The invention belongs to the field of ceramics, and particularly relates to a preparation method of a high-quality
ceramic flat plate, which comprises the following steps: adding POSS (Polyhedral Oligomeric
Silsesquioxane) into
hydrochloric acid, carrying out ultrasonic treatment for 20-30 minutes, taking out a precipitate, putting the precipitate into a
sodium hydroxide solution, carrying out
microwave treatment for 1-2 hours, taking out, washing and
drying to obtain hydroxylated POSS; the preparation method comprises the following steps: adding aluminum isopropoxide into
ethanol, uniformly stirring to form a dissolving solution, putting hydroxylated POSS into the dissolving solution, carrying out low-temperature
microwave treatment for 20-30 minutes, carrying out constant-
temperature treatment for 30-50 minutes to form a concentrated solution, taking out the concentrated solution, naturally airing the concentrated solution, and carrying out heating treatment to obtain aluminoxyl modified POSS; carrying out ball milling on nano aluminum
oxide, aluminoxyl modified POSS,
methyl cellulose and an
ethanol water solution, and carrying out constant-
temperature treatment for 20-30 minutes to obtain
slurry; carrying out vacuum stirring and defoaming on the
slurry, and then carrying out
tape casting and preliminary
sintering to obtain a
ceramic green body;
coating the surface of the
ceramic green body with
silicon-aluminum liquid,
coating the surface with
aluminum foil after
drying, carrying out
microwave treatment for 20-40 minutes, and cooling and standing to obtain a pretreated flat plate; and carrying out presintering treatment on the pretreated flat plate for 1-2 hours, and carrying out isostatic pressing treatment for 2-5 hours to obtain the high-quality ceramic flat plate.