本研究的主要目的在利用乾壓成型生胚鈦酸鋇陶瓷
體，經由兩階段的氧氣控制高溫爐來模擬多層陶瓷電容的製程，此過程著重於鈦酸鋇陶瓷體在低氧分壓力及添加受體氧化鎂(MgO)， 並藉由X 光繞射、掃瞄式(SEM)及穿透式電子顯微鏡(TEM)分析儀器觀察氧化鎂(MgO)微結構的發展， 特別是針對氧化鎂(MgO)對晶粒成長及介電特性的影響進行探討。從XRD 中觀察鈦酸鋇添加氧化鎂(MgO)，發現添加越多的氧化鎂(≥ 0.5 mol%) ， 使得鈦酸鋇由原本的正方晶(tetragonal)的結構變為疑似立方晶(pseudo-cubic)的結構;然後從SEM 觀察發現， 從原本晶粒看到的晶域(domains)隨著氧化鎂的增加而隨之減少，而且從微結構的證據也發現過量添加氧化鎂(≥ 0.5 mol%)會抑制晶粒成長。然而，是否如前人研究所報導的機制，過量的氧化鎂(≥ 0.5 mol%)而造成在晶界
上偏析(segregation)，而抑制晶粒成長，因而使得介電常數變小，還要利用後續的實驗去證實，才能建立其機制。

Commericially available BaTiO3 powder was die-pressed to discs, and sintered by a two-stage firing consisting of reducing in low oxygen partial pressures (pO2) and re-oxidizing in a higher pO2 to simulate the
industrial process of manufacturing the multi-layer ceramic capacitors(MLCC). Both undoped and MgO-doped discs as well as commercial MLCC chips, provided by Ferro Electronic Material Systems, have been investigated for sintered microstructures using the scanning electron microscopy (SEM) and transmission electron microscopy (TEM), crystalline phases using the X-ray diffractometry (XRD), and dielectric properties using the frequency response analysis. A comparison between the microstructures is made in order to look for the microstructure origin
of the macroscopic behaviour, e.g. dielectric properties.It is found that the crystalline phases have changed frompredominantly tetragonal to pseudo-cubic with MgO > 0.5 mol.%. Apart from grain growth being effectively suppressed in MgO-doped
compositions, grains containing the characteristic ferroelectric domains in undoped samples have decreased significantly in number. The indication
is that Mg2+ dissolving into the BaTiO3 lattice, substituting for the Ti4+ site reduces the c/a ratio. However, unlike what was reported before, no
direct experimental evidence is found to support that grain growth inhibition is effected by Mg2+ segregation to grain boundaries.Dislocation loops are observed ubiquitously in all samples, although bothMgO doping and low pO2 have decisive effect on their density in sintered grains. In MLCC chips, the microstructure is characterised by core-shell
grains representing the dissolution of solutes, and modulated grains representing the ordering of chemical defects, e.g. substitutional defects
and oxygen vacancies forming defect clusters.Residual pores located intragranularly in the MLCC chips are also observed, and its origin
discussed. The formation of such pores is attributed to vacancy condensation which is enhanced by the increased oxygen vacancies due to MgO doping, as an acceptor, and by low pO2 firing.

目錄
第一章 前言........................................................................... 1
第二章 文獻回顧....................................................................2
2.1 鈦酸鋇結構與特性......................................................... 2
2.2 平衡相圖....................................................................... 6
2.3 陶瓷電容器介紹............................................................11
2.4 陶瓷電容器的衰退(Degradation)現象.....................16
2.5 添加氧化鎂(MgO)對於多層陶瓷電容器的影響........20
2.6 雙晶面邊界(TPRE)之成長機制..................................21
2.7 鈦酸鋇的缺陷化學(Defect chmistry)....................... 26
第三章 實驗步驟.................................................................27
3.1 試片製作....................................................................... 27
3.2 X-ray 繞射分析............................................................ 35
3.3 光學顯微鏡(OM) ......................................................... 35
3.4 掃描式電子顯微鏡(SEM) ............................................34
3.5 穿透式電子顯微鏡(TEM) ........................................... 36
3.6 TEM 試片的準備.......................................................... 37
第四章 實驗結果與討論.................................................... 38
4.1 X-ray 繞射分析............................................................. 38
4.2 光學顯微鏡觀察........................................................... 50
4.3 掃描式電子顯微鏡觀察未添加試片............................53
4.5 穿透式電子顯微鏡觀察多層陶瓷電容器....................63
4.6 穿透式電子顯微鏡觀察鈦酸鋇在大氣下燒結........... 69
第五章 結果討論.................................................................79
第六章 結論.........................................................................82
第七章 未來工作.................................................................83
第八章 參考文獻.................................................................84
第九章 附錄.........................................................................87
9.1 JCPDS 卡號................................................................ 87
9.2 正方相立體投影圖....................................................... 88
9.3 鈦酸鋇之模擬與實際繞射圖....................................... 89
9.4 JEOL 3010AEM 校正..................................................92

1. M. S. Randall and L. A. Mann, “Modulated and ordered defect structures in electrically degraded Ni-BaTiO3 multilayer ceramics capacitors,” J. Appl. Phys., 94 [9] 5990-5996 (2003)
2. W. D. Kingery, H. K. Bowen and D. R.Uhlmann, “Dielectric Properties,” pp.913-974 in Introduction to Ceramics, 2nd ED., J. Wiley, N. Y., 1976.
3. B. Jaffee, W. R. Cook, and H. Jaffee, Peizoelectirc
Ceramics, Academic Press, N. Y., 1971
4. A. J. Moulson, and J. M.Herbert, “Electroceramics,”Chapman and Hall, 1990.
5. T. Nagai and K. Iijima, “Effect of MgO Doping on the Phase Transformations of BaTiO3,” J. Am. Ceram. Soc.,83 [1]107-112 (2000).
6. S. T. Bae, S. Lee, J. H. Kim and K. S. Hong, “Effect of Glass Composition on the dielectric properties of a liquid phase sintered MgO doped BaTiO3,” J. Am. Ceram. Soc., 91 [7] 2205-2210 (2008).
7. D. E. Rase and R. Roy, “Phase Equilibrium in the System BaO-TiO2,”J. Am. Ceram. Soc., 38 [3] 102-113 (1955).
8. H. M. O'Bryan, Jr. and J. Thomson, ”Phase Equilibria in the TiO2-Rich Region of the system BaO-TiO2,” J. Am. Ceram. Soc., 57 [12] 522-26 (1974).
9. T. Negas, R. S. Roth, H. S. Parker and D. Minor, “Subsolidus Phase
Relations in the BaTiO3-TiO2 System,” J. Sol. Stst. Chem., 9, 297-307(1974).
10. J. A. E. Javadpour, “Raman Spectroscopy of Higher Titanate Phase in the Barium Titanate-Titanium Oxide System,” J. Am. Ceram. Soc., 71
[4] 206-213 (1988).
11. J. J. Ritter, R. S. Roth and J. E. Blendell, “Alkoxide Precursor Synthesis and Characterization of Phases in Barium-Titanium Oxide System ,” J. Am. Ceram. Soc., 69 [2] 155-162 (1986).
12. K. W. Kirby, “Phase Relations in the Barium Titanate-Titanium Oxide System,” J. Am. Ceram. Soc., 74 [4] 206-213 (1988).
13. S. Lee and C. A. Randall, “Modified Phase Diagram for the Barium Dioxide System for the Ferroelectric Barium Titanate,”J. Am. Ceram.
Soc., 90 [8] 2589-2595 (2007).
14. Electrical Industry Alliance (EIA), World Capacitor Trade Statistics (WCTS) (2002).
15. Y. Taho and V. O. Ronald, “Robust Design for a Multilayer Ceramic Capacitor Screen-Printing Process Case Study,” J. Eng. Design, 15 447-457 (2004).
16. H. Kishi, Y. Mizuno and H. Chazono, “Base-Metal
Electrode-Multilayer Ceramic Capacitor:Past, Present and Future Perspectives,” Jpn. J. Appl. Phys., 42 [1] 1-15 (2003).
17. H. Chazono and H. Kishi, “dc-Electrical Degradation of the BT-Based Material for Multilayer Ceramics Capacitor with Ni internal
Electrode:Impedance Analysis and Microstucture,” Jpn. J. Appl. Phys. 40 [9B] 5624-5629 (2001).
18. G. Y. Yang, G. D. Lian, E. C. Dickey and C. A. Randall, “Oxygen nonstoichiometry and dielectric evolution of BaTiO3.Part II-resistance
degradation under applied dc bias,” J. Appl. Phys., 96 [12] 7500-7508 (2004).
19. Y. C. Wu, S. F. Wang, D. E. McCauley, S. H. Chu and H. Y. Lu,”Dielectric Behavior and second phases in X7R-formulated BaTiO3 sinteded in low-oxygen partial pressures.” J. Am. Ceram. Soc.,
90 [9] 2926-2934 (2007).
20. J. Jeong and Y. H. Han, “Effects of MgO-Doping on ElectricalProperties and Microstructure of BaTiO3,
”Jpn. J. Appl. Phys., 43 [8A]
5373-5377 (2004).
21. J. H. Hwang, S. K. Choi and Y. H. Han, “Dielectric Properties of BaTiO3 coped with Er2O3 and MgO,” Jpn. J. Appl. Phys., 40 [8] 4952-4955 (2001).
22. T. Nagai, K. Lijima H. J. Hwang, M. Sando, T. Sekino and K. Nihara,“Effect of MgO Doping on the Phase Transformations of BaTiO3,” J.
Am. Ceram. Soc., 83 [1] 107-112 (2000).
23. H. Oppolzer and H. Schmelz, “Inverstigation of Twin Lamellase in BaTiO3 Ceramics,”Investigation of Twin Lamellae in BaTiO3 Ceramics,” J. Am. Ceram. Soc., 66 [7] 444-447 (1983).
24. H. Y. Lee and J. S. Kim, “Effect of Twin-Plane Reentrant Edge on the Coarsening Behavior of Barium Titanate Grains,” J. Am. Ceram.
Soc.,85 [4] 977-980 (2002).
25. Y. C. Wu, C. C. Lee and H. Y. Lu, “The {111} Growth Twins in tetragonal Barium Titanate,” J. Am. Ceram. Soc., 85 [5] 1679-1686
(2006).
26. D. R. Clarke, “Observation of Microcracks and Thin Intergranular Films in Ceramics by Transmission Electron Microscopy,” J. Am.
Ceram. Soc., 63 [1] 104-106 (1980)
27. Y. C. Wu, C. Y. Chen, H. Y. Lu, D. E. McCauley and Mike S. H. Chu,“dislocation loops in pressureless-sintered undoped BaTiO 3 Ceramics,” J. Am. Ceram. Soc., 85 [5] 2213-2219 (2006).
28. D. E. McCauley, Mike S. H. Chu and M. H. Megherhi, “pO2 Dependence of the diffuse-Phase Transition in Base Metal Capacitor
Dielectrics,” J. Am. Ceram. Soc., 89 [1] 193-201(2006).
29. N. H. Chen, R. K. Sharma and D. M. Smyth, “nonstoichiometry in
undoped BaTiO3,” J. Am. Ceram. Soc., 64 [9] 556-562 (1981).