A low-temperature fabrication route for enhancing mechanical properties and corrosion resistance of porous mullite ceramics through homogeneously mullite sol-coating method

Porous ceramics were fabricated by mullite sol-coated mullite powder (homogeneously sol-coated) through sol-gel method using expanded polystyrene (EPS) as pore former. In this work, mullite formed in the coating layer was characterized by XRD. The effect of mullite sol coating content and sintering temperature on the microstructure and mechanical properties of porous mullite ceramics was investigated. Homogeneously sol-coated sample sintered at 1450 degrees C with 30 wt.% mullite sol coating exhibited a remarkable flexural strength of 24 MPa at 53% apparent porosity. It showed that the interlocking structure formed from homogeneously sol-coated sample was helpful to enhance the mechanical strength and thermal alkali corrosion resistance of the porous mullite ceramics.