High strain in (K,Na)NbO₃ -based lead-free piezoceramics

A high strain is important for practical applications of piezoelectric actuators. Here we reported a high strain in the (K,Na)NbO₃ -based ceramics by doping alkaline earths or transition metals. The ceramics possess a high strain (∼0.29%) as well as a large converse piezoelectric coefficient (d33∗) up to 688 pm/V, which almost matches that of PZT4 ceramics. The obtained d₃₃∗ is high for nontextured (K,Na)- NbO₃-based ceramics. In addition, a higher d₃₃ value (340-407 pC/N) was also attained in the ceramics. Enhanced d₃₃ and d₃₃∗ values of this work should be attributed to the multiphase coexistence's effect induced by alkaline earths or transition metals. We believe that our research can benefit the developments of (K,Na)NbO₃ ceramics and widen their applications range. (Table Presented).