溶胶和微粉添加量对原位莫来石结合SiC陶瓷膜支撑体性能的影响  

Effect of sol and fine powder addition on properties of in situ mullite-bonded SiC ceramic membrane supports

作　　者：刘家栋 彭志坚[1] 刘开琪[2,3] 刘庆祝 陈运法 Liu Jiadong;Peng Zhijian;Liu Kaiqi;Liu Qingzhu;Chen Yunfa

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083 [2]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [3]中国科学院大学材料与光电研究中心,北京100049

出　　处：《耐火材料》2019年第5期348-353,共6页Refractories

基　　金：国家重点研发计划(2016YFB0601100);多相复杂系统国家重点实验室(MPCS-2017-A-06)资助项目

摘　　要：以d 50=247.0μm的SiC颗粒为主原料,分别加入12.5%、17.5%、22.5%(w)的混合溶胶(由正硅酸乙酯和铝溶胶按1:6质量比配成),或分别加入5%、10%、15%(w)的混合微粉(由d 50=20.9μm的SiC微粉和α-Al 2O 3微粉按质量比1∶2.5配成)作为原位莫来石结合的添加剂,并外加12.5%(w)的d 50=28.1μm的木炭粉为造孔剂,采用模压成型,在1400℃烧结3 h制备多孔SiC陶瓷膜支撑体。研究了两种添加剂对多孔陶瓷膜支撑体显气孔率、抗弯强度、孔径大小分布和透气性能的影响,并分析了试样的物相组成和断口形貌。结果表明:试样在烧结后均形成了莫来石结合相;随着溶胶添加量的增加,试样抗弯强度呈增长趋势,孔隙率逐渐减小;随着微粉添加量的增加,试样的孔隙率逐渐减小,抗弯强度呈先增大后减小的变化趋势。添加溶胶制备的莫来石结合多孔SiC支撑体具有更好的贯通气孔结构和力学性能,其中,添加17.5%(w)溶胶的试样具有良好的力学性能和透气性能,其抗弯强度达到28.2 MPa,孔隙率为37.2%,平均孔径为89.6μm,阻力降为41.0 Pa。Porous SiC ceramic membrane supports were prepared by moulding and sintering at 1 400℃for 3 h using SiC particles(d 50=247.0μm)as the main raw material,adding mixed sol(12.5%,17.5%and 22.5%,by mass,the same hereinafter;mass ratio of tetraethyl orthosilicate to alumina sol 1∶6),or adding mixed fine powder(5%,10%and 15%;mass ratio of SiC particles with d 50=20.9μm toα-Al 2O 3 1∶2.5)as the additive,extra-adding 12.5%charcoal powder(d 50=28.1μm)as the pore-forming agent.The effects of the two kinds of additives on the apparent porosity,the modulus of rupture,the pore size distribution and the air permeability of the porous ceramic membrane supports were studied,and the phase composition and the fracture morphology of the specimens were analyzed.The results show that all specimens have mullite-bonded phase after sintering;the modulus of rupture increases and the porosity decreases with the increase of the sol addition;however,the porosity decreases gradually and the modulus of rupture increases firstly and then decreases with the increasing powder addition.The mullite bonded porous SiC supports prepared using sol have better permeable pore structure and mechanical properties.The specimen added with 17.5%sol has good mechanical properties and air permeability:modulus of rupture of 28.2 MPa,porosity of 37.2%,average pore size of 89.6μm,and pressure drop of 41.0 Pa.

关 键 词：碳化硅 瓷膜膜支撑体 原位莫来石结合 正硅酸乙酯 铝溶胶 阻力降 

分 类 号：TQ175[化学工程—硅酸盐工业]