Effect of WO3 on the sintering behavior, microstructure, and dielectric loss of Ba(Co1/3Nb2/3)O3 Ceramics

Subject Areas :

Negin Mazrooei ¹ , Ahmad Sayyadi-Shahraki ²

1 - B.Sc. Student, Department of Materials Science and Engineering, Faculty of Engineering, Golpayegan University of Technology, Golpayegan, Iran.
2 - Assistant Professor, Department of Materials Engineering, Islamic Azad University, Karaj, Iran.

Received: 2019-08-18 Accepted : 2019-11-18 Published : 2021-04-21

Keywords: Complex perovskite structures, Microwave dielectric, Dielectric loss, Cation ordering,

Abstract :

In the present work, effect of WO3 dopant on the sintering behavior, microstructure evolution, and microwave dielectric loss of Ba(Co1/3Nb2/3)O3 ceramics were systematically investigated. (1-x) Ba(Co1/3Nb2/3)O3 – (x) WO3 compounds, where x=0, 0.002, 0.004, 0.008, and 0.02, were prepared by the conventional solid state synthesis route followed by sintering at 1300-1450ºC for 10h at air atmosphere. Solid solution limit of WO3 oxide in the Ba(Co1/3Nb2/3)O3 compound and formation of any secondary phase were determined by X-ray diffraction (XRD) technique. In addition, the obtained XRD patterns were simulated by Rietveld refinement and degree of 1:2 cation ordering was calculated based on the refinement results. Scanning electron microscopy (SEM) was employed to study microstructural development of the ceramic samples and to directly identify secondary phase formation and their morphology. XRD results demonstrated that WO3 could solve into Ba(Co1/3Nb2/3)O3 structure for x<0.02, while detailed investigation by SEM directly indicated that even for Ba(Co1/3Nb2/3)O3 – 0.002 WO3 (x=0.002) composition additional phases were precipitated during high-temperature sintering. According to the XRD results, it was found that BaWO4, and Ba9CoNb14O45 compounds were formed as secondary phases. On the other hand, Rietveld refinement simulation showed that addition of WO3 into Ba(Co1/3Nb2/3)O3 results in a significant decline in the 1:2 cation ordering degree, where it was deceased from 95% to 59% when x was increased from x=0 to x=0.02. Quality factor, Q, (inverse of dielectric loss, 1/tanδ) of the prepared ceramics were measured at the microwave frequency range and it was found that incorporation of WO3 noticeably lowered the quality factor of Ba(Co1/3Nb2/3)O3 materials, where Q×f (f denotes resonance frequency) was measured to be 61,000 GHz for x=0 composition, whereas, measurements did not show any resonant peaks for x=0.02 ceramics, which means the ceramics suffer from a huge microwave dielectric loss.

References:

[1] م. کیانی زیتانی و م. رضوانی، "بررسی ویژگی‌های دی‌الکتریک شیشه سرامیک سیستم CaO-SiO₂-MgO در محدوده امواج مایکرویو"، فرآیندهای نوین در مهندسی مواد، سال 4، 1391.

 

[2] ا. پوربافرانی، "ساخت و بررسی خواص ساختاری و جذب امواج الکترومغناطیسی در کامپوزیت‌ها باریوم استرانسیوم تیتانات/فریت کبالت-روی"، فرآیندهای نوین در مهندسی مواد، سال 4، 1396.

 

 [3] S. Penn, N. Alford & H. Nalwa, "Ceramic dielectrics for microwave applications. Handbook of Low and High Dielectric Constant Materials and Their Application", Academic Press, pp. 493-532, 1999.

 

[4] S. Zhang, H. Sahin, E. Torun, F. Peeters, D. Martien, T. DaPron, N. Dilley & N. Newman, "Fundamental mechanisms responsible for the temperature coefficient of resonant frequency in microwave dielectric ceramics", Journal of the American Ceramic Society vol. 100, pp. 1508-1516, 2017.

 

[5] S. Zhang, A. Devonport & N. Newman, "bMain source of microwave loss in transition‐metal‐doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at cryogenic temperatures" Journal of the American Ceramic Society vol. 98, pp. 1188-1194, 2015.

 

[6] S. Ra, "Synthesis, prossesing, and microwave dielectric properties of Barium Zinc Tantalate (Ba(Zn_1/3Ta_2/3)O₃) ceramics for wireless communications", Ph.D. Dissertation, The graduate faculty of the school of engineering, University of Dayton Pittsburgh, 2000. Pittsburgh.

[7] M. T. Sebastian, "Dielectric materials for wireless communication", Elsevier: Amsterdam, pp. 1-49, 2008.

 

[8] I. M. Reaney, Y. Iqbal, H. Zheng, A. Feteira, H. Hughes, D. Iddles, D. Muir & T. Price, "Order–disorder behavior in 0.9Ba ([Zn_0.60Co_0.40]_1/3Nb_2/3) O₃-0.1Ba(Ga_0.5Ta_0.5)O₃ microwave dielectric resonators", Journal of the European Ceramic Society, vol. 25, pp. 1183-1189, 2005.

 

[9] J. Padchasri, R. Yimnirun  & T. Kolodiazhnyi, "Correlation between the 1:2 atomic order and microwave dielectric loss in the off-stoichiometric Ba(Zn_1/3Ta_2/3)O₃", Journal of the European Ceramic Society, vol. 38, pp. 3412-3415, 2018.

 

[10] A. Sayyadi-Shahraki, E. Taheri-Nassaj, J. Gonzales, N. Newman, & T. Kolodiazhnyi. "Effect of non-stoichiometry on the densification, phase purity, microstructure, crystal structure, and dielectric loss of Ba(Co_1/3Nb_2/3)O₃ ceramics", Journal of the European Ceramic Society, vol. 37, pp. 3335-3346, 2017.

 

[11] P. M. Mallinson, J. B. Claridge, M. J. Rosseinsky,  R. M. Ibberson, J. P. Wright, A. N. Fitch, T. Price, & D. M. Iddles. "Cation ordering/disordering kinetics in Ba₃CoNb₂O₉: An in situ study using synchrotron x-ray powder diffraction." Applied Physics Letters, vol. 91, pp. 222901-222901. 2007.

 

[12] C. S. Park, S. Nahm, Y. S. Kim, H. Leey, M. Kimz & J. Byun. "Effect of WO₃ on the Microstructure and Microwave Characteristics of Ba(Zn_1/3Nb_2/3)O₃ Ceramics" Journal of the Korean Physical Society, vol. 32, pp. S340-S342, 1998.

 

[13] M. R. Varma, & M. T. Sebastian. "Effect of dopants on microwave dielectric properties of Ba(Zn_1/3Nb_2/3)O₃ ceramics", Journal of the European Ceramic Society vol. 27, pp. 2827-2833, 2007.

[14] K.P. Surendran, M. T. Sebastian, P. Mohanan, and M. V. Jacob. "The effect of dopants on the microwave dielectric properties of Ba(Mg_{0. 33}Ta_{0. 67})O₃ ceramics", Journal of applied physics, Vol. 98, pp. 094114, 2005.

 

[15] A. G. Belous, O. V. Ovchar, A. V. Kramarenko, B. Jancar, J. Bezjak & D. Suvorov, "Effect of nonstoichiometry on the structure and microwave dielectric properties of Ba(Co_1/3Nb_2/3)O₃", Inorganic Materials, vol. 46, pp. 529-533, 2010.

 

[16] F. Azough, C. Leach & R. Freer, "Effect of nonstoichiometry on the structure and microwave dielectric properties of Ba(Co_1/3Nb_2/3)O₃ ceramics", Journal of the European Ceramic Society vol. 26, pp. 2877-2884, 2006.

 

[17] I. Molodetsky & P. K. Davies, "Effect of Ba(Y_1/2Nb_1/2)O₃ and BaZrO₃ on the cation order and properties of Ba(Co_1/3Nb_2/3)O₃ microwave ceramics", Journal of the European Ceramic Society vol. 21, pp. 2587-2591, 2001.

 

[18] A. Sayyadi‐Shahraki, E. Taheri‐Nassaj, H. Sharifi, J. Gonzales, T. Kolodiazhnyi, & N. Newman, "Origin of dielectric loss in Ba(Co_1/3Nb_2/3)O₃ microwave ceramics", Journal of the American Ceramic Society, vol. 101, pp. 1665-1676, 2018.

 

[19] T. Kolodiazhnyi, G. Annino, & T. Shimada. "Intrinsic limit of dielectric loss in several Ba(B_1/3^′ B_2/3^″)O₃ ceramics revealed by the whispering-gallery mode technique", Applied Physics Letters, vol. 87, pp. 212908-212908, 2005.

 

[20] P. K. Davies, H. Wu, A. Y. Borisevich, I. E. Molodetsky, & L. Farber. "Crystal chemistry of complex perovskites: New cation-ordered dielectric oxides", Annual Review of Materials Research, vol. 38, pp. 369-401, 2008.

 

[21] P. K. Davies, J. Tong, & T. Negas. "Effect of Ordering‐Induced Domain Boundaries on Low‐Loss Ba(Zn_1/3Ta_2/3)O₃‐BaZrO₃ Perovskite Microwave Dielectrics", Journal of the American Ceramic Society, vol. 80, pp. 1727-1740, 1997.

 

[22] D. J. Barber, K. M. Moulding, J. I. Zhou, & M. Li. "Structural order in Ba(Zn_1/3Ta_2/3)O₃, Ba(Zn_1/3Nb_2/3)O₃ and Ba(Mg_1/3Ta_2/3)O₃ microwave dielectric ceramics", Journal of materials science, vol. 32, pp. 1531-1544, 1997.

 

[23] H. Tamura, "Microwave dielectric losses caused by lattice defects", Journal of the European Ceramic Society, vol. 26, pp. 1775-1780, 2006.

 

[24] W. Wersing, "Microwave ceramics for resonators and filters", Solid State and Materials Science, vol. 1, pp. 715-73, 1996.

 

[25] S. J. Penn, N. M. Alford, A. Templeton, X. Wang, M. Xu, M. Reece, & K. Schrapel. "Effect of porosity and grain size on the microwave dielectric properties of sintered alumina", Journal of the American Ceramic Society, vol. 80, pp.1885-1888, 1997.

 

[26] H. Wu, & P. K. Davies. "Influence of Non‐Stoichiometry on the Structure and Properties of Ba(Zn_1/3Nb_2/3)O₃ Microwave Dielectrics: II. Compositional Variations in Pure BZN", Journal of the American Ceramic Society, vol. 89, pp. 2250-2263, 2006.

 

[27] S. H. Yoon, D. W. Kim, S. Y. Cho & K. S. Hong, "Investigation of the relations between structure and microwave dielectric properties of divalent metal tungstate compounds", Journal of the European Ceramic Society, vol. 26, pp. 2051-2054, 2006.

 

[28] H. Zhuang, Z. Yue, F. Zhao, J. Pei & L. Li, "Microstructure and microwave dielectric properties of Ba₅Nb₄O₁₅–BaWO₄ composite ceramics", Journal of Alloys and Compounds, vol. 472, pp. 411-415, 2009.

 

[29] O. Ovchar, D. Durylin, A. Belous & B. Jancar, "A-site deficient perovskites Ba(M²⁺_1/3Nb_2/3)O₃: microstructural attributes for a high quality factor", Materials Science-Poland, vol. 29, pp. 56-62, 2011.

 

[30] T. Kolodiazhnyi, A. Alexei, C. Tadashi & E. Takayama-Muromachi, "Phase equilibria in the BaO–MgO–Ta₂O₅ system", Journal of Materials Chemistry, vol. 19, pp. 8212-8215, 2009.