Formation process of a duplex structure in KSr₂Nb₅O₁₅ ferroelectric ceramics

A unique duplex structure (no grain with an intermediate size) was observed in dense KSr₂Nb₅O₁₅ (KSN) ferroelectric ceramics, which were prepared by the solid-state reaction method using KSN microcrystalline as raw material. A combined experimental and computer simulation study confirmed that the few crystallographic orientations were existent for KSN grains and the adjacent grains were self-assembled by sharing a common orientation. This spontaneous oriented attachment resulted in the direct mergence of KSN grains, which were responsible for accelerating the bigger grains growth to form a duplex structure. This new understanding of the grain growth process could serve as a viable route to controlling density and grains sizes in the design of ferroelectric ceramics, particularly for textured ceramics.