烧成温度对稀土尾砂堇青石多孔陶瓷显微结构与性能的影响

Preparation of Porous Cordierite Ceramic Materials from Rare Earth Tailings

以赣南稀土尾砂为主要原料，通过高温固相反应烧结制备了低膨胀堇青石陶瓷材料，研究了烧成温度对其物相组成、显微结构、烧成收缩、气孔率和体积密度、热膨胀系数和抗弯强度等的影响。结果表明，在1240-1340℃保温3h烧成可制备出多孔结构的堇青石陶瓷材料，其中1270℃烧成制备的试样表现出最大气孔尺寸和气孔率及最小的体积密度。烧成温度提高有利于促进低膨胀的堇青石晶相合成，降低试样的热膨胀系数。烧成温度从1200℃提高到1240℃以上时，试样的抗弯强度明显降低。在1240-1340℃保温3 h烧成制备的多孔堇青石陶瓷材料的热膨胀系数和抗弯强度分别为3.1~3.6×10-6/℃和22.6-37.5 MPa。

Low expansion cordierite ceramic materials were prepared by high temperature reaction sintering, using rare earth tailings from South Jiangxi as the main raw materials. The inlfuences of sintering temperature on the phase composition, microstructure, linear shrinkage, porosity and bulk density, thermal expansion coefifcient （TEC） and lfexural strength of prepared cordierite ceramics were investigated. Results show that porous cordierite ceramic materials can be obtained sintered at 1240-1340℃for 3 h, and the sample sintered at 1270℃ has the maximum pore size and porosity and minimum bulk density. The increase in sintering temperature contributes to the synthesis of cordierite phase and thus lower TECs. The lfexural strength of prepared samples decrease signiifcantly with the sintering temperature increased from 1200℃ to more than 1240℃. The cordierite ceramic sintered at 1240-1340℃ for 3 h exhibit the TEC of 3.1-3.6×10-6/℃ and the lfexural strength of 22.6-37.5 MPa.