Domain structure of nonstoichiometric sodium potassium niobate-based ceramics for piezoelectric acoustic actuators

In this work, three piezoelectric acoustic actuators are prepared by using multi-layer technology for lead-free (Na0.48-xK0.48-xLi0.04)Nb0.89-xTa0.05Sb0.06O3-xSrTiO3 (NKLNTS-xST) ceramics, x=0 and 0.007, and commercial lead-based ceramic. The phase and domain structure are also investigated by using the XRD patterns and TEM images of the NKLNTS-xST ceramics. The (Na0.473K0.473Li0.04Sr0.007)Nb0.883Ti0.007Ta0.05Sb0.06O3 piezoelectric acoustic actuator has the best sound pressure level and d33 value of 650 pCN−1. The response mechanisms suggest that the piezoelectric ceramic vibration amplitude was increased and the sound pressure level improved since the orthorhombic and tetragonal phases were found to coexist and the nanoscale domain increased for the (Na0.473K0.473Li0.04Sr0.007)Nb0.883Ti0.007Ta0.05Sb0.06O3 ceramic.