An enhanced mechanical quality factor and a low dielectric loss in lithium sodium niobate lead-free ceramics

(Li0.12Na0.88)(Nb0.96−xSb0.04Tax)O3 (LNNST) ceramics were fabricated by the normal sintering. These LNNST ceramics endure a phase transition from an orthorhombic phase, a coexistence of orthorhombic and tetragonal phases, to a tetragonal phase with increasing Ta content. Dense microstructure has been developed for all ceramics. The Tc decreases and the ɛr increases with increasing Ta content, together with a very low dielectric loss of less than 1.3%. A high Qm value of ∼1230 is demonstrated for the ceramic with x = 0.06. Enhanced piezoelectric properties are also demonstrated for the ceramic with x = 0.03 because of a coexistence of two phases. Therefore, this ceramic is a promising candidate for the transducer and transformer applications.