Élaboration et caracterisation de ceramiques ferroelectriques avec et sans plomb.

Abstract

The main objective of this work on the synthesis, the structural and physical characterization of a new lead-free and lead-free ceramic with ABO3 perovskite structure. A substitution was carried out in order to improve its physical property and to determine the densification rate and the grain size of the phase morpho tropic border (FMP) or coexist in two tetragonal and rhombohedral phases of the synthesis (1-x) Pb (1-x) Pb(Zry, Ti1-y)O3-xPb(Fe1/5, Ni1/5, Sb3/5)O3ou x= 20 % et 38≤y≤34 The multiferroic ceramics Bi0.8Ba0.2Fe1-xSbxO3 with x= 0, 0.01, and 0.02 were synthesized using the solid phase reaction technique. The samples were sintered at two different temperatures, 850 and 900 ºC. Scanning electron microscopy revealed the effect of antimony concentration on grain size and formation. The effect of Sb-doping on the crystal structure and ferroelectric properties of these ceramics was investigated using X-ray diffraction, Raman spectroscopy, and dielectric measurements. The dielectric constant was enhanced upon Fe3+ substitution by Sb3+ without affecting the dielectric loss of the ceramics. The tetragonal distortion of the rhombohedral symmetry of BiFeO3 caused by Ba-doping at Bi3+ site was lifted by Sb-doping at Fe3+ site.