鈦酸鋇具有良好的介電材性質，因此在工業上廣泛應用於被動元件、熱敏電阻器、溫度感測器等多種高容電子產品。為了使製成的電子元件能符合工業規格需求 (Y5V、X8R、X9R 等)，通常在鈦酸鋇中加入添加物，進行離子置換以改變介電常數變化率隨溫度改變的特性。本研究以鈦酸鋇為基礎，選擇氧化釔 (1.0 mol%, 3.0 mol%) 及氧化鎂 (0.5 mol%, 1.0 mol%) 作為添加，瞭解釔離子進入 Ba位置及鎂離子進入 Ti 位置後對於微結構、晶體結構與介電性質之影響，並以在較低溫獲得高緻密度且小晶粒之殼-核結構之陶瓷體為目的。
實驗結果顯示，單一添加氧化釔能抑制晶粒成長，少量添加會促進鈦酸鋇燒結收縮，當添加量提高為 3.0 mol% 會轉變為抑制燒結。單一添加氧化鎂則能促進鈦酸鋇燒結收縮和抑制晶粒成長，並獲得較平坦的溫度-電容曲線 (TCC)。透過晶格計算得知，鎂離子進入 Ti 位置後，單位晶格的 a 軸伸長、c 軸縮短，正方性下降。當氧化釔添加量從 1.0 mol% 增加為 3.0 mol% 時，部分的釔離子會取代 Ti 位置，或在晶界處析出形成 Y2Ti2O7 二次相，亦造成正方性下降。
在共添加系統中，0.5Mg1Y、0.5Mg3Y 和 1Mg1Y 樣品在 1150°C 持溫 3 小時，獲得相對密度 90 % 以上的燒結體，0.5Mg3Y 樣品的晶粒大小約在 0.7 μm - 1.0 μm 之間，由 TEM 圖中可證明，其燒結體具有殼-核結構，其中 0.5Mg3Y 陶瓷體之電容-溫度曲線符合工業之規格 (X8R)。

Due to the great performance of dielectric properties, barium titanate was used in great number of high-K capacitor products, such as passive devices, thermistors, and temperature sensors. To make electric device achieve the industrial specifications (Y5V, X8R, X9R, etc), we usually added additives into the barium titanate proceeding ion exchange to adjust the dielectric constant with temperature. The core-shell structure was obtained by Y2O3 and MgO doped into BaTiO3-based material. In this study, we investigated the microstructure, crystal structure and dielectric properties.
Doping Y2O3 can suppress grain growth of BaTiO3 bulk. The addition of 1.0 mol% Y2O3 into BaTiO3 can promote its sintering shrinkage. However, the sintering shrinkage was suppressed when amount of Y2O3 is 3.0 mol%. Doping MgO can enhance sintering shrinkage and suppress grain growth of BaTiO3 bulk, and acquire a flatter TCC curve. The addition of 3.0 mol% Y2O3 can exceed the solubility of A-sites. The tetragonality decreased as the amount of Y2O3 and MgO increased.
The bulk density of 0.5Mg1Y, 0.5Mg3Y, and 1Mg1Y specimens sintered at 1150°C/3h was more than 90%, and the grain size of 0.5Mg3Y was between 0.7 μm - 1.0 μm. The TCC curve of 0.5Mg3Y bulk when sintered at 1150°C/3h could achieve X8R specification.

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