Effect of Temperature Path on the Poling of Commercial Hard PZT Ceramics and its Implication for Mass Production

In order to identify process parameters for the efficient poling of hard piezoelectrics in mass production, the effect of temperature modification during poling is investigated for a commercial hard PZT in the temperature range from 25 degrees C to 150 degrees C. While an electric field is applied, the temperature of the specimens was kept constant or the specimens were heated or cooled. The resulting piezoelectric performance was evaluated on the basis of the planar coupling factor at room temperature. An optimal poling temperature associated with maximum piezoelectric performance was found for poling with constant temperature. However, for poling while cooling, even higher performance is attained if the starting temperature is high enough. If poling becomes necessary after fabrication at high temperature, the cooling period could be exploited. The observed correlation between permittivity and the coupling factor could be exploited in quality control.