Abstract
A new-type porous strucutre, named ‘KAMINARI-OKOSI’ struture, was succesfully prepaerd utilizing both aquaous gel-casting slurry and resin filter and measured their pore size distribution, air permiability, bending strength and electrical conductivity. The slurry compositon contained pore former such as carbon, nickel caobonate to induce relatively small pore in calcinated body. On the other hand, a resin filter immersed into the slurry also acted as an another pore former and left relativery large pore after calcination. By the contribution of these two different vanishing materials, obtained porous body was consist of large porous sphericals bonding together and realized a bi-modal open-pore size distribution showing relatively large size pore (around 10 × 10-6m) and ordinary size pore (around 10-6m). After reduction at 1073K in H2, Ni/YSZ cermets having the ′KAMINARI-OKOSI′-type structure were allowed to high air permiability, and which made possible to fire at high temperature and to obtain high bending strength. This porous body having ′KAMINARI-OKOSI′-type structure was combined with a porous body having conventional porous structure, named ′KARUME-YAKI′-type one, to make thin YSZ electrolyte layer on the surface of porous body with ease and form a number of 3-phase interface site as active catalytic points. Splendid characteristics of the porous body combined ′KAMINARI-OKOSI′-type and ′KARUME-YAKI′-type structure in ratio of 6:4 by thicness were obtained as follows: air permiability of around 10-7m4·kg-1·Sec-1 at room temperature, 3-point bending strength of 34 MPa at room temperature and electrical conductivity of around 104S. m-1 at 1073K.
