Introduction
Modified K0.5Na0.5NbO3 (KNN)-based lead-free materials were
reported to offer comparable piezoelectric properties to that of PZT
ceramics [1]. Therefore, much effort has been made to improve the
properties of conventional lead-free piezeoelectric ceramics.
Through composition optimization, remarkably strong piezoelectricity
was obtained in KNN-based lead-free ceramics [2–6]. The
tremendous enhancement in the piezoelectricity again attracts
researches’ attention for elaborately designing the composition.
Although the relationship of composition, structure, properties
and processing in material science has been the core of material
research for several decades, most of recent literatures seem to be
focused on the compositions optimization and do not care so much
about the processing parameters. The ceramics with the same
composition prepared via different processes, even if the same
technique but different processing parameters, their macroscopic
performance would make evident difference due to their different
microstructures.