臺灣博碩士論文加值系統

近年來鈦酸鋇粉體之研究隨著積層陶瓷電容器 ( Multilayer ceramic capacitor, MLCC) 之蓬勃發展變得愈來愈重要，欲使鈦酸鋇達到高電容且同時具備穩定的溫度-電容變化曲線，添加適當的元素或化合物作為添加劑的選擇及研究就變得重要。除了添加劑的選擇外，使用傳統固相反應法在純度、均勻性及粒徑分佈上皆不如化學沉澱法，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混合不均勻之缺點，利用尿素沉澱法作為製程方法，硝酸鎂 (0.5 mol%) 及硝酸釔 (2.0 mol%) 作為添加劑，選擇先披覆鎂再披覆釔並探討尿素沉澱法對於本系統之最佳實驗參數，並於得到高緻密陶瓷體後，對燒結行為、顯微結構及介電常數做探討。
本研究之結果顯示，以尿素沉澱法披覆鎂於鈦酸鋇上，需於90oC之環境下，尿素添加倍率一倍，持溫24小時後，經由煅燒900oC持溫3小時，形成鈦酸鋇鎂之固溶體。之後再以尿素沉澱法披覆釔於鈦酸鋇鎂固溶體上，需將尿素添加倍率增加為30倍，產率才可達相對理論產率的 90% 以上，並於1250oC、1300oC持溫3小時之燒結條件下，發現核殼結構的存在，使溫度-電容變化曲線 (TCC) 平坦化，並與固相反應法做比較，使用尿素沉澱法具有正面的幫助。

This study investigates the effects of doping barium titanate with magnesium and yttrium using a urea-precipitation method. In this approach, magnesium oxide and yttrium oxide are synthesized and coated on Barium titanate core powder using the urea-assist reaction of magnesium nitrate and yttrium nitrate. It turns out that the reaction yield can be high when the reaction is performed at 90°C for 24 hours. Barium titanate powder coated with yttrium needs more urea. The magnesium oxide can be seen after calcination at 900°C, and forms a coating layer of barium titanate. The core–shell structure can be obtained in Barium Titanate ceramics that are co-coated with magnesium oxide and yttrium oxide upon sintering at 1250°C and 1300°C for 3 h. The TCC curve can also be flattened. This precipitation method is more helpful than the solid reaction method.

摘要 I
致謝 VII
總目錄 VIII
表目錄 X
圖目錄 XI
第一章 緒論 1
1-1前言 1
1-2研究目的 1
第二章 理論基礎及前人研究 2
2-1 鈦酸鋇之晶體結構及其性質 2
2-2 鈦酸鋇之合成粉體方法:固相反應法、化學沉澱法 (尿素沉澱法) 8
2-2-1 固相反應法 8
2-2-2 化學沉澱法 (尿素沉澱法) 9
2-3 核殼結構 (core-shell structure) 對於介電性質之影響 11
2-4 Mg2+及Y3+的添加對於鈦酸鋇顯微結構及介電特性之影響 14
2-4-1 Mg2+的添加對於鈦酸鋇顯微結構及介電特性之影響 14
2-4-2 Y3+的添加對於鈦酸鋇顯微結構及介電特性之影響 22
第三章 實驗方法與實驗流程 29
3-1 起始原料 29
3-2 實驗方法及實驗流程 31
3-2-1 尿素沉澱法 33
3-2-2 粉末之熱差/熱重分析 33
3-2-3 陶瓷體製備及燒結收縮量測 34
3-3材料特性及性質分析 36
3-3-1 表面電位量測 36
3-3-2 陶瓷體之密度量測 36
3-3-3 X光粉末繞射分析 36
3-3-4 晶格常數分析 38
3-3-5 掃描式電子顯微鏡 38
3-3-6 穿透式電子顯微鏡 39
3-3-7陶瓷體樣品準備與介電常數量測 39
3-3-8 溫度-電容曲線量測 39
第四章 結果與討論 41
4-1 製程參數 41
4-2反應生成物之組成及狀態分析 47
4-2-1鈦酸鋇披覆之粉末熱差/熱重分析及相鑑定結果 49
4-2-2鈦酸鋇反應生成物之熱差/熱重分析及相鑑定結果 52
4-2-3鈦酸鋇粉末表面披覆之狀態 54
4-3 陶瓷體特性分析 59
4-3-1 陶瓷體之燒結收縮量測分析 59
4-3-2 陶瓷體之結晶相分析及晶格常數分析 59
4-3-3 陶瓷體之顯微結構分析 63
4-3-4 陶瓷體之介電常數及溫度-電容曲線 67
4-4 尿素沉澱法與固相反應法之比較 70
第五章 結論 77
參考文獻 78

1.K. Kishi, Y. Mizuno, and H. Chazono, “Base-Metal Electrode Multilayer Ceramic Capacitors: Past, Present and Future Perspectives, Jpn. J. Appl. Phys., 42, 1-15, (2003).
2.G. Arlt, D. Hennings, and G. With, “Dielectric Properties of Fine Grain Barium Titanate Ceramics, J. Appl. Phys., 58, [4], 1619-1625, 15 August, (1985).
3.A. J. Moulson and J. M. Herbert, Electroceramics: Materials, Properties, and Applications, Chapman and Hall, New York, (1990).
4.I. Sondi and E. Matijevic, “Homogeneous Precipitation by Enzyme-Catalyzed Reactions. 2. Strontium and Barium Carbonates, Chem. Mater., 15, 1322-1326, (2003).
5.F. Boschini, B. Robertz, A. Rulmont, and R. Cloots, “Preparation of Nanosized Barium Zirconate Powder by Thermal Decomposition of Urea in an Aqueous Solution Containing Barium and Zirconium, and by Calcination of the Precipitate, J. Eur. Ceram. Soc., 23, 3035-3042, (2003).
6.C. Beddie, C. E. Webster, and M. B. Hall, “Urea Decomposition Facilitated by a Urea Model Complex: a Theoretical Investigation, Roy. Soc. Chem., 3542-3551, (2005).
7.張哲源，以尿素-硝酸鋇沈澱之碳酸鋇披覆於二氧化鈦以合成鈦酸鋇之研究。國立成功大學資源工程研究所碩士論文(2006)
8.W. R. Buessem, L. E. Cross, and A. K. Goswami, “Phenomenological Theory of High Permittivity in Fine-Grained Barium Titanate. J. Am. Ceram. Soc., 49 [1] 33-36 (1966).
9.K. Kobayashi, J. Nishikawa, T. Suzuki, and Y. Mizuno, “Microstructure Study of BaTiO3–Ho2O3–MgO–SiO2-Based Ceramics Using Convergent Beam Electron Diffraction Analysis Jap. J. Appl. Phys., 48 [9] 09KC05-09KC05-4 (2009).
10.J. Nishikawa, T. Hagiwara, K. Kobayashi, Y. Mizuno, and H. Kishi, “Effects of Microstructure on the Curie Temperature in BaTiO3–Ho2O3–MgO–SiO2 System, Jap. J. Appl. Phys., 46 [10B] 6999-7004 (2007).
11.Q. Feng, and C. J. McConville, “Weak-Beam Dark-Field Microscopy of Complex Stress States in X7R-Type BaTiO3 Dielectric Core–Shell Structures, J. Am. Ceram. Soc., 87 [10] 1945-1951 (2004).
12.Arlt, D. Hennings, and G. de With, “Dielectric properties of fine‐grained barium titanate ceramics, J. Appl. Phys., 58 [4] 1619-1625 (1985).
13.M. H. Frey, and D. A. Payne, “Grain-size effect on structure and phase transformations for barium titanate, Ame. Phys. Soc., 54 [5] 3158-3168 (1996).
14.R. L. Coble, “Sintering Crystalline Solids : Ⅱ Experimental Test of Diffusion Models in Powder Compacts, J. Appl. Phys., 32, 793-799, 1961.
15.T.Nagai and K. Iijima, “Effect of MgO Doping on the Phase Transformations of BaTiO3, J. Am. Ceram. Soc., 83 [1], 107-12, 2000.
16.Jeong and Y. H. Han, “Effects of MgO-Doping on Electrical Properties and Microstructure of BaTiO3, Jpn. J. Appl. Phys., 43, 2004, 5373-5377.
17.D. E. Rase and R. Roy, “Phase Equilibria in the System BaO-TiO2, J. Am. Ceram. Soc., 38, [3], 102-113, (1955).
18.S. Lee, C. A. Randall, and Z. K. Liu, “Modified Phase Diagram for the Barium Oxide-Titanium Dioxide System for the Ferroelectric Barium Titanate, J. Am. Ceram. Soc., 90 2589-2594 (2007).
19.S. T. Bae, D. K. Yim, and K. S. Hong, “Role of Liquid Phase in Achieving a Fine Microstructure and Diffusive Phase Transition of MgO-Doped BaTiO3, J. Appl. Ceram. Technol., 679-686, 2009.
20.Preparation of MgO-coated BaTiO3 particles through a surface-induced precipitation method.(2005)
21.W. C. Yang, C. T. Hu, I. N. Lin, “Effect of Y2O3/MgO Co-doping on the Electrical Properties of Base-Metal-Electroded BaTiO3 Materials, J. Euro. Ceram. Soc., 24, 2004, 1479-1483.
22.F. A. Kroger and H. J. Vink, “Solid State Physics. eds. F. Seitz and D. Turnbull, Academic Press, New York, 1956.
23.Kishi, Y. Okino, M. Honda, Y. Iguchi, M. Imadeda, Y. Takahash, H. Ohsato, and T. Okuda, “The effect of MgO and rare-earth oxide on formation behavior of core-shell structure in BaTiO3, Jpn. J. Appl. Phys., 36, 5954 - 5957, (1997).
24.C. H. Kim, K. J. Park, Y. J. Yoon, M. H. Hong, J. O. Hong, and K. H. Hur, “Role of yttrium and magnesium in the formation of core-shell structure of BaTiO3 grains in MLCC, J. Eur. Ceram. Soc., 28, 1213 - 1219, (2008).
25.C. S. Chen, C. C. Chou, W. C. Yang, and I. N. Lin, “TEM microstructure of X7R type base-metal-electroded BaTiO3 capacitor materials co-doped with MgO/Y2O3 additives, Ferroelectrics, 332, 41 - 44, (2006).
26.T.Buscaglia, V. Buscaglia, and M. Viviani, “Atomistic Simulation of Dopant Incorporation in Barium Titanate, J. Am. Ceram. Soc., 84 [2], 376-84, 2001.
27.G. Y. Yang, G. D. Lian, E. C. Dickey, and C. A. Randall, “Oxygen nonstoichiometry and dielectric evolution of BaTiO3. Part II—insulation resistance degradation under applied dc bias, J. of Appl. Phys. 96, (2006).
28.J. Zhi, A. Chen, Y. Zhi, P. M. Vilarinho, and J. L. Baptista, “Incorporation of Yttrium in Barium Titanate Ceramics. J. Am. Ceram. Soc., 82 [5], 1345-48, 1999.
29.Y. H. Song, J. H. Hwang and Y. H. Han, “Effects of Y2O3 on Temperature Stability of Acceptor-Doped BaTiO3, Jpn. J. of Appl. Phys., 44, 2005, 1310-1313.
30.J. H. Kim, S. H. Yoon, and Y. H. Han, “Effects of Y2O3 Addition on Electrical Conductivity and Dielectric Properties of Ba-excess BaTiO3, J. Euro. Ceram. Soc., 2007, 1113-1116.
31.H. Lin, H. Y. Lu, “Site-Occupancy of Yttrium as a Dopant in BaO-Excess BaTiO3, Materials Science and Engineering A335, 2002, 101-108.
32.G. V. Lewis and C. R. A. Catlow, “PTCR Effect in BaTiO3, J . Am. Ceram. Soc., 68 [l0], 555-58, 1985.
33.J. N. Kim, T. S. Byun, and C. S. Kim, “Preparation of Core-Shell BaTiO3 Particles Coated with MgO, J. Chem. Eng. Jpn., 38, [8], 553-557, (2005).
34.王婉寧，氧化鎂及氧化釔添加對鈦酸鋇結構與介電性質之影響，國立成功大學資源工程研究所碩士論文，民國一百零一年。