Microstructure and piezoelectric properties of (Na0.85K0.15)0.5Bi0.5TiO3 lead-free ceramics prepared by tape casting processing

(Na0.85K0.15)(0.5)Bi0.5TiO3 lead-free piezoelectric ceramics were prepared by tape casting process. The effects of heat-treatment on the microstructure and piezoelectric properties of ceramics were investigated. The results show that the ceramics with densified microstructure can be prepared by tape casting process. The microstructure of cross section is not the same dense as that of surface. There are two phases coexist in the ceramics: perovskite phase and K2Ti6O13 phase whose appearance is whisker shape. It is difficult to eliminate K2Ti6O13 by heat-treatment process. But heat-treatment will improve the microstructure of cross section effectively and decrease piezoelectric constant d(33), dielectric constant E and dielectric loss tan delta. (Na0.85K0.15)(0.5)Bi0.5TiO3 lead-free piezoelectric ceramics show obvious characteristic of ferroelectrics with coercive electric field E-c 2680V/mm and remnant polarization P-r 36.6 mu C/cm(2), d33, K-p and Q(m) of ceramics are 113pC/N, 0.27 and 154 respectively.