Microstructure and mechanical performance of porous mullite ceramics added with TiO2

Porous mullite samples were manufactured using granular mullite powders as major materials, and TiO2 as the additive agent. Influences of TiO2 contents on rheological characteristics of slurries, and microstructure and bending strength at 25-1400 degrees C of final porous mullite products were investigated. Adding appropriate content of TiO2, a large amount of columnar mullite with mean length of 23.7 mu m and the length-to-diameter ratio of 6.7 was in-situ formed, which could improve the mechanical performance of the resultant porous samples. The bending strength at 25 degrees C of porous products containing 67% porosity fabricated by using 7 wt% TiO2 reached 12.5 MPa, and its bending strength at 1200 degrees C remained as high as 6.1 MPa.