Synthesis And Electrical Characterisation of Lanthanum Doped Barium Titanate Zirconate

BaTi0.6Zr0.4O3 powder was prepared from powders containing barium oxalate hydrate, zirconium oxy-hydroxide and titanium dioxide. Barium oxalate hydrate and zirconium oxy-hydroxide were precipitated from nitrate solution onto the surface of suspended TiO2. Phase formation behaviour of the materials was extensively studied using XRD. BaTiO3 (BT) and BaZrO3 (BZ) start forming separately in the system upon calcinations in the temperature range 600–700oC. BT-BZ solid solution then forms by diffusion of BT into BZ from 1050oC onwards. The precursor completely transforms into BaTi0.6Zr0.4O3 (BTZ) at 1200oC for 2 hours calcinations. The activation energy of BT (134 kJ mol-1) formation was found to be less than that of BZ (167.5 kJ mol-1) formation. BTZ formation requires 503.6 kJ mol-1 of energy. The sintering kinetics of the powder was studied using thermal analyzer. The mean activation energy for sintering was found to be 550 kJ mol-1