Synthesis of plate-like cordierite using a small amount of H3BO3 flux

This work aimed to prepare high-purity, plate-like cordierite powder at a lower cost. Kaolin, talc and alumina were used as the starting materials for cordierite synthesis, and only a small amount of boric acid (H3BO3) was used as the flux. Despite the limited amount of liquid phase formed, the addition of H3BO3 could effectively promote the formation of plate-like cordierite polycrystals, which might be related to the gas-phase-mass transfer of molten boron trioxide (B2O3) at high temperatures and the selective adsorption of [BO3] on different crystal planes during crystallization. Moreover, it is necessary to closely control the calcining temperature, as the morphological development of cordierite polycrystals was sensitive to temperature. Plate-like α-cordierite polycrystals with submicron size could be obtained with the addition of 3 wt% H3BO3 at a calcining temperature of 1180 °C. This study broadens the range of complex oxides that can be obtained by the flux method and provides some references for the preparation of cordierite powder with good sinterability.