Influences of temperature and electric field on the bending strength of lead zirconate titanate ceramics Original Research Article

The present work studies the effects of temperature and a d.c. electric field on the bending strength of PZT-841 ceramics using three-point bending measurement. In the temperature range from 30°C to the Curie point Tc (≈272°C), the bending strength as a function of temperature exhibits a valley shape and the valley floors at a temperature around 225°C, revealing a 25% reduction in comparison with the bending strength at room temperature. Meanwhile, elastic compliance and damping factor exhibit peaks, respectively, at 225°C and 220°C, implying a strong correlation between bending strength and compliance. A positive or negative electric field larger than 3 kV/cm reduces the bending strength of PZT-841 ceramics significantly. For example, the bending strength under a positive field of 20 kV/cm is only one half of that without application of any electric field. The electric field is able to fracture mechanically sustained samples. Under a constant load of 70 MPa, the mean value of the critical electric field at fracture is 11.0 kV/cm. A 90°-domain wall kinetic model is herein proposed to understand the observed phenomena.