Chemical Composition-Microstructure-Dielectric Constant Relations of Mg-Doped Calcium Titanate Synthesized by Solid State Reaction Technique

Abstract:

It has been generally accepted that doping of dielectric materials could significantly contribute to compositional and microstructural evolution, which consequently lead to alteration in dielectric properties. In this study, the effects of adding magnesium (Mg) at 5,10 and 20at% on the chemical composition, microstructure and dielectric constant of calcium titanate (CaTiO₃) synthesized by solid state reaction was assessed. Chemical composition analysis using an X-ray diffraction technique CaTiO₃ doped with 5 at% Mg has been found to contain a single phase whereas samples doped with 10 and 20 at% Mg both exhibited apparent secondary phase (MgO). Microstructural examination however, revealed that no significant variation in particle size, grain size and density were evident among the samples of different Mg contents. Average dielectric constants obtained from the entire samples ranged from 245.9 to 387.6 (at 1 MHz) and the sample with the highest dielectric constant was that doped with 5 at% Mg. Enhancement of dielectric constant in the samples with the lowest level of Mg doping has been attributed largely to the homogeneity of its chemical composition.

• Periodical: Key Engineering Materials (Volume 751)
• Pages: 390-396
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.751.390
• Online since: August 2017
• Authors: Oratai Jongprateep*, Nicha Sato, Jednupong Palomas, Pongsakorn Jantaratana
• Keywords: Calcium Titanate, Dielectric Constant, Doping, Solid State Reaction

References

[1] S. Sahoo, U. Dash, S.K.S. Parashar and S.M. Ali, Frequency and temperature dependent electrical characteristics of CaTiO3 nano-ceramic prepare by high-energy ball milling, Journal of Advanced Ceramics (2013), 2(3), 291-300.

DOI: 10.1007/s40145-013-0075-8

[2] C.L. Huang and M.H. Weng, Improved high Q value of MgTiO3-CaTiO3 microwave dielectric ceramics at low sintering temperature. Materials Research Bulletin 36 (2001), 2741-2750.

DOI: 10.1016/s0025-5408(01)00752-8

[3] H. Su and S. Wu, Studies on the (Mg, Zn)TiO3-CaTiO3 microwave dielectric ceramics. Materials Letters 59 (2005), 2337-2341.

DOI: 10.1016/j.matlet.2005.01.087

[4] O. Mondal, M. Pal, R. Singh, D. Sen, D. Mazumder and M. Pal, Influence of doping on crystal growth, structure and optical properties of nanocrystalline CaTiO3: a case study using small-angle neutron scattering, Journal of Applied Crystallography. (2015).

DOI: 10.1107/s1600576715006664

[5] Y.L. Chai, Y.S. Chang, K.T. Liu and L.G. Teoh, The structure and PTCR effects of Mg-doped ZnTiO3 ceramics. Ceramics International 38. (2012), 3613-3618.

DOI: 10.1016/j.ceramint.2011.12.078

[6] W. Luan, L. Gao and J. Guo, Size effect on dielectric properties of fine-grained BaTiO3 ceramics, Ceramics International 25. (1999) 727-729.

DOI: 10.1016/s0272-8842(99)00009-7

[7] P. Zheng, J.L. Zhang, Y.Q. Tan and C.L. Wang, Grain-size effects on dielectric and piezoelectric properties of poled BaTiO3 ceramics, Acta Materialia 60(13–14), (2012), 5022-5030.

DOI: 10.1016/j.actamat.2012.06.015

[8] Y. Sakabe, N. Wada and Y. Hamaji, Grain size effects on dielectric properties and Crystal structure of fine-grained BaTiO3 ceramics. Journal of the Korean Physical Society, Vol. 32, pp. S260-S264, Feb (1998).

[9] B.W. Lee and K.H. Auh, Effect of grain size and mechanical processing on the dielectric properties of BaTiO3. J. Mater. Res., Vol. 10, No. 6, Jun (1995).

[10] Y.S. Chang, Y.H. Chang, I.G. Chen and G.J. Chen, Synthesis and characterization of zinc titanate doped with magnesium. Solid State Communications 128. (2003), 203-208.

DOI: 10.1016/s0038-1098(03)00527-1

[11] 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 83.

DOI: 10.1111/j.1151-2916.2000.tb01156.x

[1] (2006), 107-112.

[12] Y. Li, X.P. Gao, G.R. Li, G.L. Pan, T.Y. Yan and H.Y. Zhu, Titanate nanofiber reactivity: fabrication of MTiO3 (M = Ca, Sr and Ba) perovskite oxides. J. Phys. Chem. (2009), C113: 4386-4394.

DOI: 10.1021/jp810805f

[13] S. Manafi and M. Jafarian, Synthesis of perovskite CaTiO3 nanopowders with different morphologies by mechanical alloying without heat treatment. International Journal of Physical Sciences. Vol. 8(23), (2013), pp.1277-1283.

[14] O. Jongprateep, A. Chansuriya and S. Rugthaichareoncheep, Composition and particle size of REBa2Cu3O7-x superconductor powders synthesized by solid state reactions. Suranaree. J. Sci. Technol. 19(3), (2013), 155-160.

[15] O. Jongprateep and J. Palomas, Effects of Mg addition and sintering temperatures on chemical composition, microstructures, densities and dielectric properties of strontium titanate. Ceramics International 41, (2015), 563-568.

DOI: 10.1016/j.ceramint.2015.03.192

[16] J.S. Park and Y.H. Han., Effects of MgO coating on microstructure and dielectric properties of BaTiO3. Journal of the European Ceramic Society 27. (2007), 1077-1082.

DOI: 10.1016/j.jeurceramsoc.2006.05.073

[17] S.H. Yoon, C.A. Randall and K.H. Hur, Influence of grain size on impedance spectra and resistance degradation behavior in acceptor (Mg)-doped BaTiO3 ceramics. Journal of the American Ceramic Society 92.

DOI: 10.1111/j.1551-2916.2009.03305.x

[12] (2009), 2944-2952.

[18] C.L. Huang, C.L. Pan and S.J. Shium, 2002 Liquid phase of MgTiO3 – CaTiO3 microwave dielectric ceramics. Materials Chemistry and Physics 78 (2002), 111-115.

DOI: 10.1016/s0254-0584(02)00311-5

[19] S. Penn, N. Alford, A. Templeton, X. Wang, M. Reece and K. Schrapel, Effect of porosity and grain size on the microwave dielectric properties of sintered alumina. J. Am. Ceram. Soc., 80(7), (1996), 1885-88.

DOI: 10.1111/j.1151-2916.1997.tb03066.x

[20] K. Wakino, A new proposal on mixing rule of the dielectric constant of mixture. IEEE (1995).