| 摘要 |
PROBLEM TO BE SOLVED: To process the whole of a ceramic so as to be porous by imparting faint vibration to the ceramic having the interior formed into the porous one and after sintering thereof. SOLUTION: A powder with <=100 μm size is obtained preferably by using tribasic calcium phosphate, and 3-15 wt.% aqueous solution of a polyvinyl alcohol as a binder in an amount of 2-4 times as much as the weight of the powder is added to the powder. The resultant mixture is stirred and mixed at >=2,000 rpm to form bubbles in the slurry. The obtained slurry with the bubbles is inserted into a mold and freeze-dried, and the freeze-dried product is sintered at 1,000-1,400 deg.C to provide a ceramic with free shape. The obtained ceramic is immersed in an aqueous solution, and an ultrasonic wave of 20-50 kHz, e.g. having 0.1-5 W/cm2 output is applied for 30-250 sec. The most outer surface of the sintered body is peeled off by the application of the ultrasonic wave, and the pores in the interior appear on the surface. The pores and bubbles can be impregnated with a chemical or the like and the porous ceramic can be a sustained release carrier for the chemical. The porous ceramic can be also used as an aggregate. |
