Abstract: BaTiO3-doped Bi0.5(Na0.82 K 0.18)0.5TiO3 lead-free thick films were prepared on Pt-electroded alumina substrates using screen printing , their phase structure , microstructure , dielectric , piezoelectric and ferroelectric properties were investigated .The results show that the morphotropic phase boundary (MPB) of (1-x)BNKT-xBaTiO3 thick films was in the x range of 3mol;-7mol;.5mol; BT-doped BNKT (95BNKT-5BT) thick films exhibited preferable relative dielectric constant of 793, piezoelectric coefficient of 72 pC/N, remnant polarization of 4.35 μC/cm2 , unipolar strain value of 0.817;. However, the addition of 5mol; BT increases the dielectric loss from 1.1; to 6.2;, and also increases the coercive field from 35.77 kV/cm to 53.72 kV/cm.In the end, the prepared 95BNKT-5BT thick films were used to make the soud film , with the help of the driver circuit , the lead-free piezoelectric speaker for protable electronic device was developed .

Key words: BaTiO3-doped Bi0.5(Na0.82 K 0.18)0.5TiO3 lead-free thick films were prepared on Pt-electroded alumina substrates using screen printing , their phase structure , microstructure , dielectric , piezoelectric and ferroelectric properties were investigated .The results show that the morphotropic phase boundary (MPB) of (1-x)BNKT-xBaTiO3 thick films was in the x range of 3mol;-7mol;.5mol; BT-doped BNKT (95BNKT-5BT) thick films exhibited preferable relative dielectric constant of 793, piezoelectric coefficient of 72 pC/N, remnant polarization of 4.35 μC/cm2 , unipolar strain value of 0.817;. However, the addition of 5mol; BT increases the dielectric loss from 1.1; to 6.2;, and also increases the coercive field from 35.77 kV/cm to 53.72 kV/cm.In the end, the prepared 95BNKT-5BT thick films were used to make the soud film , with the help of the driver circuit , the lead-free piezoelectric speaker for protable electronic device was developed .