Effect of Al(OH)3 content on the microstructure and strength of porous cordierite-mullite ceramics prepared by an in-situ pore forming technique

Abstract

Five porous cordierite-mullite ceramics with similar porosity and different neck characteristics were prepared from Al(OH)3, magnesite, silica and clay using an in-situ pore-forming technique. The phase composition, pore and neck characteristics and strength of the porous ceramics were investigated by an X-ray diffractometer (XRD), a scanning electron microscopy (SEM) and a microscopy measured method, etc. The experimental results showed that Al(OH)3 content had a significant effect on the pore size distribution and neck characteristics (neck size distribution, total value of neck size and phase composition) and then affecting the strength. With an increase in Al(OH)3 content, the median pore size decreased, the total length of necks and the uniformity of neck size increased, also the mullite content of necks increased, resulting in the increase of strength of the porous cordierite-mullite ceramics. When the Al(OH)3 content was 64.9 wt%, the porous cordierite-mullite ceramics had the best performance of high apparent porosity of 45.1 % and high compressive strength of 55.9 MPa.