Increasing demand for environmentally friendly materials in both electronic and automotive industries promotes extensive studies on lead-free piezoelectrci materials in order to replace Pb-based ones that contain over 60 wt% Pb. In this work, we studied the dielectric, ferroelectric, field-induced strain properties of Bi-based lead-free perovskite ceramics with A- or B-site dopants or other ABO3 compounds. Many Bi-based ceramics were found to show large normalized strains in the range of Smax/Emax = 500 � 700 pm/V at RT near ferroelectric-relaxor phase transition region. However, there still remain several challenges to be overcome for field applications; large strain-field hysteresis, high electric-field to trigger large strain, and strain stability in a limited temperature range. In order to overcome such barriers, we attempted to prepare ceramic-ceramic composites by embedding ferroelectric particles in a relaxor matrix, resulting in lowering the triggering field even though the maximum strain was almost unchanged. The ceramic-ceramic composites are believed to enlighten a new road to large strain lead-free alternatives of Pb-based actuator materials.

Large strain lead-free piezoelectric ceramics with ceramic-ceramic composite structures

248th National Meeting (2014)

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