The Effect of Nb2O5 Addition on the Structural, Dielectric and Piezoelectric Properties of Pb0,98 Ba0,02 [(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02] Ceramics

Specimens of Pb0,98 Ba0,02[((Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02)] + x wt.% Nb2O5 (x = 0, 0.1, 0.2, 0.3 and 0.4 wt.%) ceramics were prepared by a conventional mixed-oxide route. In the present study, the effect of Nb doping was investigated on the structural, microstructural, dielectric and piezoelectric properties of the ceramics. X-ray diffraction analysis indicated that the phase of the material changed from an rhombohedral structure to a MPB structure and then a tetragonal structure when the Nb2O5 content was increased from 0.00 to 0.40 wt.%. The PBZT–PBCT ceramics doped with 0.20 wt. % of Nb2O5 exhibited denser and finer microstructures, which produced a high relative density of ≥ 97%. Scanning electron microscopy (SEM) observations revealed that Nb2O5 (x) addition enhanced the sintering density through the formation of a liquid phase. The maximum dielectric constant (ɛr = 17100) and the piezoelectric charge coefficient (d31 = 203 pC/N) were observed for 0.20 wt.% of Nb2O5. It has been observed that the dielectric and piezoelectric constants increased gradually with increasing x up to 0.20 and was found optimum, which could be ideal for electromechanical and energy harvesting applications.