Abstract
Powders of the solid lead-free piezoelectric ceramic solution [Na0.5K0.5NbO3]1−x–[LiTaO3]x, x = 0.06, were produced using a mixed-oxide process. Phase analysis indicated the formation of an orthorhombic solid solution at 800 °C, which coexisted with intermediate binary niobate and tantalate phases. A tetragonal main-phase solid solution was formed at ⩾950 °C, along with minor quantities of a tungsten bronze phase. Addition of 3 wt% excess alkali carbonates to the starting powders allowed the orthorhombic solid solution to be retained to 1100 °C and prevented formation of the secondary tungsten bronze phase. Elemental chemical analysis confirmed changes in alkali oxide composition, consistent with volatilization losses, particularly of potassium and lithium oxides. Phase stability near the reported morphotropic phase boundary is shown to be sensitive to alkali oxide content.
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European Council Directive 2002/95/EC of the European Parliament and Council of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment. Off. J. Eur. Union L37, 19 2003
IEEE IEEE Standard on Piezoelectricity, ANSI/IEEE Standard No. 176 IEEE New York 1987
T. Takenaka H. Nagata: Current status and prospects of lead-free piezoelectric ceramics. J. Eur. Ceram. Soc. 25, 2693 2005
H. Yilmaz, S. Trolier-McKinstry G.L. Messing: (Reactive) Templated grain growth of textured sodium bismuth titanate (Na1/2Bi1/2TiO3–BaTiO3) ceramics—I. Processing. J. Electroceram. 11, 207 2003
H. Yilmaz, S. Trolier-McKinstry G.L. Messing: (Reactive) Templated grain growth of textured sodium bismuth titanate (Na1/2Bi1/2TiO3–BaTiO3) ceramics—II. Dielectric and piezoelectric properties. J. Electroceram. 11, 217 2003
L. Egerton D.M. Dillon: Piezoelectric and dielectric properties of ceramics in the system potassium–sodium niobate. J. Am. Ceram. Soc. 42(9), 438 1959
L. Egerton R.E. Jaeger: Hot pressing of potassium–sodium niobates. J. Am. Ceram. Soc. 45(5), 209 1962
G.H. Haertling: Properties of hot-pressed ferroelectric alkali niobate ceramics. J. Am. Ceram. Soc. 50(6), 329 1967
B. Jaffe, W.R. Cook H. Jaffe: (eds.) Piezoelectric ceramics in Non-metallic Solids Academic Press London 1971 Vol. 3
Y. Guo, K. Kakimoto H. Ohsato: (Na0.5K0.5)NbO3–LiTaO3 lead-free piezoelectric ceramics. Mater. Lett. 59(2-3), 241 2005
Y. Guo, K. Kakimoto H. Ohsato: Phase transitional behaviour and piezoelectric properties of (Na0.5K0.5)NbO3–LiNbO3 ceramics. Appl. Phys. Lett. 85, 4121 2004
Y. Saito, H. Takao, I. Tani, T. Nonoyama, K. Takatori, T. Homma, T. Nagaya M. Nakamura: Lead-free piezoceramics. Nature 432, 84 2004
Y. Saito H. Takao: High performance lead-free piezoelectric ceramics in the (K,Na)NbO3–LiTaO3 solid solution system. Ferroelectrics 338, 17 2006
R. Zuo, J. Rödel, R. Chen L. Li: Sintering and electrical properties of lead-free Na0.5K0.5NbO3 piezoelectric ceramics. J. Am. Ceram. Soc. 89(6), 2010 2006
E. Hollenstein, M. Davis, D. Damjanovic N. Setter: Piezoelectric properties of Li- and Ta-modified (Na0.5K0.5)NbO3 ceramics. Appl. Phys. Lett. 87(182905), 1 2005
J-F. Li, K. Wang, B-P. Zhang L-M. Zhang: Ferroelectric and piezoelectric properties of fine-grained Na0.5K0.5NbO3 lead-free piezoelectric ceramics prepared by spark plasma sintering. J. Am. Ceram. Soc. 89(2), 706 2006
R. Wang, R-J. Xie, K. Hanada, K. Matsusaki, H. Bando M. Itoh: Phase diagram and enhanced piezoelectricity in the strontium titanate doped potassium–sodium niobate solid solution. Phys. Status Solidi 202(6), R57 2005
B-P. Zhang, J-F. Li, K. Wang H. Zhang: Compositional dependence of piezoelectric properties in NaxK1−xNbO3 lead-free ceramics prepared by spark plasma sintering. J. Am. Ceram. Soc. 89(5), 1605 2006
G-Z. Zang, J-F. Wang, H-C. Chen, W-B. Su, C-M. Wang, P. Qi, B-Q. Ming, J. Du, L-M. Zheng, S. Zhang T.R. Shrout: Perovskite (Na0.5K0.5)1−x(LiSb)xNb1−xO3 lead-free piezoceramics. Appl. Phys. Lett. 88, 212908 2006
JCPDS No. 00-033-1270. International Center for Diffraction Data Newton Square PA 1980
JCPDS No. 00-032-0822. International Center for Diffraction Data Newton Square PA 1981
JCPDS No. 00-020-0631. International Center for Diffraction Data Newton Square PA 1968
JCPDS No. 00-029-0836. International Center for Diffraction Data Newton Square PA 1977
M. Ahtee A.M. Glazer: Lattice parameters and tilted octahedra in sodium–potassium niobate solid solutions. Acta Crystallogr. A32, 434 1976
JCPDS No. 00-034-0122. International Center for Diffraction Data Newton Square PA 1982
JCPDS No. 00-052-0157. International Center for Diffraction Data Newton Square PA 1977
P. Bomlai, W. Wichianrat, S. Muensit S.J. Milne: Effect of calcination conditions and excess alkali carbonate on the phase formation and particle morphology of Na0.5K0.5NbO3 powders. J. Am. Ceram. Soc. 90(5), 1650 2007
JCPDS No. 01-071-0945. International Center for Diffraction Data Newton Square PA 1997
JCPDS No. 00-016-0459. International Center for Diffraction Data Newton Square PA 1963
A.D. Pelton, C.W. Bale P.L. Lin: Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH. Can. J. Chem. 62, 457 1984
L.F. Volkova: Figure 1015 in Phase Diagrams for Ceramists edited by E.M. Levin, C.R. Robbins, and H.F. McMurdie The American Ceramic Society Westerville, OH 1964
A.I. Kingon J.B. Clark: Sintering of PZT ceramics: I—Atmosphere control. J. Am. Ceram. Soc. 66(4), 253 1983
A.I. Kingon J.B. Clark: Sintering of PZT ceramics: II—Effect of PbO content on densification kinetics. J. Am. Ceram. Soc. 66(4), 256 1983
ACKNOWLEDGMENTS
The authors thank the Engineering and Physical Sciences Research Council (EPSRC) for a studentship award. Appreciation is expressed to P. Bomlai, Prince Songkla University, Thailand, and to colleagues at the University of Leeds.
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Skidmore, T., Milne, S. Phase development during mixed-oxide processing of a [Na0.5K0.5NbO3]1−x–[LiTaO3]x powder. Journal of Materials Research 22, 2265–2272 (2007). https://doi.org/10.1557/jmr.2007.0281
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DOI: https://doi.org/10.1557/jmr.2007.0281