研究了陶瓷纤维过渡层浆料的不同工艺配方对复合碳化硅过滤膜材料结构的影响,陶瓷粘结剂量对过滤膜的孔隙率、孔径大小和孔径分布的影响,以及陶瓷粘结剂量为15wt%时,造孔剂量对过滤膜孔隙率的影响。采用流延成型法在多孔碳化硅陶瓷块体上流延制备复合碳化硅陶瓷过滤膜,并用XRD对过滤膜进行物相分析,扫描电镜观察过滤膜的形貌,表面过滤膜的孔隙率和孔径分布则用排水法和泡点法分别测试。结果表明,1300oC烧结3h后的碳化硅过滤膜在2θ=22o时,有SiO2衍射峰生成。当陶瓷纤维过渡层浆料各成分的质量比为:硅酸铝纤维、莫来石纤维、羧甲基纤维素钠(CMC)、和蒸馏水=1:X(X=0,0.5,1.0,1.5):1.5:65,当0≤X≤1.0时,随着莫来石纤维含量的增加,复合碳化硅陶瓷过滤膜愈均匀平整,纤维过渡层起到的承接阻碍作用,使过滤膜层不易进入支撑体的空隙;当X>1.0(X=1.5)时,莫来石纤维加入过量,使纤维过渡层过厚,过滤膜和支撑体附着不紧密,容易脱落;当X=1.0,莫来石纤维加入量最合适,复合碳化硅陶瓷过滤膜结构最均匀平整。当粘结剂量5wt%增加到25wt%时,过滤膜气孔率从46%下降到29%,平均孔径从11.916μm减小至4.017μm;当粘结剂量为15wt%,造孔剂量从5wt%增加到25wt%时,过滤膜气孔率从41%上升到60%。
Various compositions of ceramic fiber slurry were prepared to discuss the influence of ceramic fiber layer on structure of SiC filtration membrane ,effect of bonding agents on porosity and pore size distribution of filtration membrane, when bonding agentss at 15wt%,,effect of pore-forming agent on porosity of filtration membrane. Tape casting method was used to prepare the filtration membrane covering on the SiC green body. And XRD and SEM were performed to examine the phase constitution and morphology. The porosity and pore size distribution of filtration membrane were tested by Archimedes method and bubble point method respectively. The results show that, there is a SiO2 diffraction peak with the 2θ =22°in the filtration membrane sample sintered at 1300℃ for 3h. When the composition of ceramic fiber slurry in mass ratio of aluminum silicate fibers: mullite fibers: CMC: water is 1: X(X=0,0.5,1.0,1.5): 1.5: 65, and 0≤X≤1.0, the SiC ceramic filtration membrane becomes more uniform and complete with the increasing content of mullite fibers. Meanwhile, ceramic fiber layer can prevent the filtration membrane falling into the gaps of SiC support body. While X﹥1.0(X=1.5), excess mullite fibers lead a bad adhesive quality of SiC support body and filtration membrane. X=1.0 is an appropriate content of mullite fibers, and the whole complex SiC ceramic filtration system has a perfect structure. However, if there is not any ceramic fiber layer, the filtration membrane drops into the gaps of SiC support body easily which has an impact on the structures and properties of complex SiC ceramic filtration membrane material.When the content of bonding agents increased from 5wt% to 25%, however, the porosity dropped from 46% to 29% and average pore size decreased from 11.916μm to 4.017μm. The porosity was changed from 41% to 60% with the amount of bonding agents was fixed at 15% but the content of pore-forming agents became from 5wt% to 25%.