Preparation of hierarchical porous Al2TiO5–mullite ceramics by biological foaming and its microstructural characterization

Abstract

Macroporous Al2TiO5–mullite (AT–M) ceramics with a controllable hierarchical pore structure were prepared by combining biological foaming and flour consolidation using an ice bath to improve pore distribution. The effects of flour, yeast, and solid contents on foaming ability and foam stability were evaluated. In addition, the related effect on pore size distribution, apparent porosity, and mechanical strength of the specimen were systematically investigated. Results indicated that the porosity, compressive strength, and pore structure of macroporous AT–M ceramics could be controlled by adjusting yeast, solid, and flour contents. The solid and flour contents significantly affected the pore size of the specimen. Macroporous AT–M ceramics with a macropore size of 200–400 µm, porosity of 58.77–76.74%, and compressive strength of 3.2–13.98 MPa were obtained. The pore-forming mechanism of the porous ceramics was determined.