本研究之目的為利用Boehmite包覆θ-Al2O3粒子，造成均一粒徑之θ-Al2O3粒子。此均一粒徑之θ-粒子可同時達到相轉換臨界晶徑dcθ，使相轉換反應時間集中，有助於生成大量30-50 nm α-粒子。
　　本研究利用混合不同比例之Boehmite (50、56、60 wt %) 與θ-Al2O3，經由球磨分散之混合系統漿料，調整pH值量測其粒徑分佈，以觀察其混合系統中Boehmite與θ-Al2O3粒子之關係。將此混合系統粉末以DTA觀察其熱行為，並以10℃/min 升溫至1100-1200℃ 間淬冷以保留樣品特性，此不同溫度淬冷之樣品觀察其α-生成量與比表面積之關係。
　　研究結果顯示：Boehmite之添加量有一最適值56 wt %，且在pH~4方可形成適當大小之Boehmite包覆θ-Al2O3粒子 (~30 nm)，此30 nm 的粒子由於其接近相變臨界晶徑dcθ，於相轉換反應發生時可同時相變，有利於生成大量30-50 nm 之α-粒子。過多或過少之Boehmite會導致此包覆粒子變大 (~50 nm)，導致反應時間延長，Tp溫度較高。

　　The purpose of this study was to obtain uniform q-Al2O3 particles by preparing q-Al2O3 coated with boehmite. The uniform q-Al2O3 particles were helpful to prepare a large number of a-Al2O3 crystallites with size ranging from 30 to 50 nm because they can grow to critical crystallite size and then transformed simultaneously.
　　In this present work, the relationships between boehmite and q-Al2O3 particles in the slurries that consist of q-Al2O3 powders with different amount of boehmite addition (50, 56, 60 wt %) were investigated. The mixed slurries were dispersed by ball milling. In addition, the pH values were adjusted and the particle size distribution were measured. The thermal behavior of the samples, which were form the mixed slurries, was examined by differential thermal analysis (DTA). The samples were thermally treated to 1100-1200℃ with a heating rate of 10℃/min and then quenched to room temperature. The relationships of a-formation and BET surface areas of these quenched samples were investigated.
　　It was found that there was a moderate boehmite addition (56 wt %) and the moderate size of q-Al2O3 particles coated with boehmite (about 30 nm) was at pH~4. Because q-Al2O3 powders with specific particle size (~30 nm) were close to the critical size dcq and then transformed to a-phase simultaneously, it’s helpful to form a large number of a-Al2O3 crystallites with size ranging from 30 to 50 nm. Excess or insufficient amount of boehmite caused the coated particles coarser and leaded to a longer reaction time or a higher transformation temperature (Tp).

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