Repetitive grain growth behavior in nano-sized $BaTiO_3$ system and its applications

Abstract

Grain growth inhibition, densification and unimodal size distribution of MLCC dielectric layer is important in order to achieve high capacity at the same time as thinning. Therefore, it is a need for experiments to understand and control the densification and grain growth of nano-sized $BaTiO_3$ dielectrics for MLCC. Repetitive abnormal grain growth was observed during the sintering of nano-sized $BaTiO_3$. The primary abnormal grain growth occurred, and the abnormal grains impinged upon each other at the beginning. During extended sintering for 24h, however, some of the impinged abnormal grains grew, showing secondary abnormal grain growth behavior. These observed repetitive abnormal grain growth is well explained with the coupling effect of the maximum driving force for grain growth in the sample and the critical driving force for the appreciable migration of faceted boundaries. Additionally, the combining of the 2-step and hetero-atmosphere sintering processes can suppress the abnormal grain growth of nano-sized $BaTiO_3$ and effectively promote densification even at low temperatures.