping pressure leads to decrease in open porosity and average pore size, narrower pore size distribution, and improvement in flexural strength. With a shaping pressure of 43 MPa, nanoporous mullite ceramics with an average pore size of 50 nm can be obtained, showing 33% in open porosity and 42 MPa in flexural strength. The microstructure of porous mullite ceramics consists of dense region and loose region.
