Preparation of porous Al2TiO5 ceramics reinforced by in situ formation of mullite whiskers

Due to the low thermal expansion coefficient and high temperature resistance, porous Al2TiO5 ceramic is a promising candidate for use in high-temperature gas purifier, diesel tail gas processor and catalyst support. In this paper, Al2TiO5-based porous ceramics reinforced by in situ formation of mullite whiskers were fabricated by reaction sintering method using γ-AlOOH, TiO2, SiO2 and AlF3 as raw materials, Fe2O3 as modifying agent, respectively. Results show that apparent porosity of the composite porous ceramics is increased from 33.3% to 45–52% when the raw materials for mullite were added, and the compressive strength of the porous ceramic is above 11 MPa. The in situ synthesized mullite whiskers, with the size of 0.5–0.6 μm in diameter and 6–8 μm in length, formed interlocking structure in the pores of Al2TiO5-based porous ceramics, which is beneficial to improve the strength and increase the specific surface area of the porous ceramics.