The Influence of the Firing Temperatures on the Phase Evolution, Microstructure, Dielectric and Strain Responses of BCTS Ceramics Prepared by the Solid State Combustion Technique

Abstract

In this report, the influence of the firing temperatures on the phase evolution, microstructure, dielectric and strain responses of (Ba0.945Ca0.055)(Ti0.91Sn0.09)O3 (BCTS) lead‐free piezoelectric ceramics is investigated. BCTS ceramics are prepared with the solid state combustion technique with glycine as the fuel. Pure BCTS powders, with a perovskite structure, are obtained by calcining at 1150 °C for 2 h. The particle morphology of the BCTS powders exhibits a rounded shape and large agglomerated forms in all samples. The average particle size increases from 158 to 223 nm when the calcination temperature is increased from 1050 to 1250 °C. The XRD results of the sintered samples show they all have a single perovskite structure. The Rietveld refinement analysis indicates that the BCTS ceramics sintered at 1400 °C have the orthorhombic (O), tetragonal (T), and rhombohedral (R) phases coexisting while the O + T phases coexist in the other samples. The average grain size, density, dielectric constant (at Tc), %strain, and d33* increase when the sintering temperature is increased up to 1400 °C and then, reduced in values. At the optimum sintering temperature (1400 °C), BCTS ceramic show multi phases (O + T + R), good crystalline morphology, the highest density (98%), an excellent dielectric constant (ϵc ≅ 16 252), and a good d33* value (866 pm/V).