Effect of Silver Electrode Annealing Temperature on Electrical Properties of Sodium Potassium Niobate Based Ceramics

Annealing of the electrodes before poling is an inevitable step in the processing of piezoceramics and, hence, the optimization of annealing temperature is necessary to obtain higher properties. However, for sodium potassium niobate based lead free piezoceramics, the data available is very puzzling, and the annealing temperature has not been standardized. In this study, the optimum ceramic - electrode interface has been designed by modulating the electrode annealing temperature to attain the best possible properties. The annealing temperature, ranging from 150°C to 750°C, has been investigated using piezoelectric properties, resistivity, dielectric properties, adhesion strength and interface of electrode-ceramic boundaries as parameters. The measured properties demonstrated significant dependence on the characteristics of the ceramic-electrode interface. For lead free piezoceramic, optimum properties are achieved at the annealing temperature of 450°C which has been attributed to the well- bonded homogeneous ceramic-electrode interface.