商用電容器的應用略分為EIA之Y5V、Z5U、X7R等規格，其中以X7R的規格最為嚴謹。高溫型電容器X8R則專位汽車工業用途以及其他高溫工作環境的設備而開發。
本研究中發現，當BaCO3添加量較少時會造成晶粒成長，添加物在晶粒與晶界間沒有明顯的濃度梯度產生，介電常數與溫度的曲線呈現出一明顯的介電峰值；當BaCO3添加量較多時晶粒成長受到抑制，添加物在晶粒與晶界間有明顯的濃度梯度產生，呈現出較為平坦的介電常數與溫度之曲線。文獻中指出當晶粒外層之單位體積內添加物濃度較高時，可使介電常數與溫度的曲線平坦化，並符合X8R工業規格，因此在此系統中晶粒外層之單位體積內添加物濃度較高與添加物的成份分布不均為介電常數與溫度的曲線之平坦化機制。

Commercial ceramic capacitors for application, can be briefly classified into Y5V, Z5U, X7R for EIA. Especially, it is the severest for X7R specification. The high temperature capacitor, X8R is made for automotive applications and other high temperature working environment.
In this research, the grain growth of BaTiO3 occurred and no obvious concentration gradient of the dopants between the grain and grain boundary was observed for the sample added with a small amount of BaCO3. The ε-T curves demonstrated a obvious Tc peak. However, in the case of the samples added with the higher amount of BaCO3, the concentration gradient of the dopants between the grain and grain boundary was observed, which resulted in flattening of temperature coefficient of capacitance curve and satisfaction the X8R requirements. In this system, the mechanism of the stable temperature-capacitance characteristics may be resulted from the higher concentration of dopants per unit volume in the outer grain and the composition fluctuation.

1. J. Nowotny, “Electronic Ceramic Materials,” (1991)
2. 邱碧秀, “電子陶瓷材料,” (1988).
3. A. J. Moulson and J. M. Herbert, “Electroceramics,” Chapman & Hall (1990).
4. D. E. Rase and R. Roy, “Phase equilibria in the system BaO–TiO2,” J. Am. Ceram. Soc., Vol. 38, Issue 3, pp. 102-113 (1955).
5. R. K. Sharma, N. H. Chan and D. M. Smyth, “Solubility of TiO2 in BaTiO3,“ J. Am. Ceram. Soc., Vol. 64, Issue 8, pp. 448-451 (1981).
6. Y. H. Hu, M. P. Harmer and D. M. Smyth, “Solubility of BaO in BaTiO3,“ J. Am. Ceram. Soc., Vol. 8, Issue 7, pp. 372-376 (1985).
7. K. W. Kirby and B. A. Wechsler, “Phase relations in the barium titanate—titanium oxide system,“ J. Am. Ceram. Soc., vol. 74, Issue 8, pp. 1841-1847 (1991).
8. A. K. Maurice and R. C. Buchanan, “Preparation and stoichiometry effect on microstructure and properties of high purity BaTiO3,” Ferroelectrics, Vol. 74, pp. 61-75 (1987).
9. J. D. Murray, “Some causes and effects of phases other than tetragonal BaTiO3 in barium titanate,” Am. Ceram. Soc. Bull., Vol. 37, pp. 476-479 (1958).
10. A. Beauger, J. C. Mutin, J. C. Niepce, ”Role and behaviour of orthotitanate Ba2TiO4 during the processing of BaTiO3 based ferroelectric ceramics,” J. Mater. Sci., Vol. 19, pp. 195-201 (1984).
11. J. K. Lee and K. S. Hong, ”Role of Ba/Ti ratios in the dielectric properties of BaTiO3 ceramics,” J. Am. Ceram. Soc., Vol. 84, Issue 9, pp. 2001-2006 (2001).
12. W. D. Kingery, H. K. Bowen and D. R. Uhlmann, “Introduction to Ceramics,” 2nd Edition , John Wiley & Sons , New York (1976).
13. K. Uchino, E. Sadanaga and T. Hirose, ”Dependence of the crystal structure on particle size in barium titanate,” J. Am. Ceram. Soc., Vol. 72, Issue 8, pp. 1555-1558 (1989).
14. G. Arlt , D. Hennings , and G. With, “Dielectric properties of fine-grained barium titanate ceramics,“ J. Appl. Phys., Vol. 58, pp. 1619-1625 (1985).
15. R. J. Brandmayr et al., USA ECOM Technical Report 2614, May 1965.
16. A. Yamaji, Y. Enomoto, K. Kinoshita and T. Murakami, “Preparation, characterization, and properties of Dy-doped small-grained BaTiO3 ceramics,” J. Am. Ceram. Soc., Vol. 60, Issue 3-4, pp. 97-101 (1977).
17. A. J. Bell, A. J. Moulson and L. E. Cross, “The effect of grain size on the permittivity of BaTiO3,” Ferroelectrics, Vol.54, 147-150 (1984).
18. T. T. Fang, H. L. Hsieh, F. S. Shiau, “Effect of pore morphology and grain size on the dielectric properties and tetragonal-cubic phase transition of high purity barium titanate,” J. Am. Ceram. Soc., Vol. 76, Issue 5, pp. 1205-1211 (1993).
19. M. W. Barsoum, “Fundamentails of Ceramics,” pp. 513-543 (1997).
20. J. M. Herbert, “Ceramic Dielectrics and Capacitors,“ New York, pp. 202-218 (1985).
21. G. C. Jain, “Properties of Electrical Engineering Materials,“ (1966).
22. J. N. Lin and T. B. Wu, “Effect of isovalent substitutions on lattice softening and transition character of BaTiO3 solid solutions,” J. Appl. Phys., Vol. 68, pp. 985-993 (1990).
23. H. Ihrig, “The phase stability of BaTiO3 as a function of doped 3d element: an experimental study,” J. Phys. C., Vol. 11, pp. 819-827 (1978).
24. D. Hennings and A. Schnell, “Diffuse ferroelectric phase transitions in Ba(Ti1-yZry)O3 ceramics,” J. Am. Ceram. Soc., Vol. 65, Issue 11, pp. 539-534 (1982).
25. J. H. Hwang and Y. H. Han, “Electrical properties of cerium-doped BaTiO3,” J. Am. Ceram. Soc., Vol. 84, Issue 8, pp. 1750-1754 (2001).
26. S. S. Yukie, N. A. Sato and T. Nomura , “Effect of Y-doping on resistance degradation of multilayer ceramic capacitors with Ni electrodes under the highly accelerated life test,“ Jpn. J. Appl. Phys., Vol. 36, pp. 6016-6020 (1997).
27. S. B. Desu and E. C. Subbarao, “Effect of oxidation states of Mn on the phase stability of Mn-doped BaTiO3,” Ferroelectrics, Vol. 37, pp. 665-668 (1981).
28. D. F. K. Hennings, “Dielectric materials for sintering in reducing atmospheres,” J. Eur. Ceram. Soc., Vol. 21, pp. 1637-1642 (2001).
29. L. A. Xue , Y. Chen and R. J. Brook, ”The influence of ionic radii on the incorporation of trivalent dopants into BaTiO3,” Mater. Sci. Engin., B1, pp. 193-201 (1988).
30. H. Kishi, N. Kohzu, Y. Mizuno, Y. Iguchi, J. Sugino, H. Ohsato and T. Okuda, ”Effect of occupational sites of rare-earth elements on the microstructure in BaTiO3,”Jpn. J. Appl. Phys. Vol. 38, pp. 5452-5456 (1999).
31. S. Sato, T. Nomura and A. Sato, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,226,172 (2001).
32. S. Sato, Y. Fujikawa and Y. Terada, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,403,513 (2002).
33. S. Sato, Y. Fujikawa and Y. Terada, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,544,916 (2003).
34. S. Sato, Y. Fujikawa and Y. Terada, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,548,437 (2003).
35. Y. Fujikawa, Y. Terada and S. Sato, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,559,084 (2003).
36. Y. Fujikawa, Y. Terada and S. Sato, “Dielectric Ceramic Composition and Electronic Device,” US Patent 6,699,809 (2004).
37. Y. S. Jung, E. S. Na, U. Paik, J. Lee and J. Kim, ”A study on the phase transition and characteristics of rare earth element doped BaTiO3,” Mater. Res. Bull., Vol. 37, pp.1633-1640 (2002).
38. E. Na, S. C. Choi and U. Paik, ”Temperature dependence of dielectric properties of rare-earth element doped BaTiO3,” J. Ceram. Pro. Res., Vol. 4, No.4, pp.181-184 (2003).
39. S. Sato, Y. Fujikawa and T. Nomura, “Effect of rare-earth doping on the temperature-capacitance characteristics of MLCCs with Ni electrodes,” Dielectric Materials and Devices, pp.473-481 (2000).
40. Y. Li, X. Yao and L. Zhang, “High permittivity neodymium-doped barium titanate sintered in pure nitrogen,” Ceram. Inter., Vol. 30, pp.1325-1328 (2004).
41. S. Wang, S. Zhang, X. Zhou, B. Li and Z. Chen, ”Effect of sintering atmosphere on the microstructure and dielectric properties of Yb/Mg co-doped BaTiO3 ceramics,” Mater. Lett., Vol. 59, pp. 2457-2460 (2005).
42. Y. H. Song, J. H. Hwang and Y. H. Han, ”Effect of Y2O3 on temperature stability of acceptor-doped BaTiO3,” Jpn. J. Appl. Phys., Vol. 44, No. 3, pp. 1310-1313 (2005).
43. Y. H. Song and Y. H. Han, ”Effects of rare-earth oxides on temperature stability of acceptor-doped BaTiO3,” Jpn. J. Appl. Phys., Vol. 44, No. 8, pp. 6143-6147 (2005).
44. S. Zhang, S. Wang, X. Zhou, B. Li and Z. Chen, “Influence of 3d-elements on dielectric properties of BaTiO3 ceramics,” J. Mater. Sci.: Mater. electro., Vol. 16, pp. 669-672 (2005).
45. S. Wang, S. Zhang, X. Zhou, B. Li and Z. Chen, “Investigation on dielectric properties of BaTiO3 co-doped with Ni and Nb,” Mater. Lett., Vol. 60, pp. 909-911 (2006).
46. B. S. Rewal, M. Kahn and W. R. Buessem, “Grain core-grain shell structure in barium titanate-based-dielectric,” pp. 172-188 in Advances in Ceramics, Vol. 1, Grain Boundary Phenomena in Electronic Ceramics. Edited by L. M. Levinson. American Ceramic Society, Columbus, OH, 1981.
47. J. S. Kim and S. J. Kang, “Formation of core-shell structure in the BaTiO3-SrTiO3 system,” J. Am. Ceram. Soc., Vol. 82, Issue 4, pp. 1085-1088 (1999).
48. N. Setter and L. E. Cross, “The role of B-site cation disorder in diffuse phase transition behavior of perovskite ferroelectrics,” J. Appl. Phys., Vol. 51, No. 8, pp. 4356-4360 (1980).
49. G. A. Smolenskii, A. I. Agranovskaya and V. A. Isupov, “New ferroelectrics of complex compound,” Sov. Phys. Solid State., Vol. 1, pp. 907-908 (1959).
50. D. Hennings and R. Rosenstein, “Temperature-stable dielectrics based on chemically inhomogeneous BaTiO3,” J. Am. Ceram. Soc., Vol. 67, Issue 4, pp. 249-254 (1984).
51. H. Y. Lu, J. S. Bow and W. H. Deng, “Core-shell structure in ZrO2-modified BaTiO3 ceramics,” J. Am. Ceram. Soc., Vol. 73, Issue 12, pp. 3562-3568 (1990).
52. H. T. Martirena and J. C. Burfoot, “Grain-size effects on properties of some ferroelectric ceramics,” J. Phys., c7, pp. 3182-3192 (1974).
53. W. R. Beussem, L. E. Cross and A. K. Goswami, “Phenomenological theory of high permittivity in fine-grained barium titanate,” J. Am. Ceram. Soc., Vol. 49, Issue 1, pp. 33-36 (1966).
54. W. R. Beussem, L. E. Cross and A. K. Goswami, “Effect of two-dimensional pressure on the permittivity of fine and coarse-grains barium titanate,” J. Am. Ceram. Soc., Vol. 49, Issue 1, pp. 36-39 (1966).
55. P. Murugaraj, T. N. Kutty and M. S. Rao, “Diffuse phase transformation in neodymium-doped BaTiO3 ceramics,” J. Mater. Sci., Vol. 21, pp. 3521-3527 (1986).
56. L. Benguigui and K. Bethe, ”Diffused phase transition in BaxSr1-xTiO3 single crystal,” J. Appl. Phys., Vol. 47, No. 7, pp. 2787-2791 (1976).
57. D. Bard, E. Barbulescu and A. Barbulescu, “Diffuse phase transitions and ferroelectric-paraelectric diagram for the BaTiO3-SrTiO3 system,” Phys. Stat. Sol. (a), Vol. 74, pp. 79-83 (1982).
58. T. R. Armstrong, L. E. Morgens, A. K. Maurice and R. C. Buchanan, “Effects of zirconia on microstructure and dielectric properties of barium titanate ceramics,” J. Am. Ceram. Soc., Vol. 72, Issue 4, pp. 605-611 (1989).
59. H. Chazono, H. Kishi, “Sintering characteristics in BaTiO3-Nb2O5-Co3O4 ternary system: I, electrical properties and microstructure,” J. Am. Ceram. Soc., Vol. 82, Issue 10, pp. 2689-2697 (1999).
60. H. Chazono, H. Kishi, “Sintering characteristics in BaTiO3-Nb2O5-Co3O4 ternary system: II, stability of so-called ‘core-Shell’ Structure,” J. Am. Ceram. Soc., Vol. 83, Issue 1, pp. 101-106 (2000).
61. T. R. Armstrong and R. C. Buchanan, ”Influence of core-shell grains on the internal stress state and permittivity response of zirconia-modified barium titanate,” J. Am. Ceram. Soc., Vol. 73, Issue 5, pp. 1268-1273 (1990).
62. T. Takeuchi, K. Ado, T. Asai, H. Kageyama, Y. Saito, C. Masquelier and O. Nakamure, “Thickness of cubic surface phase on barium titanate single-crystalline grains,” J. Am. Ceram. Soc., Vol. 77, Issue 6, pp. 1665-1668 (1994).
63. G. Liu, X. Wang, Y. Lin, L. T. Li and C. W. Nan, “Growth kinetics of core-shell-structured grains and dielectric constant in rare-earth doped BaTiO3 ceramics,” J. Appl. Phys., Vol. 98, pp. 044105 (2005).
64. D. E. McCauley, M. S. H. Chu, and M. H. Megherhi, “PO2 dependence of the diffuse-phase transition in base metal capacitor dielectrics,” J. Am. Ceram. Soc., Vol. 89, Issue 1, pp. 193-201 (2006).
65. Q. Feng, C. J. McConville and D. D. Edwards, “Effect of oxygen partial pressure on the dielectric properties and microstructures of cofired base-metal-electrode multilayer ceramic capacitors,” J. Am. Ceram. Soc., Vol. 89, Issue 3, pp. 894-901 (2006).
66. 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., Vol. 87, Issue 10, pp. 1945-1951 (2004).
67. Y. Mizuno, Y. Okino, N. Kohzu, H. Chazono and H. Kishi, “Influence of the microstructure evolution on electrical properties of multilayer capacitor with Ni electrode,” Jpn. J. Appl. Phys., Vol. 37, pp. 5227-5231 (1998).