Synthesis of Cordierite with Low Thermal Expansion Coefficient

Cordierite is an excellent material with good thermal shock resistance and used at high temperature for its low thermal expansion coefficient. Cordierite ceramics were prepared by using talc, alumina and kaolin clay as starting materials. The thermal expansion coefficient, phase composition and microstructure were studied and the results showed that: in order to get samples with low thermal expansion coefficient, the optimum chemical composition was a little rich in Al2O3 compared with the theoretical composition, the optimum sintering temperature was 1350°C, and adding 10% starch as pore-forming agent could effectively decreased the thermal expansion coefficient of the samples even to 0.8×10-6/°C. The samples contained majority of cordierite phase, with trace mullite and glass, the acicular cordierite crystals in samples developed very well and there were 10% starch powder used as pore-forming agent in formula. All these were the reasons to decrease the thermal expansion coefficient of cordierite material.