Mechanism of cordierite formation obtained by high temperature sintering technique

Cordierite (2MgO·2Al2O3·5SiO2) is a kind of important ceramic with low thermal expansion coefficient and low dielectric constant. In this study, the influence of raw material compositions and various sintering temperatures on the synthesis mechanism and reaction path of cordierite were studied. The results reveal that the binary compounds forsterite and magnesia-alumina spinel are firstly generated in the low-temperature section while using pure single oxide materials. Then, forsterite and magnesia-alumina spinel are respectively combined with Al2O3 and SiO2 to form cordierite. The reaction of magnesia-alumina spinel with SiO2 to form cordierite requires a higher temperature. The addition of CaO and TiO2 tends to form low melting point substances, thus promoting the formation of cordierite phase. This study has a certain guiding significance for the cordierite synthesizing from natural minerals and solid wastes.