Enhancing Electrical Properties in NBT-KBT Lead-Free Piezoelectric Ceramics by Optimizing Sintering Temperature

Conventional sintering of (Na1−xKx)0.5Bi0.5TiO3 (abbreviated as NKBTx, x=18–22 mol%) lead-free piezoelectric ceramics was investigated to clarify the optimal sintering temperature for densification and electrical properties. Both sintered density and electrical properties were sensitive to sintering temperature; particularly, the piezoelectric properties deteriorated when the ceramics were sintered above the optimum temperature. The NKBT20 and NKBT22 ceramics synthesized at 1110°–1170°C showed a phase transition from tetragonal to rhombohedral symmetry, which was similar to the morphotropic phase boundary (MPB). Because of such MPB-like behavior, the highest piezoelectric constant (d33) of about 192 pC/N with a high electromechanical coupling factor (kp) of about 32% were obtained in the NKBT22 ceramics sintered at 1150°C.

[1]  Qing Xu,et al.  Piezoelectric and ferroelectric properties of Na0.5Bi0.5TiO3–K0.5Bi0.5TiO3–BaTiO3 piezoelectric ceramics , 2005 .

[2]  H. Nagata,et al.  Lead-Free Piezoelectric Ceramics of (Bi1/2Na1/2)TiO3–KNbO3–1/2(Bi2O3·Sc2O3) System , 1997 .

[3]  H. Nagata,et al.  Morphotropic Phase Boundary and Electrical Properties of Bisumuth Sodium Titanate–Potassium Niobate Solid-Solution Ceramics , 2001 .

[4]  T. Tunkasiri,et al.  Sintering of Fe-doped Bi0.5Na0.5TiO3 at < 1000 °C , 2007 .

[5]  Tadashi Takenaka,et al.  (Bi1/2Na1/2)TiO3-BaTiO3 System for Lead-Free Piezoelectric Ceramics , 1991 .

[6]  Pilar Ochoa,et al.  Sintering and properties of lead-free (K,Na,Li)(Nb,Ta,Sb)O3 ceramics , 2007 .

[7]  Jingfeng Li,et al.  Preparation and properties of (Bi1/2Na1/2)TiO3-Ba(Ti,Zr)O3 lead-free piezoelectric ceramics , 2005 .

[8]  X. X. Wang,et al.  Effect of excess Bi2O3 on the electrical properties and microstructure of (Bi1/2Na1/2)TiO3 ceramics , 2005 .

[9]  X. X. Wang,et al.  Electromechanical and ferroelectric properties of (Bi1∕2Na1∕2)TiO3–(Bi1∕2K1∕2)TiO3–BaTiO3 lead-free piezoelectric ceramics , 2004 .

[10]  H. Fan,et al.  Effect of sintering temperature on the structure and properties of cerium-doped 0.94(Bi0.5Na0.5)TiO3–0.06BaTiO3 piezoelectric ceramics , 2008 .

[11]  J. Kreisel,et al.  An x-ray diffraction and Raman spectroscopy investigation of A-site substituted perovskite compounds: the (Na1-xKx)0.5Bi0.5TiO3 (0 x1) solid solution , 2000 .

[12]  J. Kreisel,et al.  A structural study of the (Na1−xKx)0.5Bi0.5TiO3 perovskite series as a function of substitution (x) and temperature , 2002, Powder Diffraction.

[13]  Q. Yin,et al.  Electrical properties of Na1/2Bi1/2TiO3–BaTiO3 ceramics , 2002 .

[14]  A. Ding,et al.  Ferroelectric and piezoelectric properties of (Na, K)0.5Bi0.5TiO3 lead free ceramics , 2006 .

[15]  D. Lin,et al.  Investigation on the design and synthesis of new systems of BNT-based lead-free piezoelectric ceramics , 2006 .

[16]  Jingfeng Li,et al.  High piezoelectric d33 coefficient in Li-modified lead-free (Na,K)NbO3 ceramics sintered at optimal temperature , 2007 .

[17]  P. Bhattacharya,et al.  Local structure of the lead-free relaxor ferroelectric (KxNa1-x)0.5Bi0.5TiO3 , 2005 .

[18]  Jingfeng Li,et al.  Piezoelectric and ferroelectric properties of Bi-compensated (Bi1/2Na1/2 )TiO3-(Bi1/2K1/2)TiO3 lead-free piezoelectric ceramics , 2008 .

[19]  G. Smolensky,et al.  New ferroelectrics of complex composition. IV , 1961 .

[20]  Jingfeng Li,et al.  Normal Sintering of (K,Na)NbO3‐Based Ceramics: Influence of Sintering Temperature on Densification, Microstructure, and Electrical Properties , 2006 .

[21]  Etsuo Otsuki,et al.  Dielectric and Piezoelectric Properties of (Bi0.5Na0.5)TiO3–(Bi0.5K0.5)TiO3 Systems , 1999 .

[22]  Hajime Nagata,et al.  Large Piezoelectric Constant and High Curie Temperature of Lead-Free Piezoelectric Ceramic Ternary System Based on Bismuth Sodium Titanate-Bismuth Potassium Titanate-Barium Titanate near the Morphotropic Phase Boundary , 2003 .