On the formation mechanism of BaTiO3–BaZrO3 solid solution through solid-oxide reaction

Abstract

The formation of solid solution composition BaTi 0.6 Zr 0.4 O 3 , from BaCO 3 , TiO 2 and ZrO 2 powders has been studied through solid-oxide reaction using TGA/DSC, XRD. BaCO 3 decomposes at much lower temperature in the mixture due to the presence of TiO 2 . BaTiO 3 and BaZrO 3 start forming from the temperature range 700 o -800 o C without intermediate formation of BaO or other titanate/zirconate phases. Rate of BaTiO 3 formation is higher than BaZrO 3 formation due to the lower activation energy (34.3 kcal/mol) required for titanate formation than zirconate (48.4 kcal/mol). Solid solution then forms by diffusion of BaTiO 3 into BaZrO 3 from 1300 o C onwards. Lattice parameter of initial SS-phase is higher, indicating the phase has a coherent interface with zirconate and higher in Zr-concentration than final product. Activation energy for the SS-formation (133 kcal/mole) indicates that Ba and/or O diffution through SS layer may limit the reaction.

Relaxation and Conduction Mechanisms of High Tc Lead-Free Ba (Zr,Ti)O3 Positive Temperature Coefficient of Resistivity Ceramic Using Impedance Spectroscopy

“…Barium titanate based Ba(Zr,Ti)O 3 (BZT) is one of the most important ceramic having perovskite ABO 3 structure with Zr in the A-site and Ti in the B-site. This material is an excellent candidate for variety of applications such as tunable filters, ring resonators, phase shifter, dynamic random access memories, tunable dielectric devices, multilayer ceramic capacitors, PTCR thermistors, etc [5,6] because it has local polar properties, the phase formation mechanism, dielectric and piezoelectric properties [7][8][9]. Several researchers have reported the PTCT effect in BaTiO 3 -based ferroelectric ceramics.…”

Microstructural and Electrical Study of (BA0.6 SR0.4)(ZR1-X Tix)o3 Ceramics

“…BaZr x Ti 1-x O 3 (BZT) system is one of the most attractive materials due to its phase formation mechanism [9,10] local polar characteristics [11] and dielectric/tunable properties for microwave applications [12,13]. BaTiO 3 (BT) is known to form complete solid state solution with BaZrO 3 (BZ).It has been reported [14] Hrs.…”

Influence of Zr-substitution on phase transitions character in polycrystalline Ba(Ti1−x Zr x )O3

“…During decrease of the temperature in BT sample three phase transitions (PT) take place: first to tetragonal phase, T (*400 K), then to rhombic phase, O (*300 K) and finally to rhombohedral phase, R (*210 K). Synthesis conditions [2,3], piezoelectric [4][5][6] and dielectric investigations [7][8][9][10][11][12] of solid solution BTZx can be found in the literature.…”