Porous cordierite ceramics prepared by foam-gelcasting technique: Phase evolution and properties

Abstract

Porous cordierite ceramics with a single phase, high porosity and high strength were in-situ prepared using periclase, alumina and silica powders as raw materials by foam-gelcasting technique firstly. The reaction mechanism of preparing process was investigated via TG-DTA, X-ray diffraction, scanning electron microscope and electron energy disperse spectroscopy. The results confirmed that Mg(OH)2 was formed during the preparation of green body and cordierite was formed at 1325 °C through the intermediate phases of cristobalite and MgAl2O4 spinel. Samples with different performance have been fabricated by changing experimental parameters. Through altering holding time, sintering temperature and solid content in a certain scale, high porosity (83.9–89.2%), low bulk density (0.28–0.42 g/cm3) and high compressive strength (0.9–4.7 MPa) were obtained. The SEM images showed that the pore structure of the as-prepared material was multiscale, the cordierite grains were irregular and the grain size was below 5 μm. The method used in this paper shows great promise for preparing porous cordierite ceramics with single phase, high porosity and high strength.