ZnNb2O6材料為鈳鐵礦結構 (columbite)。此材料之燒結溫度約在1000-1200°C，且具有良好的微波介電性質。
在近幾十年來有許多文獻探討鈳鐵礦結構 M+Nb2O6，但大多數研究均集中探討以不同元素取代 M+，所造成性質之改變。而過去研究指出，添加少量 Ta5+於 ZnNb2O6 中，能夠完全固溶於結構中並形成 Zn(Nb1-xTax)2O6 成份系統。
故本研究以 x=0-0.1 之Ta5+ 少量取代 Nb5+，形成純相之固溶體 Zn(Nb1-xTax)2O6，探討其晶體結構、微結構與微波介電性質的關係。
在本實驗燒結條件為升溫速率 5°C / min 升到 1150 °C，並持溫 2 小時情況下，不同成份點之微結構、粒徑大小和密度皆無明顯的改變 (相對密度變化在 96.1% 至 96.7% 之間)，但其微波介電性質 Q×f 有大幅度的改變。
而介電常數 (r) 由 x=0 時 22.9 提升至 23.1 (x=0.05)，雖有增加，但變化之幅度不明顯。但當x=0時 Q×f 值為 80,000，而在 x=0.05 時提升至 130,000 (at 8.81 GHz)，而添加 Ta5+ 至 x=0.1 時，Q×f 值下降至 88,000。
在晶體結構部分：鈳鉭鐵礦 (ixiolite)具有鈳鐵礦類似之結構，且可視為鈳鐵礦之無序結構，而在前人文獻指出，當鈳鉭鐵礦轉變為鈳鐵礦時會出現 (040) 繞射面。從長時間 X 光繞射光譜計算可知，在 x=0.05 時，有序程度 (I040/ I040+ I031) 較 x=0 時有些微上升；從 9.84 升至13.41，故推測 Q×f 值上升與結構之有序程度有關。

ZnNb2O6 with a columbite crystal structure have good microwave dielectric properties and sintered temperature about 1000-1200°C. The binary niobate compounds with general formula M+Nb2O6 was interested in last decade, and most of articles focus how the M+ effects dielectric properties of M+Nb2O6. In the past study, it is substituting small amount Nb5+ with Ta5+ of the ZnNb2O6 ceramics can forming solid solution Zn(Nb1-xTax)2O6.
At this study sintering condition (sintering temperature 1150°C for 2 h), by increasing x, not only the microstructure, grain size but relative density (change from 96.1% to 96.7%) have not change obviously. But the Q×f (at 8.81 GHz) be tremendously boosted from 80,000 GHz at x= 0 to a maximum 130,000 GHz at x=0.05. On the other hand, Q×f decrease to the 88,000 GHz at x=0.1.
Structurally, ixiolite can be regarded as a disorder form of columbite, and in the past study, when the ixiolite structure changes to columbite, the peak (040) will appear. At this study, the ordering degree (I040/ I040+ I031) is increase from 9.84 at x=0 to 13.41 x=0.05, so we conjectures the reason of Q×f increase is the ordering degree increase.

1. “Low Loss Dielectric Materials LTCC Applications. A Review,” Int. Mater.,[53] 57-90 (2008).
2. S. Kawashima, M. Nishida, I. Ueda, and H. Ouchi, “Ba(Zn1/3Ta2/3)O3 Ceramics with Low Dielectric Loss atMicrowave-Frequencies,”J. Am. Ceram. Soc.,66 [6] 241 (1983).
3. Matsumoto, T. Hiuga, K. Takada, and H. Ichimura, “Ba(M1/3Ta2/3)O3 Ceramics with Ultra-Low Loss at Microwave-Frequencies,” IEEE Trans. Ultrason., Ferroelectr. Frequency Control, 33 [6] 802 (1986).
4. R. D. Shannon,”Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,” Acta Crystallogr., 32,751 (1976)
5. K. P. Surendran, P. V. Bijumon, P. Mohanan, and M. T. Sebastian,”(1-x)MgAl2O4- xTiO2 system for microwave and millimeter wave applications, ”Phys., 98044101 (2005)
6. C. L. Huang, and J. Y. Chen, “High-Q Microwave Dielectrics in the (Mg1-xCox)2TiO4 Ceramics,” J. Am. Ceram. Soc., 92 [2] 379–383 (2009).
7. S. Astorg, S. Marinel, O. Perez, A. Veres, “Investigation of some niobate-based dielectrics in view of base metal co-sintering,” J. Euro. Ceram. Soc., [27] 4445–4451 (2007).
8. R. C. Pullar “The Synthesis, Properties, and Applications of Columbite Niobates (M+Nb2O6): A Critical Review,” J. Am. Ceram. Soc., 92 [3] 563–577 (2009).
9. H. J. Lee, K. S. Hong and S. J. Kim, “Dielectric Properties of MNb2O6 Compounds
(where M = Ca, Mn, Co, Ni, or Zn),” Mater. Res. Bull., 32 [7] 847-855 (1997).
10. C. L. Huang and J. Y. Chen,” Reduced Dielectric Loss of Modified ZnNb2O6 Ceramics by Substituting Nb5+ with Ta5+,” J. Am. Ceram. Soc., 92 [8] 1845-1848 (2009).
11. T. Hahn, “International Tables for Crystallography Volume A Space-Group Symmetry,” 2nd Rd. (1987)
12. M. T. Sebastian and H. Jantunen. “Low Loss Dielectric Materials LTCC Applications. A Review,” Int. Mater.,[53] 57-90 (2008).
13. H. J. Lee and K. S. Hong, “Crystal structure and microwave dielectric properties of M+(NbxTa1-x)2O6 solid solution (M+ = Mg or Zn),” J. Mater. Res. 12 [6] (1997).

14. Y. C. Zhang, Z. X. Yue, X. Qi, B. Li, Z. L. Gui and L. T. Li,” Microwave dielectric properties of Zn(Nb1-xTax)2O6 ceramics,” Mater. Lett., 58 1392– 1395 (2004).
15. James S. Reed, ”principles of ceramics processing,” second edition.
16. G.. C. Kuczynski, ”Sintering and Related Phenomena,” Gorden and Breach Science Publisher,(1965).
17. W. J. Huppmann and G. Petzow, “The Elementary Mechanisms of Liquid Sintering, Sintering Processes,” Edited by G. C. Kuczynski, New York: Plenum Press, 189-202 (1979).
18. D. K. Cheng, “Field and Wave Electromagnetic,” Addison Wesley, Mass., 407-412 (1989).
19. D. Kajfez, “Computed Modal Field Distribution for Isolated Dielectric Resonators,” IEEE. Trans. MTT, MTT - 32, 1609-1616 (1984).
20. A. C. Larson and R. B. Von Dreele, Los Alamos Laboratory Report LAUR 86-748, Los Alamos National Laboratory, Los Alamos, (1994).
21. H. M. Rietveld, ”Line profiles of neutron powder-diffraction peaks for structure refinement,” Acta. Crystal., [22] 151 (1967).
22. 王俊傑，ZnNb2O6 介電陶瓷材料燒結與微波特性之研究，國立成功大學電機工程研究所碩士論文 (2003)。
23. J. S. Reed, “Principles of Ceramic Processing, Wiley, New York (1988).
24. A. Kan, H. Ogawaa, H. Ohsato,” Influence of microstructure on microwave dielectric properties of ZnTa2O6 ceramics with low dielectric loss,” J. Alloys Compd. 337 303–308 (2002).
25. R. D. Shannon,” Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides,” Acta Crystallogr, A32 751-767 (1976).
26. E. Husson, Y. Repelin, N. Q. Dao, H. Brusset and E. Fardouet,” Etude par spectrophotométries d'absorption infrarouge et de diffusion Raman des niobates de structure columbite,” Spectrochim. Acta, Part A, 33 [11] 995-1001 (1977).
27. C. T. Chia, Y. C. Chen, H. F. Cheng and I N. Lin,”Correlation of microwave dielectric properties and normal vibration modes of xBa (Mg1/3Ta2/3)O3– (1−x)
Ba(Mg1/3Nb2/3)O3 ceramics: I. Raman spectroscopy ” J. Appl. Phys. [94] 3360-3365 (2003).
28. S. M. Ji, S. H. Choi, J. S. Jang, E. S. Kim, and J. S. Lee,” Band Gap Tailored Zn(Nb1-xVx)2O6 Solid Solutions as Visible Light Photocatalysts,” J. Phys. Chem., 113, 17824–17830 (2009).
29. D. W. Kim, D. Y. Kim, and K. S. Hong, ” Phase relations and microwave dielectric properties of ZnNb2O6–TiO2” J. Mater. Res. 15 [6] (2000).
30. S. Butee, A. Kulkarni, O. Prakash, S. George, and M. Sebastian, “High Q Microwave Dielectric Ceramics in (Ni1-x Znx)Nb2O6 System.,” J. Am. Ceram. Soc., 92 [5] 1047–1053 (2009).
31. M. Wenger,T. Armbruster, C. A. Geiger, ” Cation distribution in partially ordered columbite from the Kings Mountain,” Am. Mineral., 76 1897-1904 (1991).
32. A. C. Larson and R. B. Von Dreele, General Structure Analysis System, Los Alamos National Laboratory, Los Alamos (1988).