(1-phi) (0.93 Na0.5Bi0.5TiO3-0.07 BaTiO3)-phi Sr0.8Bi2.15Ta2O9/(1-phi) (NBT-BT)-phi SBexT (phi = 0, 2, 4, 8, 12, 16 wt %) ferroelectric ceramic samples were synthesized by solid state reaction technique. 1150 degrees C for 4hr was optimized as the sintering temperature for all the ceramic samples. XRD, SEM, dielectric, leakage current, ferroelectric and piezoelectric properties along with the ferroelectric fatigue behaviour under bipolar electrical loading of all the (1-phi) (NBT-BT)-phi SBexT ceramic samples were studied in detail. Incorporation of SBexT phase into the MPB composition of the NBT-BT system significantly affected the various studied properties. Improvement in leakage current density and better fatigue behaviour were observed in SBexT incorporated NBT-BT ceramic systems. (C) 2016 Elsevier B.V. All rights reserved.