Dielectric and Piezoelectric Properties of Lead Free
(1-x)[(Na0.5Bi0.5)TiO3]- x[Ba(Zr0.2Ti0.8)O3(Ba0.7Ca0.3)TiO3] Ceramics
Ganesh K. Sahoo and Ranabrata Mazumder*
Department of Ceramic Engineering,
National Institute of Technology,
Rourkela-769008, Odisha, India.
Piezoelectric materials used today are mostly based on lead-containing compounds, which can
have a negative effect on human health and the environment. However, the recent concern about
environmental pollution from lead based materials has generated renewed interest in developing
lead free piezoelectrics. (Na0.5Bi0.5)TiO3 (NBT) is one of the important leadfree piezoelectric
materials with high Curie temperature Tc (320℃) and high remnant polarization ( Pr=38
μC/cm2). The major drawback of this material is its high conductivity which restricts proper
poling. Recently, Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 (BZT-BCT) ceramics have attracted great
attention due to excellent piezoelectric properties (d33~300-600pC/N). It has low Curie
temperature (93°C), which limit their application. In this report lead-free (1-x) NBT- x(BZTBCT) (where x=0, 0.03,0.05,0.07) has been prepared by planetary milling. The effect of BZTBCT on the phase formation, microstructure, electrical properties of NBT have systematically
been studied. It has been found that single phase perovskite structure can be obtained at a
temperature as low as 700°C. It is found that these powders can be sintered at 1100°C upto a
density of more than 97% of the theoretical density. It is observed that the relative permittivity of
NBT ceramic increases with increase in BZT-BCT concentration, simultaneously Curie
temperature shifts to 250oC. Interestingly, the dielectric and piezoelectric properties of such lowtemperature sintered samples are at par with and in some cases better than those of the NBT and
NBT-BT composition sintered at high temperature. To the best of our knowledge, we first time
present such a low-temperature synthesis (700°C) and sintering of NBT- (BZT-BCT) ceramics
without hampering its dielectric and piezoelectric properties of NBT. The composition is
expected to be a new and promising candidate as lead free piezoelectric ceramics.
* Presenting author’s e-mail: rana_brata@hotmail.com