Textured Potassium Sodium Niobate Lead-Free Ceramics with High d₃₃ and Q_m for Meeting High-Power Applications

Abstract

Potassium sodium niobate (KNN) lead-free piezoceramics have garnered significant attention for their environmentally friendly attributes, desired piezoelectric activity (d 33 ), and high Curie temperature (T c ). However, the limited applicability of most KNN systems in high-power apparatus, including ultrasonic motors, transformers, and resonators, persists due to the inherent low mechanical quality factor (Q m ). Herein, we proposed an innovative strategy for achieving high Q m accompanied by desirable d 33 via synergistic chemical doping and texturing in KNN piezoceramics. Comprehensive electrical measurements along with quantitative structural characterization at multilength scales reveal that the excellent electromechanical properties (k p = 0.58, d 33 ∼ 134 pC•N -1 , Q m = 582, and T c ∼ 415 °C) originate from the high <001> texturing degree, nanodomain, as well as acceptor hardening. Our findings provide an insight and guidance for achieving high-power performance in lead-free KNN-based piezoceramics, which were expected to be used in advanced transducer technology.