基于伴生稀土高岭土制备致密堇青石陶瓷的研究

Preparation of dense cordierite ceramics based on associated rare earth kaolinite

堇青石具有优良的力学性能,主要用于耐火材料等领域。本研究以天然高岭土矿物粉末为原料,通过成分调整并采用固相烧结法制备了高性能的堇青石陶瓷,利用气孔率、XRD、SEM、维氏硬度、抗弯强度等分析测试方法对堇青石结构和性能进行了表征。研究表明:堇青石陶瓷配比为伴生稀土高岭土80.2wt.%、氧化铝7.6wt.%和氧化镁12.2wt.%,当烧结温度由1100℃提升至1250℃,且原料粒度由100目降至300目,样品中堇青石相含量增加到96.6%,体积密度达到2.51 g/cm^(3)、致密度高达99.8%,维氏硬度上升至11.56 GPa,抗弯强度达到127 MPa,经3次热震循环后,材料的抗弯强度达到150 MPa。综合堇青石材料对硬度、抗弯强度与抗热震性能的要求,其最佳烧结温度为1200℃,且原料粒度越小,堇青石结构与性能越好。

Cordierite presents a range of excellent mechanical properties,mainly used in refractories and the related fields.In this study,cordierite ceramics with high performance were prepared by solid phase sintering with natural kaolin mineral powder as the raw material.The structure and properties of cordierite were characterized by porosity,XRD,SEM,Vickers hardness,and bending strength.The study showed that the ratio of cordierite ceramics is 80.2wt.%associated rare earth kaolin,7.6wt.%alumina,and 12.2wt.%magnesium oxide.When the sintering temperature increases from 1100℃to 1250℃and the particle size of raw materials decreases from 100 mesh to 300 mesh,the content of cordierite phase in the sample increases up to 96.6%,the volume density 2.51 g/cm^(3),the induced density 99.8%,the vickers hardness 11.56 GPa,and the bending strength 127 MPa.After three thermal shock cycles,the bending strength of the material reached 150 MPa.Considering the requirements of hardness,bending strength,and thermal shock resistance of cordierite material,the best sintering temperature is 1200℃.The smaller particle size of the raw material tends to bring about better structure and performance of cordierite.