Production of cordierite from different magnesium sources

ABSTRACT Master of Science Thesis PRODUCTION OF CORDIERITE FROM DIFFERENT MAGNESIUM SOURCES GÜLSÜM TOPATEŞ Anadolu University Graduate School of Natural and Applied Sciences Ceramic Engineering Program Supervisor: Prof. Dr. Hasan MANDAL 2002, 39 pages Cordierite ceramics are used in thermal applications because of their low thermal expansion coefficient and superior thermal shock resistance. Narrow sintering range, high viscosity and necessity for high temperature for densification are the difficulties in the production of cordierite ceramics compared to other ceramics. In this study, cordierite ceramics were synthesized by using different magnesium sources such as talc, sepiolite, Mg-rich local clay, magnesite and serpentine. Compositions were sintered at different temperatures to examine formation of cordierite. Sintered samples were characterized by X-ray diffraction and scanning electron microscope. Thermal expansion behaviour of cordierite samples were analysed by using dilatometer. In all compositions, a-cordierite formed asa major phase over 1 150°C. High bulk density and nearly zero apparent porosity were achieved at 1200°C by using local clay as a raw material. Thermal expansion coefficient of this sample obtained as 2.64xlO"6/K, 50-800°C. Produced cordierite bodies have a potential in refractory applications where high density and thermal shock resistance are required. Keywords: a-cordierite, magnesium sources, sintering temperature.