中文摘要 本研究的目的是在低溫下製備出具有均一粒徑且可分散在溶劑中的氧化鋯奈米結晶。過程中先探討影響氫氧化鋯水解程度的因素，然後找到適當條件製備出氧化鋯奈米結晶。最後將之表面改質使可分散於中性溶劑。 本研究以氯氧鋯為原料，先配製含鋯之酸液。再以氨水或者氫氧化鈉將之中和以水解沉降製成氫氧化鋯。最後再以水熱反應將氫氧化鋯製成氧化鋯結晶。其中探討離子濃度、pH值、水熱溫度等變因對產生氧化鋯之粒徑及結晶性的影響。我們發現在鹼性下合成出的氫氧化鋯可以製成較均勻之半透明氧化鋯粒子溶膠。此一溶膠經過凝絮過濾清洗等步驟得到非晶形之氧化鋯凝膠。再將凝膠分散於氫氧化鈉溶液中，於110℃下水熱15小時後，可得到30nm左右之t-ZrO2。經由表面改質後製出可再分散於中性溶液之奈米結晶。 Abstract This work describes the low-temperature synthesis of zirconia nanocrystals. The synthesized nanocrystals are aggregate-free and can be redispersed in neutral solutions.The zirconia nanocrsytals are synthesized from zirconium oxychloride via intermediate formation of zirconium hydroxide, precipitated by the addition of NaOH or NH4OH. The transformation of zirconium hydroxide into the nanocrystals of zirconia was effected by a hydrothermal treatment.The hydrolysis of zirconium oxychloride was found to be dependent on pH and was highest at pH 10, amongst the pH range studied. The hydrolyzed product of zirconium oxychloride was maintained at pH 11.5 and was hydrothermally treated at 1100C, for 15 h, which then produced nanocrystals.The nanocrystals obtained were 10 nm in size(TEM and XRD analysis). Te nanocrystals could be redispersed in water upon their surface modification; this suspension gave particle size of 30 nm on DLS analysis. The nanocrystals showed tetragonal geometry (XRD and EDS) and the crystallinity (DSC) was near to 100%.
