Porous ceramics with fine uni-directionally-aligned continuous pores

Porous ceramics including alumina, silicon nitride and silicon carbide with fine uni-directionally-aligned continuous pores (UDAP) were developed by slurry coating of fugitive fiber (SCF) in this study. Cotton threads were selected as the fugitive fibers in the present work. They were coated with ceramic slurry by pulling them through slurry and specimen was produced by spooling the coated threads. The diameter of the pores and the open porosity can be adjusted by the diameter of cotton thread and the ceramic concentration of the slurry, respectively. An obtained porous alumina ceramics produced by SCF with a pore diameter of 165 mum, open porosity of 35% showed a bending strength of 160 MPa. For silicon nitride and silicon carbide porous ceramics, a two-step burnout process of cotton thread should be used for keeping the product from collapse during the sintering process.