가수분해반응으로 합성한 이트리아 안정화 지르코니아 분말의 물성

Abstract

Nano-sized yttria-stabilized tetragonal zirconia powder was synthesized by the hydrolysis reaction of mixed solution with zirconium oxychloride and yttrium nitrate. After the calcination and milling of precipitated zirconium hydroxide, powder characteristics, forming-ability and sintered properties were characterized as raw materials for a dental implant. Synthetic nano-sized zirconia particles had a primary particle size of 25〜30 nm and monolithic tetragonal phase. Primary agglomerates were only found in the powder with the size of 191 nm, but, not secondary agglomerate. Dense compacts were fabricated by the sintering at 1500 °C for 2 hours after the pressing using a synthetic powder without granulation. Low sintered densities of 5.7〜5.9 g/cm3 (relative density; 93.5〜96.5%) were found at heat-treatment of 1450〜1500 °C for 2 hours. Through the granulation by spray drying, highly performant zirconia powder was obtained. Spherical granules with the size of 44 μm were formed by spray drying at 200 °C. Green compact after pressing showed homogeneous microstructure on fracture surface , and it induced highly sintered zirconia specimens with an apparent density of 6.04 g/cm3 (relative density; 99.0%) and a grain size of 250〜300 nm at 1500 °C for 2 hours.