Study on Lower Thermal Expansion Coefficient of Synthetic Cordierite Materials

Cordierite was synthesized using kaolin, talc and magnesia as raw materials. Effect of firing temperature, content of(silicon, aluminum, magnesium) in formulation and type of kaolin was studied on the thermal expansion coefficient of synthetic cordierite. The result shows that the lowest thermal expansion was 1.24×10-6/℃ of the experimental synthetic cordierite material, Formulas for the experiments were 82.4 wt% 1# kaolin, 9.3 wt% talc and 8.4 wt% magnesium oxide. Lower expansion cordierite can be synthesized by increasing synthesis temperature appropriately, but too high temperature brings about the opposite result. Too much or too little silicon, aluminum or magnesium leads to the synthetic cordierite with larger thermal expansion coefficient because of the formation of high expansion crystal phases.