The invention relates to a preparation method of porous Al2O3
ceramic. The preparation method comprises the steps: adopting sintered-plate shaped alundum
powder as
raw material, adopting water glass solution as a binding agent, mixing the sintered-plate shaped alundum
powder and the water glass solution into suspending liquid, fully stirring, injecting the obtained suspending liquid into a mold, freezing the suspending liquid in a vacuum freeze dryer, carrying out continuous
drying thoroughly under
vacuum state on the frozen suspending liquid, then demolding the sample, placing the demolded sample into a high-temperature box-type electric furnace, rising the temperature to 1500-1600 DEG C, keeping the temperature for 2 hours, and cooling naturally along the furnace to obtain the porous Al2O3
ceramic. As a vacuum
freeze drying technique is adopted, the invention does not add any organic or
inorganic chemical harmful substances, does not need special templates, and adopts ice as a hole-making template; and after the ice
crystal is sublimated and removed, the
ceramic particles obtain a
porous microstructure of negative duplicates for growth of the ice
crystal. The preparation method better inherits the ice
crystal appearance, also does not need the processes of removing the templates, such as calcining, chemical
etching and the like, not only has simple technique, but also has unique hole structure, and is easy to obtain a special hole structure.