LI Hao ¹, LI Cuiwei ¹, WANG Chang’an ²
(1. School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China; 2. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China)

Abstract: Basic magnesium carbonate, alumina and silica were used as raw materials to in-situ synthesize porous cordierite ceramics by using foam gelcasting method. The formation mechanism of cordierite during sintering was explored by using TG-DTA, XRD and SEM. It was demonstrated that magnesia produced due to the decomposition of the basic magnesium carbonate reacted with alumina to form magnesia aluminum spinel. Quartz transformed to cristobalite and finally cordierite was formed through the reaction of magnesia-aluminum spinel and cristobalite. Porous cordierite ceramics with different properties could be obtained by adjusting the processing parameters. When the solid content was 20 vol.% and the sintering temperature was 1455 ℃, the sample exhibited an total porosity of 86% and a compressive strength of 2.55 MPa, achieving a high match degree between high porosity and high strength. This achievement offered a useful guidance for the preparation and application of lightweight high-strength porous ceramics.
Key words: cordierite; porous ceramics; compressive strength; reaction mechanism