Investigation on the effect of Fe2O3, Nb2O5 and Ta2O5 doping on the electrical properties of BNBT6 lead free piezoelectric ceramics

Keywords: Piezoelectric, BNBT6, Perovskite, Dielectric Lead containing perovskite-based ferroelectric ceramics are widely used as piezoelectric materials. Yet, concerning health problems arising from the use of lead that can damage kidney, brain and nervous system hinder its adoption into these systems. Hence, European Union classified Lead Zirconate Titanate (PZT) as a hazardous material in 2003. Recently, KNN and BNT have been synthesized as alternative systems to replace Lead-PZT materials. In this study, the effect of Fe2O3- Ta2O3 and Fe2O3-Nb2O5 doping on the phase distribution and microstructure of lead- free (BNBT100x- 2F / 2FN / 2FT) x = 0.06 piezoelectric ceramics was evaluated. Stoichiometric amount of powders was thoroughly mixed and subjected to calcination heat treatment process. Mixed powders were again milled and sieved. Subsequently the granulated powders were cold pressed at 100 MPa. The pellets were sintered under ambient atmosphere at 1150 C. Phase analysis and grain morphology of the samples were carried out by XRD and SEM analyses respectively. FTIR analysis was performed to analyze the bond structure of the samples. Lastly, evaluation on the practical application of the study was discussed. Our study reveals that Fe2O3 - Ta2O5 and Fe2O3 - Nb2O5 doping further increases the dielectric constant compared to bare Fe2O3 doping. In all compositions, density above %93 were obtained after sintering.