Study on the Structure, Morphology, Dielectric, and Piezoelectric Properties of Large-Grain (Ba<sub>0.85</sub>Sr<sub>0.15</sub>)<sub>1–<i>x</i></sub>Pb<sub><i>x</i></sub>TiO<sub>3</sub> Ceramic System for 0.02 ≤ <i>x</i> ≤ 0.08
M. Mesrar, Laila Mesrar, Abdelhalim Elbasset, Nor-Said Echatoui, Farid Abdi, T. Lamcharfi
Abstract
High Resolution Image Download MS PowerPoint Slide Barium strontium lead titanate ((Ba 0.85 Sr 0.15 ) 1– x Pb x TiO 3 ), along with various compositions ( x (mol %) = 0, 2, 4, and 8), was synthesized through the conventional sol–gel reaction method. Following this, the resultant powders underwent a carefully controlled calcination process at 1000 °C for a period of 4 h. The examination of the crystalline phase of the calcined ceramics was conducted at room temperature using X-ray diffraction. Rietveld refinement of the XRD data, performed using FullProf, revealed that the samples exhibited a tetragonal structure within the space group P4mm. The impact of Pb doping on the lattice structure of BaSr 1– x TiO 3 was explored by analyzing the charge density distribution. The FTIR analysis unveiled a distinct absorptive band within the 450–600 cm –1 range, indicative of the stretching and bending vibrations associated with TiO 6 octahedra. Notably, sintering the material at 1150 °C for 4 h resulted in improved densification, as observed in scanning electron microscopy images showcasing a nearly uniform distribution of densely packed grains. Through the utilization of Williamson–Hall plots derived from XRD data, the average particle diameter was estimated to fall within the range of 131.87–141 nm, with an associated uncertainty ranging from 5 to 10%. Additionally, the dielectric characteristics unveiled the presence of a negative dielectric constant (ε r ) spanning the frequency range from 1 kHz to 2 MHz. The (Ba 0.85 Sr 0.15 ) 1– x Pb x TiO 3 ceramic displayed a widespread occurrence of negative permittivity, emphasizing the influence of dielectric resonance. The investigation revealed that the sintered ceramic with the formula (Ba 0.85 Sr 0.15 ) 1– x Pb x TiO 3 exhibited exceptional piezoelectric properties, achieving the highest piezoelectric constant (d 33 = 137 pC/N) and electromechanical coupling factor ( k p = 0.49).