Modification of barium titanate sintering via rare earth oxides addition: Dilatometric and microstructural study

Abstract

In this paper, the effect of rare-earth dopants (RE: Ce, Eu, Tb, Dy, and Er) in barium titanate (BT) on the shaping, sintering and microstructure was studied aimed mainly at selecting appropriate dopant for densification delaying while preserving optimal BT characteristics. The addition of dopant oxides into suspension resulted in the reduction of the deposition kinetics. The relative density of doped green bodies was lower than pure BT and decreased with dopant concentration. Only Ce enhanced green density up to 2%. The sintering process was studied using high-temperature dilatometry. The hindering densification caused by dopants was observed, but only 5 wt % of Tb and Er in BT shifted the onset of sintering to higher temperatures that has the potential applicability of these materials in layered ceramic harvesters. The significant positive impact of doping on the microstructure was attained almost in all cases manifesting themselves in higher sintered densities and markedly lower mean grain size compared to pure BT. The XRD and Raman spectroscopy analyses confirmed incorporation of the dopants into the perovskite structure and no significant existence of RE-enriched secondary phases in the microstructure.