The invention relates to the field of
porous ceramics, in particular to a method for preparing a porous
ceramic by using a
tertiary butanol-based freezing sublimation method. The method disclosed by the invention basically has no restriction to an
oxide material system and is generally suitable for
engineering ceramics. The method comprises the following steps of: with
oxide ceramic powder as a
raw material,
tertiary butanol as a
solvent,
citric acid as a dispersing agent and
polyvinyl butyral as a binding agent, carrying out ball
grinding on the
raw material for 5-50h, pouring the uniformly-dispersed
raw material into a
polyethylene mold of which the bottom temperature is above 0 DEG C and the top temperature is
room temperature, and cooling for 5min-2h; and demolding, then sublimating for 24-27h by using a water
circulating pump under the condition of suction filtering, and heating to 1200-1600 DEG C in an air furnace and preserving the temperature for 5min-2h. According to the method disclosed by the invention,
slurry of an organic
system is prepared under the
room temperature; and the obtained porous
ceramic is distributed with directional holes, wherein the directional holes are polygonal holes and have the size distribution of below 100 microns and the longitudinal lengths of reaching
millimeter-scale. According to the method disclosed by the invention, the
porosity can be controlled by adjusting the
solid content, and the porous ceramic material with ultrahigh
porosity (more than 80 percent) can be prepared.