在工業上的積層陶瓷電容器為了因應堆疊技術的進步且為了降低生產成本，選用了卑金屬作為積層陶瓷電容器內部的電極(Base metal Electrode, BME)，而為了防止卑金屬氧化，會在還原氣氛中進行燒結，而鈦酸鋇陶瓷體於還原氣氛中燒結，容易使陶瓷體半導化，進而影響其絕緣電阻率，而為了改善此現象設計加入低價離子取代高價離子，形成受體補償並抑制半導化。而在氣氛燒結的過程也容易使晶粒形成異常的晶粒成長，而透過富鋇成分的設計，可以抑制異常的晶粒成長，使晶界分率提升。
本研究設計利用固態反應法進行合成鎂摻雜鈦酸鋇Bam(Ti1-xMgx)O3-x，成分點為鋇鈦比m=0.997, 1.000, 1.003, 1.005，鎂離子取代鈦離子x=0.04，藉由不同鋇鈦比的設計了解鎂離子取代鈦位置後對晶體結構、晶格參數、拉曼光譜、比表面積、顯微結構以及介電性質之影響與關係，進而探討此材料在積層陶瓷電容應用之可行性。
研究之結果顯示，可以透過二階段煅燒成功控制粒徑合成符合工業規格500 nm的鎂摻雜鈦酸鋇粉末，且在成份點m=0.997, 1.000, 1.003, 1.005於煅燒後呈現六方與正方晶相同時存在的表現，並透過Rietveld refinement精算得知，當Mg2+進入鈦酸鋇後，單位晶格內的a 軸會伸長、c 軸會縮短，造成正方性下降，且其六方晶相的表現為鎂離子取代鈦離子位置產生氧空缺造成晶體結構的排列層序改變所造成; 而在拉曼分析也表明，其結構為六方與正方的共存，並具有氧空缺的震動模式。而在陶瓷體分析顯微結構、結晶相分析與拉曼分析的結果中發現，在還原氣氛下燒結後其結晶相變回正方晶相為主並含有少量的六方相，因其氧空缺的缺陷在於氣氛燒結時身為受體而被補償，同時這樣的機制也有效抑制了陶瓷體半導化的產生; 鎂離子的添加容易使陶瓷體形貌呈現立體狀，發現於m=1.005, x=0.04樣品，燒結後具有較多六方晶相的析出形成二次相，與陶瓷體顯微結構觀察到相同的結果，而鋇鈦比的提升有效抑制晶粒成長，使晶界分率提升，並使絕緣電阻率於m=1.003樣品達到2.4*10^10 (Ω•m)之值; 在介電性質方面，Mg2+添加會使鐵電性降低，得到較低的介電常數，居禮溫度也會同時往低溫移動，且具有六方相影響陶瓷體的極化機制並於電容溫度曲線的觀察得知在燒結緻密時會使core-shell structure的分布改變，形成shell較厚的低溫段上翹與高溫段因極化能力降低而向下變化的表現。

In this study, the solid-state reaction method was used to synthesize magnesium-doped barium titanate Bam(Ti1-xMgx)O3-x, m = 0.997-1.005, x = 0.04. Through the design of different barium-titanium ratios, the influence and relationship of magnesium ions to replace titanium position on crystal structure, lattice parameters, Raman spectrum, specific surface area, microstructure and dielectric properties were investigated, and then the application of this material in multilayer ceramic capacitors was discussed feasibility of application. The results of the research show that the magnesium-doped barium titanate powder can be successfully synthesized by controlling the particle size through two-stage calcination to meet the industrial specification of 500 nm, and at the composition point m=0.997, 1.000, 1.003, 1.005 After calcination, hexagonal and tetragonal crystals are presented. The same performance exists at the same time, and through Rietveld refinement actuarial calculation, it is known that the performance of its hexagonal crystal phase is caused by the substitution of magnesium ions for titanium ions and the generation of oxygen vacancies. In the results of microstructure analysis, crystal phase analysis and Raman analysis of the ceramic body, it is found that after sintering in a reducing atmosphere, the crystal phase changes back to mainly tetragonal phase and contains a small amount of hexagonal phase, and the improvement of barium-titanium ratio is effective. Inhibit the grain growth, increase the grain boundary fraction, and make the insulation resistivity of the m=1.003 sample reach the value of 2.4*1010 (Ω•m); in terms of dielectric properties, the addition of Mg2+ will reduce the ferroelectricity, and obtain with a lower dielectric constant, the Curie temperature will also move to a low temperature, and the hexagonal phase affects the polarization mechanism of the ceramic body. The observation of the capacitance temperature curve shows that the sintering and densification will change the distribution of the core-shell structure. The low-temperature section with thicker shells upturns and the high-temperature section changes downwards.

1. W.-D. Kingery, H.-K. Bowen, and D.-R. Uhlmann, Introduction to Ceramics, America: John wiley & sons, (1976).
2. B. Jaffe, W.-R. Cook, Jr. and H. Jaffe, Piezoelectric Ceramics, William R. Cook, Jr. and Hans Jaffe Gould Inc., Cleveland, Ohio, U. S. A., (1971).
3. 吳朗，電工材料: 全華圖書，(2012).
4. L.-C. Dufour and C. Monty, Surfaces and Interfaces of Ceramic Materials: Springer Science & Business Media, (2012).
5. D. Rase and R. Roy, “Phase Equilibria in the System BaO–TiO2,” Journal of the American Ceramic Society, vol. 38, no. 3, pp. 102-113, (1955).
6. K. Maurice and R.-C. Buchana, “Preparation and Stoichiometry Effects on Microstructure and Properties of High Purity BaTiO3,” Ferroelectrics, 74 61-75, (1987).
7. K. Kiss, J. Magder, M.-S. Vukasovich, and R.-J. Lockhart, “Ferroelectrics of Ultrafine Particle Size: I, Synthesis of Titanate Powders of Ultrafine Particle Size,” J. Am.Ceramic. Soc., 49 [6], 291-295 (1966).
8. 張哲源，以尿素-硝酸鋇沉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，(2007)。
9. L. C. Dufour, C. Monty, and G. P. Ervas., Surfaces and Interfaces of Ceramic Materials; pp. 521-533, Kuwer Academic, Boston, (1989).
10. S. Aoyagi, Y. Kuroiwa, A. Sawasada, I. Yamashita, and T. Atake, “Composite Structure of BaTiO3 Nanoparticle Investigated by SR X-Ray Diffraction,” J. Phys. Soc. Jpn., 71 [5] 1218-1221, (2002).
11. G. Arlt, D. Hennings, and G. De With, “Dielectric Properties of Fine‐Grained Barium Titanate Ceramics,” Journal of Applied Physics, vol. 58, no. 4, pp.1619-1625, (1985).
12. 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 [8] 2589-2594, (2007).
13. S. Lee, Z.-K. Liu, M.-H. Kim, and C.-A. Randall, “Influence of Nonstoichiometry on Ferroelectric Phase Transition in BaTiO3,” J. Appl. Phys., 101, 054119 (2007).
14. 杜明婷，鋇鈦比對鈦酸鋇粉末晶粒大小及結晶相之影響。國立成功大學資源工程研究所碩士論文，(2008)
15. N.-M. Hwang, S.-H. Yoon, J.-H. Lee, and D.-Y. Kim, “Effect of the Liquid-Phase Characteristic on the Microstructures and Dielectric Properties of Donor- (Niobium) and Acceptor- (Magnesium) Doped Barium Titanate,” J. Am. Ceram. Soc., 86 [1] 88-92 (2003).
16. R. Sharma, N.-H. Chan, and D. Smyth, “Solubility of TiO2 in BaTiO3,” Journal of the American Ceramic Society, vol. 64, no. 8, pp. 448-451, (1981).
17. P.-E. Rubavathi, M.-V.-G Babu, B. Bagyalakshmi, L. Venkidu, D. Dhayanithi, N.-V. Giridharan, B. Sundarakannan, Impact of Ba/Ti ratio on the magnetic properties of BaTiO3 ceramics, Vacuum, Volume 159, Pages 374-378, (2019).
18. C.-G. Bergeron and S.-H. Risbud, Introduction to Phase Equilibria in Ceramics, America: Wiley, (1984).
19. R.-D. Shannon, “Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides,” Acta Crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography, vol. 32, no. 5, pp. 751-767, (1976).
20. Zhi, A. Chen, Y. Zhi, P.-M. Vilarinho, and J.-L. Baptista, Incorporation of yttrium in barium titanate ceramics. Journal of the American Ceramic Society, 82(5), pp.1345-1348, (1999).
21. M.-K. Buscaglia, M. Viviani, V. Buscaglia, C. Bottino, and P. Nanni, Incorporation of Er3+ into BaTiO3. Journal of the American Ceramic Society, 85(6), pp.1569-1575, (2002).
22. Muller and R. Roy, The Major Ternary Structural Families, Berlin-Heidelberg-New York: Springer-Verlag, (1974).
23. C. Schinzer, "Distortion of Perovskites," Retrieved, (2012).
24. J. Lin and T. Wu, “Effects of Isovalent Substitutions on Lattice Softening and Transition Character of BaTiO3 solid Solutions,” Journal of Applied Physics, vol. 68, no. 3, pp. 985-993, (1990).
25. D. Hennings, A. Schnell, and G. Simon, “Diffuse Ferroelectric Phase Transitions in Ba(Ti1‐yZry)O3 Ceramics,” Journal of the American Ceramic Society, vol. 65, no. 11, pp. 539-544, (1982).
26. D. Makovec, Z. Samardžija, U. Delalut, and D. Kolar, “Defect Structure and Phase Relations of Highly Lanthanum‐Doped Barium Titanate,” Journal of the American Ceramic Society, vol. 78, no. 8, pp. 2193-2197, (1995).
27. S. Sato, Y. Nakano, A. Sato, and T. Nomura, “Effect of Y-Doping on Resistance Degradation of Multi-Layer Ceramic Capacitors With Ni Electrodes under the Highly Accelerated Life Test,” Japanese Journal of Applied Physics, vol. 36, no. 9S, pp. 6016, 1997.
28. L.-A. Xue, Y. Chen, and R.-J. Brook, “The Influence of Ionic Radii on the Incorporation of Trivalent Dopants into BaTiO3,” Materials Science and Engineering: B, vol. 1, no. 2, pp. 193-201, (1988).
29. J. Jeong and Y.-H. Han, “Effects of MgO-Doping on Electrical Properties and Microstructure of BaTiO3,” Japanese Journal of Applied Physics, vol. 43, no. 8R, pp. 5373, (2004).
30. M.-T. Buscaglia, V. Buscaglia, M. Viviani, and P. Nanni, “Atomistic Simulation of Dopant Incorporation in Barium Titanate,” Journal of the American Ceramic Society, vol. 84, no. 2, pp. 376-84, (2001).
31. T. Nagai, K. Iijima, H.-J. Hwang, M. Sando, T. Sekino, and K. Niihara, “Effect of MgO Doping on the Phase Transformations of BaTiO3,” Journal of the American Ceramic Society, vol. 83, no. 1, pp. 107-12, (2000).
32. S.-T. Bae, D.-K. Yim, K.-S. Hong, J.-S. Park, H. Shin, and H.-S. Jung, “Role of Liquid Phase in Achieving a Fine Microstructure and Diffusive Phase Transition of MgO‐Doped BaTiO3,” International Journal of Applied Ceramic Technology, vol. 6, no. 6, pp. 679-686, (2009).
33. F. Kröger and H. Vink, Solid State Physics, New York: Academic Press, (1956).
34. B.-N. Ezealigo, C.-E. Ekuma, Influence of vacancy defect on the structural and optical properties of hexagonal barium titanate ceramics: Experimental and theoretical analysis, Materials Letters, Volume 304, 130582, ISSN, 0167-577X, (2021).
35. C.-F. Chen, G. King, R.-M. Dickerson, P.-A. Papin, S. Gupta, W.-R. Kellogg, G. Wu, Oxygen-deficient BaTiO3−x perovskite as an efficient bifunctional oxygen electrocatalyst, Nano Energy, Volume 13, Pages 423-432, ISSN 2211-2855, (2015).
36. Saburi, Properties of semiconductive barium titanates. Journal of the physical Society of Japan, 14(9), pp.1159-1174, (1959).
37. G. Burns and B. A. Scott, “Lattice Modes in Ferroelectric Perovskites: PbTiO3,” Physical Review B, vol. 7, no. 7, pp. 3088, (1973).
38. J. Freire and R. Katiyar, “Lattice Dynamics of Crystals with Tetragonal BaTiO3 Structure,” Physical Review B, vol. 37, no. 4, pp. 2074, (1988).
39. J.-T. Last, “Infrared-Absorption Studies on Barium Titanate and Related Materials,” Physical Review, vol. 105, no. 6, pp. 1740, (1957).
40. U.-D. Venkateswaran, V.-M. Naik, and R. Naik, “High-Pressure Raman Studies of Polycrystalline BaTiO3,” Physical Review B, vol. 58, no. 21, pp. 14256, (1998).
41. J. AKIMBO, Y.-G. OOSAWA, Refinement of Hexagonal BaTiO3, National Institute of Materials and Chemical Research, Higashi, Tsukuba, Ibaraki 305, Japan, Received 17May, accepted13August, (1993).
42. B. Poojitha , A. Kumar , A. Rathore , S. Saha , Correlations between the structural, magnetic, and ferroelectric properties of BaMO3: M 1⁄4 Ti1-x(Mn/Fe)x compounds: A Raman study, Department of Physics, Indian Institute of Science Education and Research, Bhopal, 462066, India,(2020).
43. C. Larson and R. B. Von Dreele, General Structure Analysis System (GSAS), New Mexico: Los Alamos National Laboratory, (2004).
44. T. Nishino, “Formation Process of Metastable Phase (δ) of Alkaline‐Earth Carbonate,” Journal of the American Ceramic Society, vol. 70, no. 7, pp. C‐ 162-C‐164, (1987).
45. 張育綸，鹼土碳酸鹽與氧化物的固態反應過程中相生成及物質擴散之研究，資源工程學系碩博士班，國立成功大學，台南市，(2010).
46. 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，資源工 程學系碩博士班，國立成功大學，台南市，(2012).
47. 張哲源，鈦酸鋇介電陶瓷之成分調整與結構及電容率平坦化的關聯，資源工程學系碩博士班，國立成功大學，台南市，(2013).
48. R. Machado, Structural, electrical, magnetic and magnetoelectric properties of Fe doped BaTiO3 , Ceramics International 42 (2016), 8010–8016, (2016).
49. C.Y Su, M-T Tu, C.-T. Lee, and C.-Y. Huang, Effect of Ba/Ti Ratio on Crystallite Size and Crystalline Phase of BaTiO3 Powders. 日本セラミックス協会年会・秋季シンポジウム 講演予稿集, pp.8-8, (2009).
50. N.-V. Dang, N.-T. Dung, P.-T. Phong, I.-J. Lee, Effect of Fe3+ substitution on structural, optical and magnetic properties of barium titanate ceramics, Physica B: Condensed Matter, Volume 457, Pages 103-107, ISSN 0921-4526, (2015).
51. D.-P. Dutta, M. Roy, N. Maiti, A.-K. Tyagi, Phase evolution in sonochemically synthesized Fe 3+ doped BaTiO3 nanocrystallites: structural, magnetic and ferroelectric characterisation. Physical Chemistry Chemical Physics, 18(14), 9758-9769, (2016).
52. S.-C. Jeon, B.-K. Yoon, K.-H. Kim, S.-J.-L. Kang, Effects of core/shell volumetric ratio on the dielectric-temperature behavior of BaTiO3. Journal of Advanced Ceramics, 3(1), 76-82. (2014).