本研究探討θ-Al2O3/boehmite混合水系漿料系統，因其pH值不同可能形成的θ-Al2O3/boehmite凝聚狀態差異，可致以其乾膠熱處理所得之α-Al2O3粒體特性也不同。使用之θ-Al2O3/boehmite原料重量比固定為30對82.35（Al2O3/Al2O3=30/70）。混合後漿料固粒含量為20 wt％。兩成分的混合採取兩種方式：系統A是先將二者分散良好（pH=4）再混合，再調整為不同的pH漿料系統。系統B則將兩成分各調整至預定相同pH後再混合。混好樣品均以DTA觀察系統粉末之熱行為，瞭解其α-Al2O3出現溫度。利用XRD、BET、TEM等儀器進行所得煆燒樣品之特性分析。
研究結果顯示：混合系統（A、B）均會隨pH升高而有較大凝聚體產生且θ-到α-Al2O3的相轉換溫度有隨pH值升高而延後發生的現象。兩種方式均有可能形成類似core(θ-Al2O3)–shell(boehmite)之結構。二者因pH值不同產生的最大差異在於A系統可造成相近的θ-Al2O3/boehmite分佈關係，凝聚體粒子間距離雖改變，但core-shell的質量不變，因此對於所得到的α-Al2O3粒子也因此差異不大。B系統則因二成分已先作凝聚狀態的改變，當進入混合形成core-shell時，θ-Al2O3凝聚體大者會導致core-shell顆數的減少，每顆質量變大。結果可知B系統透過pH調整，可對所得之α-Al2O3粉末晶徑進行調整。

In this study, the mixed slurries of θ-Al2O3 and boehmite may be different in the agglomeration by pH value adjusting. The characterizations of α-Al2O3 were further different by calcining the mixed slurries of θ-Al2O3 and boehmite. The alumina ratio of θ-Al2O3 to boehmite was 30 to70.The solid contain of θ-Al2O3 and boehmite were 20 wt%. There were two ways to mix. First, pH value of A system adjusted after two dispersal materials mixing. Second, two materials mixed after two materials adjusting pH value variously. The thermal behavior of the samples, which were from the mixed slurries, was examined by differential thermal analysis (DTA). The characterizations of α-Al2O3, which were form the mixed slurries, were examined by XRD、BET、TEM analysis.
The results showed that: A、B systems both arise larger agglomerates and lead to a higher transformation temperature when pH value is higher. This two ways may both bulid homo-core(θ-Al2O3)-shell(boehmite) structure. Although the agglomeration has changed, the mass of core-shell was in the same which caused the size of α-Al2O3 constant in A system. Contrarily, because the two components had changed in the agglomeration, the larger agglomerate of θ-Al2O3 caused the number of core-shell lower and the mass of core-shell biger. Finally, the size of α-Al2O3 could be altered via pH adjusting in B system.

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