Development of Porous Ceramics with High-strength and Low-thermal-conductivity

摘要

Porous ceramics are utilized for various purposes such as thermal insulator, filter, catalyst carrier, etc. In gelation freezing method applied to porous ceramics fabrication, slurry in which ceramic powder is dispersed in water is gelled, frozen and dried. Since pores are formed by the removal of ice crystals formed during freezing process by drying, porous ceramic body can be availed without any special pore forming agents '. Although pore conditions can be controlled within a certain limit by regulating freezing direction or temperature, there has been a problem of large-sized defects appearing in ceramic body derived from coarse ice crystals which form occasionally in the freezing process. Porous ceramic body is fabricated with gelation freezing method which utilizes bubbles for suppressing the formation of coarse ice crystals. The effect of bubble addition is evaluated along with the influence of the amount of bubbles added to mechanical strength of fabricated porous body.