Structures and piezoelectric properties of (Bi_0.5Na _0.5)TiO₃-(Na_0.5K_0.5)NbO₃ based lead-free ceramics

Lead-free (1-x)(Bi_0.5Na_0.5)TiO₃-xNa _0.5K_0.5NbO₃, (x = 0-8 mol%) (abbr., BNT-xNKN) solid solutions were fabricated by mechanical alloying technique. XRD and SEM showed the crystal structure of the samples become more tetragonal and their grain size become small with the increase of substitution. Dielectric studies revealed that the phase transition temperatures shift to low temperature with the increase of NKN. The piezoelectric properties of BNT-xNKN can not be enhanced with the increase of NKN, but their dielectric properties have been improved. The results show that the BNT-xNKN ceramics are one of the promising lead-free materials for capacitor applications.