In the present paper, variation of material properties of piezoelectric ceramics due to impact loading was evaluated, and the mechanisms for the variation were investigated by using X-ray diffraction (XRD). Columnar specimens made of lead zirconate titanate (PZT) ceramics were subjected to compressive impact loading with different impact energies, and variation of material properties and change in spontaneous polarization direction due to the impact loading were investigated. The impact loading was given by a drop-weight impact testing machine. The falling weight was fixed to a constant value, and the falling height was changed systematically. Resonance and anti-resonance frequencies of specimens were measured by an impedance analyzer, and material properties such as an electromechanical coupling coefficient and a piezoelectric constant were evaluated before and after impact loading. Change in crystalline structures was inspected by XRD, and change in spontaneous polarization direction was investigated. Fracture surfaces were observed by SEM, when specimens were fractured. On the basis of experimental results, the relationship between variation of material properties and change in spontaneous polarization direction was discussed, and fracture modes depending on site of fractured specimen were clarified.

piezoelectric ceramics, impact loading, domain switching, XRD, SEM.