Control of the structure, morphology and dielectric properties of bismuth titanate ceramics by praseodymium substitution using an intermediate fuel agent-assisted self-combustion synthesis

Abstract

The volatilization of bismuth (Bi) species and bismuth oxide (Bi2O3) leads to the presence of the oxygen vacancies (VO00) and consequently restrains the properties of bismuth titanate (BIT; Bi4Ti3O12). This report presents the incorporation of different atomic ratios of praseodymium ion (Pr3+: x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) into the BIT (Bi4−xPrxTi3O12) ceramics through an intermediate fuel agent-assisted self-combustion synthesis (IFSC). X-ray diffraction and Raman spectroscopy results revealed that some of bismuth ion (Bi3+) in the pseudo-perovskite layer containing Ti–O octahedra was substituted by Pr3+ ion. The substitution by ion with a smaller ionic radius caused the structure distortion and consequently resulted in the phase transformation from an orthorhombic symmetry to a tetragonal symmetry. Besides, it suppressed the volatilization of Bi and Bi2O3 and increased the stability of metal–oxygen octahedra in the BIT. These play a crucial role to control the crystal growth, as well as limit the VO00. Dense ceramic with a relative density up to 96.2% was obtained by incorporating Pr3+ with atomic ratio of 1.0. It exhibited high dielectric constant as 908.19 and low dissipation factor as 0.0011. The results address the possibility to control the structure, morphology and dielectric properties of BIT ceramic by incorporating Pr3+ ion through IFSC.