Effect of magnetic CoFe2O4 component on sintering densification process of Bi3.15Nd0.85Ti3O12 ceramics

Sintering densification processes of the composite ceramics (Bi3.15Nd0.85Ti3O12 (BNdT)/CoFe2O4 (CFO)) have been investigated using dilatometric experiments combining with the TG-DTA, density measurements and microstructure studies. Microstructures analyses and quantitative calculations show that the composite ceramics achieve densification at low temperatures (<1150 °C). The formation of coherent-lattice interfaces between (200)/(020)BNdT and (310)CFO are considered to play an important role on such densification. The intrinsic preferred orientation of BNdT grains is suppressed by CFO phase because of this coherent relationship. Although the sintering activation energies of 0.8BNdT-0.2CFO are about 2.7 times larger than those of pure BNdT due to the pinning effect, the composite ceramic could still be densified, indicating the formation energy of coherent-lattices provided the extra sintering force. The even coercive electric fields of the resulting pure BNdT and 0.8BNdT-0.2CFO ceramic are approximately 89 and 97 kV/cm, respectively, at 250 kV/cm. The polarization of 0.8BNdT-0.2CFO reaches saturation around 430 kV/cm.