Piezoelectric and ferroelectric properties of Bi-compensated (Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3 lead-free piezoelectric ceramics

Abstract

Multiferroic response of nanocrystalline lithium niobate J. Appl. Phys. 111, 07D907 (2012) Non-radiative complete surface acoustic wave bandgap for finite-depth holey phononic crystal in lithium niobate ͑Bi 1/2 Na 1/2 ͒TiO 3 -͑Bi 1/2 K 1/2 ͒TiO 3 ͑BNT-BKT͒ ceramics as a promising candidate for lead-free piezoelectric ceramics were studied with a special emphasis on the compositional dependence of piezoelectric and ferroelectric properties. One mole percent excess Bi was added to compensate for the volatilization of Bi 3+ ions during sintering, which was found to be effective in improving the piezoelectric properties of the resultant BNT-BKT ceramics. The piezoelectric, ferroelectric, and dielectric properties of the Bi-compensated BNT-BKT ceramics were investigated and discussed in relation to the morphotropic phase boundary that is close to the composition range of 20-24 mol % BKT. The maximum piezoelectric constant d 33 ͑207 pC/N͒ and electromechanical coupling factor k p ͑35%͒ were obtained at the compositions of 23% and 20%, respectively.

Sintering and dielectric properties of perovskite SrTaO2N ceramics

“…The tan δ values are all approximately 0.04 at 1 MHz, which is still higher than that required for practical applications. The number of grain boundaries was increased in the SrTaO 2 N-Sr/La bulks due to the smaller grain size, leading to an accumulation of the space charge [33]. This may be one reason for the high dissipation factor.…”

Enhanced temperature stability and quality factor with Hf substitution for Sn and MnO2 doping of (Ba0.97Ca0.03)(Ti0.96Sn0.04)O3 lead-free piezoelectric ceramics with high Curie temperature

“…3 Proposed alternatives to lead-based piezoelectric ceramics include BaTiO 3 (BT), (K,Na)NbO 3 (KNN), (Bi,Na)TiO 3 (BNT), (Ba,Ca)(Ti,Zr)O 3 (BCTZ), (Ba,Ca)(Ti,Sn)O 3 (BCTS), and (Ba,Ca) (Ti,Hf)O 3 (BCTH). [4][5][6][7] Some researchers have reported that BCTZ and BCTS ceramics can potentially replace lead-based piezoelectric ceramics because of their high piezoelectric properties. The morphotropic phase boundary (MPB) in PZT ceramics has extremely high dielectric, ferroelectric, and piezoelectric properties, which are caused by enhanced polarizability due to coupling between equivalent energy states of ferroelectric tetragonal (T) and ferroelectric rhombohedral (R) phases, making domain switching easy.…”

Pyroelectric, dielectric, and piezoelectric properties of MnO2-doped (Na0.82 K0.18)0.5Bi0.5TiO3 lead-free ceramics

“…For its relatively large remanent polarization (P r 038 μC/cm 2 ) at room temperature and high Curie temperature (T c 0320°C), BNT has been considered to be a good candidate for lead-free piezoelectric ceramics. However, for pure BNT, it is difficult to pole due to high coercive field (E c 073 kV/cm) and high conductivity, which will make its piezoelectric and pyroelectric properties much lower than PZT ceramics [3]. To improve the piezoelectric and pyroelectric properties of the material, a number of BNT-base solid solutions, such as BNT-BaTiO 3 , BNT-Bi 0.5 K 0.5 TiO 3 , BNT-NaNbO 3 , BNT-KNbO 3 , BNT-Bi 0.5 K 0.5 TiO 3 -Bi 0.5 Li 0.5 TiO 3 and BNT-Bi 0.5 K 0.5 TiO 3 -BaTiO 3 have been studied extensively [4][5][6][7][8][9].…”