Preparation of large effective specific surface area reticulate porous ceramics by polymeric foam replication process using recoating technique

Abstract

Large effective specific surface area reticulate porous ceramics (RPC) were fabricated by a polymeric foam replication process using of two-step route (presintering-recoating). The coating slurries used clay as the major material and silica sol etc. as a binder, while the recoating slurries consisted of lower concentration coating slurries and pore-forming materials such as starch or graphite. The solids-content of the recoating slurries which could effect on the porosity and the coating amount of sintered bodies was optimized in our work. Specific surface area and the pore size distribution of the RPC were measured by intrusive mercury curve. Morphological characteristics of the RPC were investigated by SEM. Comparing with the uncoated RPC, the recoated RPC had still highly porosity (80%) and a higher compressive strength. A lot of pores and apertures left on the surface of the sintered RPC’s after those starch/graphite pore-forming materials were burned out, thus lead to a remarkable increase in the specific surface area. The maximal effective specific surface area (ignore the pores size below 10 microns) of the recoated RPC is 0.52 m2/g, as over ten times as the uncoated RPC.