TiO_2对堇青石多孔陶瓷微观结构和性能的影响

Influence of Titanium Dioxide on the Microstructure and Properties of Porous Cordierite Ceramics

以叔丁醇为成形介质和造孔剂,二氧化钛为烧结助剂,采用凝胶注模成形和无压烧结工艺制备堇青石多孔陶瓷。研究了添加5%(体积分数,下同)二氧化钛对堇青石多孔陶瓷的气孔率、微观结构、力学性能和气孔结构的影响,并对样品的断口形貌进行观察。结果表明,在1175℃烧结温度条件下,与不添加二氧化钛相比,当二氧化钛含量为5%时,所得堇青石多孔陶瓷的气孔率和开口气孔率分别由76.9%和96.4%下降为72.4%和95.1%,线性收缩率从20.7%提高到22.1%,而抗压强度则由3.23MPa提高到5.83MPa,气孔尺寸均呈单峰分布,中位孔径由2.29μm下降到1.62μm。二氧化钛的加入提高了堇青石粉末的低温烧结性能,在未明显降低堇青石多孔陶瓷气孔率以及未改变其气孔结构、孔径尺寸分布的前提下,材料的力学性能得到了显著改善。

Porous cordierite ceramics was successfully fabricated by gelcasting and pressureless sintering process with tert-butyl alcohol as the pore-former and titanium dioxide as the sintering assistant. The influences of 5% titanium dioxide on porosity, microstructure, mechanical properties and pore structure of porous cordierite ceramics were studied, and the fracture morphology obtained after compression experiment was also observed. Compared to the cordierite ceramics without the addition of TiO2, with the addition of 5% TiO2 and at 1175℃ of sintering temperature, the porosity and open porosity of the sintered cordierite ceramics decreased from 76.9% and 96.4% to 72.4% and 95.1%, respectively. The line shrinkage ratio increased from 21.3% to 23.5%, and the compression strength increased from 3.23 MPa to 5.83 MPa. The pore size presented single peak distribution, and the median pore diameter decreased from 2.29 μm to 1.62 μm. The addition of titanium dioxide increased the sinterability of the cordierite ceramics. The mechanical properties of the materials were greatly improved while the porosity, pore structure and pore size distribution of the porous cordierite ceramics were not obviously changed.