关键词: 碳化硅, 多孔陶瓷, 聚氨酯发泡, 网状孔壁, 过滤效率, 固含量

Abstract: In order to improve the filtration performance,silicon carbide porous ceramics with network cell wall were fabricated via the polyurethane foaming method using silicon carbide powder,alumina powder,polyether polyol,polymethylene polyphenyl polyisocyanate,dibutyltin dilaurate,triethylenediamine and silicone oil (foam stabilizer) as raw materials.The effects of the solid loadings of the slurry (45%,50%,55% and 60%,by mass) on the microstructure,physical properties and their filtration properties towards particulate matters were studied.The result shows that:(1)with the increasing solid loading,the bulk density and cold compressive strength gradually increase,and the apparent porosity decreases;(2)the micropores generated during the polyurethane foaming process are distributed on the ceramic pore wall to form a network cell wall structure,which increases the collision probability between particles and the wall pores and improves the filtration efficiency;meanwhile,the network cell wall structure also improves the pore interconnectivity and reduces the press drop;(3)when the solid loading is 55%,the silicon carbide based porous ceramics have the bulk density of 0.57 g·cm^-3,apparent porosity of 79.2%,cold compressive strength of 3.7 MPa,and the filtering efficiency of the particulate matter of 91.2%,achieving good regeneration performance.

Key words: silicon carbide, porous ceramics, polyurethane foaming, network cell wall, filtering efficiency, solid loading