Enhanced Strain Properties and Temperature Stability in Textured Potassium Niobate Sodium-Based Multilayer Piezoelectric Actuators

In response to the demand for lead-free alternatives for multilayer piezoelectric actuators (MLA), high Curie temperature and environmentally friendly potassium sodium niobate (KNN) based lead-free piezoelectric ceramic systems were selected for the application research of multilayer piezoelectric actuators. In order to enhance the piezoelectric performance of the piezoelectric ceramics, template grain growth (TGG) texturing technology with LTCC multilayer component fabrication techniques was employed to investigate the relevant properties of KNN-based multilayer piezoelectric actuators. Here, a composition system of 0.96(Na0.5K0.5)(Nb0.965Sb0.035)O3-0.01CaZrO3-0.03(K0.5Bi0.5HfO3) (KNNS-KBH-CZ) was chosen, and two types of MLAs, textured and nontextured, were fabricated. Both MLAs consisted of seven dielectric layers with dimensions of approximately 5.2 × 5.2 × 0.81 mm3. The textured KNNS-KBH-CZ exhibited a texturing degree of up to 93%. The textured KNNS-KBH-CZ actuators achieved high displacement performance (unipolar strain of 0.17%, d33* of 563 pm/V) at low field strength (3 kV/mm), showing an improvement of 180% compared to nontextured MLAs (0.094%) and low strain hysteresis (11%), demonstrating the potential application of KNN-based materials in the field of piezoelectric actuators.