近年來鈦酸鋇粉體之合成隨著基層陶瓷電容器 (MLCC) 之蓬勃發展變得愈來愈重要，合成出小粒徑之鈦酸鋇粉體，更是許多研究的目標；以傳統固相反應法合成的粉體，在純度、均勻性及粒徑分佈上皆不如化學法，但在成本考量上，固相反應法仍具有其優勢。因此，本研究乃希望透過改善固相反應法原料混合不均的缺點，以化學法將碳酸鋇披覆在二氧化鈦表面，亦期望因兩者擴散距離的縮短，可於較低的煅燒溫度下，合成出鈦酸鋇粉體。本研究之結果顯示，過量尿素之添加 ([urea]/[cation] ratio = 30) 有助於提高碳酸鋇之生成率；由TEM、FTIR及TEM電子繞射圖譜之結果可知，尿素及硝酸鋇的反應物為碳酸鋇，此外，反應生成之碳酸鋇粒徑極小 (約30 nm) ，並可批覆於二氧化鈦表面。將反應後之粉體於不同煅燒溫度下進行熱處理，最終可在1000oC持溫1小時之煅燒條件下，獲得單一相之鈦酸鋇粉體。藉由XRD及Raman光譜分析之結果，合成出之鈦酸鋇為正方晶相 (tetragonal) 之結晶結構，tetragonality為1.0053。

Barium titanate finds extensive application in the electronic industry, particularly in multilayer ceramic capacitors (MLCCs). The fabrication of very thin (<1 um) dielectric layers applied for the next-generation MLCC will require BaTiO3 with sub-micron or even nano-scale particle. The powder synthesized by conventional solid-state reaction normally has lower barium to titanium homogeneity and usually needs high calcination temperature and strong milling procedure afterwards. That makes the solid-state powder has relative lower purity and wider particle size distribution than that of the chemical-route powders. To improve the homogeneity of barium and titanium in solid-state reaction, urea and Ba(NO3)2 are used as the starting materials, they are expected to react and form the Ba-compound and precipitate onto the TiO2 surface, forming the so called core-shell structure. That will shorten the diffusion distance during calcination and make the formation of BaTiO3 at relatively lower temperature become possible. The experimental results show that the nano scale Ba-compound (~30 nm) can be obtained and effectively coated on TiO2 surface. The TEM, FTIR and TEM diffraction pattern reveal that this Ba-compound is BaCO3. The yield rate of BaCO3 can be up to 97% when the reaction is performed at [urea]/[cation] ratio of 30, under the condition of 90oC/36h. After 1000oC/1h calcination, the single-phase BaTiO3 can be obtained. The Raman spectra and XRD pattern demonstrate that the crystal structure of the obtained BaTiO3 powder is tetragonal phase and the tetragonality is 1.0053.

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